                                      TO VIEW PROPERLY YOU MAY NEED TO SET YOUR 
                                      BROWSER'S CHARACTER ENCODING TO UNICODE 8 
                                      or 16 AND USE YOUR BACK BUTTON TO RE-LOAD.




CRUISE REPORT: P10_2005
(Updated MAY 2009)


A.  HIGHLIGHTS


                           CRUISE SUMMARY INFORMATION

                 Section Designation  P10_2005
              Expedition Designation  49NZ20050525
                     Chief Scientist  TAKESHI KAWANO/IORGC/JAMSTEC
                        Cruise Dates  25 MAY 2005 - 2 JUL 2005
                                Ship  R/V Marai
                       Ports of Call  Sekinehama, Japan to Hachinohe, Japan  
                                      Hachinohe, Japan to Guam, U.S.A.

                                                  42°15.20'N
               Geographic Boundaries  143°44.01'E            149°23.31'E
                                                   4°00.90'S
                            Stations  124
        Floats and Drifters Deployed  2 Argo Floats
      Moorings Deployed or Recovered  0

                       Chief Scientist Contact Information:

                                 Takeshi Kawano
          Institute of Observational Research for Global Change (IORGC)
          Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
                    2-15, Natsushima, Yokosuka, 237-0061, Japan
    Tel: +81-46-867-9471 • Fax: +81-46-867-9455 • E-mail: kawanot@jamstec.go.jp







                        WHP P10 REVISIT DATA BOOK

                                              Edited by Takeshi Kawano (JAMSTEC)
                                                        Hiroshi Uchida (JAMSTEC)


Published by (c) JAMSTEC, Yokosuka, Kanagawa, 2007
    Japan Agency for Marine-Earth Science and Technology
    2-15 Natsushima, Yokosuka, Kanagawa. 237-0061, Japan
    Phone +81-46-867-9471, Fax +81-46-867-9455
Printed by Ryoin Co., Ltd.
    3-3-1, Minatomirai, Nishi-ward, Yokohama, 220-8401, Japan


CONTENTS

PREFACE 
      M. Fukasawa (JAMSTEC) 

DOCUMENTS AND .SUM FILES 
  Cruise Narrative 
      T. Kawano (JAMSTEC) 
  Underway Measurements  
    Navigation and Bathymetry 
      T. Matsumoto, (Univ. Ryukyus), Y. Imai, S. Okumura, R. Ohyama 
         (GODI)
    Surface Meteorological Observation 
      K. Yoneyama (JAMSTEC), Y. Imai, S. Okumura, and R. Ohyama (GODI) 
    Thermosalinograph and related measurements 
      T. Kawano (JAMSTEC) and T. Seike (MWJ) 
    Underway pCO2 
      A. Murata (JAMSTEC), 
      F. Shibata, M. Kitada, T. Ohama and Y. Ishikawa (MWJ) 
    Acoustic Doppler Current Profiler 
      Y. Yoshikawa, S. Kouketsu (JAMSTEC), 
      Y. Imai, S. Okumura and R. Ohyama (GODI) 

  HYDROGRAPHIC MEASUREMENT TECHNIQUES AND CALIBRATIONS 
    CTD/O2 Measurements 
      H. Uchida, M. Fukasawa (JAMSTEC), 
      S. Ozawa, N. Takahashi, K. Oyama and T. Noguchi (MWJ)
    Salinity 
      T. Kawano (JAMSTEC), 
      F. Kobayashi, K. Katayama and T. Tanaka (MWJ) 
    Oxygen 
      I. Kaneko, Y. Kumamoto (JAMSTEC), 
      T. Seike, A. Yasuda and K. Nishijima (MWJ) 
    Nutrients 
      M. Aoyama (MRI/JMA), J. Hamanaka, A. Kubo, A. Takeuchi (MWJ) 
    Dissolved Inorganic Carbon (CT) 
      A. Murata (JAMSTEC), 
      F. Shibata, M. Kitada, T. Ohama and Y. Ishikawa (MWJ) 
    Total Alkalinity (AT) 
      A. Murata (JAMSTEC), 
      F. Shibata, M. Kitada, T. Ohama and Y. Ishikawa (MWJ) 
    pH 
      A. Murata (JAMSTEC), 
      F. Shibata, M. Kitada, T. Ohama and Y. Ishikawa (MWJ) 
    Chlorofluorocarbons (CFCs)
      K. Sasaki, M. Wakita (JAMSTEC), K. Sagishima and H. Yamamoto 
         (MWJ)
    Lowered Acoustic Doppler Current Profiler 
      S. Kouketsu and Y. Yoshikawa (JAMSTEC)

  STATION SUMMARY
    49MR0502_1 .sum file

FIGURES
  Figure captions
  Station locations
  Bathymetry 
  Surface wind
  Sea surface temperature and salinity
  ∆pCO2
  Surface current
  Cross-sections
  Potential temperature
      Salinity 
      Salinity (with SSW correction)
      Density (σ0)
      Density (σ4)
      Neutral density (yn)
      Oxygen 
      Silicate 
      Nitrate 
      Nitrite 
      Phosphate 
      Dissolved inorganic carbon 
      Total alkalinity 
      pH 
      CFC-11 
      CFC-12 
      CFC-113 
      Velocity 

  Difference between WOCE and the revisit 
      Potential temperature 
      Salinity (with SSW correction) 
      Oxygen 

  .sum, .sea, .wct and other data files CD-ROM on the back cover 


PREFACE 

The observation line that we occupied during the period from 25th May to 2nd 
July, 2005 was mostly along the meridian of 149°20'E and was overlaid on WOCE 
Hydrographic Program: WHP P10 line with the northern extension to the coast of 
the Hokkaido, Japan. As the result, 30 new stations were added to the former 
P10 stations and the total number of WHP stations has increased to 124. 

P10 is the third WHP line that IORGC/JAMSTEC occupied by following the 
CLIVAR/Carbon Repeat Hydrography Program (currently renamed as International 
Repeat Hydrography and Carbon Program: IRHC), which was advocated at 
OceanObs99. 

The objectives of the program were defined as follows: 
Comprehensive objectives of repeat hydrography were proposed/defined 


1) to investigate inter annual and longer-term variations in the ocean 
   circulation and associated net property transports and their divergences, 
2) to quantify net changes in water mass inventories and renewal rates on 
   seasonal to decadal time series, and to explore their relationships to 
   estimated ocean transport divergences and air-sea exchanges. 

After OceanObs99, the Argo project has started and is getting the right track 
now. Argo has much more frequency of observation than any other hydrographic 
observation under IRHC. However, hydrographic observation still remains and 
will remain to be the only mean to directly measure the full suite of water 
characteristics with vertical high resolution and with high accuracy of 
measurements. Therefore, the IRHC and Argo Project are complementary to each 
other toward understanding of phenomena at shallower and intermediate depths. 
On the other hand, the unique long-term objectives of IRHC could be sharpened 
as "To investigate inter-annual and long-term variations in the ocean 
circulation and associated net property transports and their divergence, and to 
explore their relationships to air-sea exchange". These unique objectives can 
be supported only through a global network of the core ship-based hydrography, 
which follows the traditional WOCE manner with full suite of its measurements. 

The Ocean General Circulation Observational Research Program of 
IORGC*/JAMSTEC** has a plan to carry out seven core ship-based hydrography 
along WHP P6, A10, I4+I3, P10, P3, P1 and P14 until 2007. Of these lines, re-
visits of P6, A10, I4+I3, P10 and P3 were completed and quite a few excellent 
scientific results have already published by numerous number of scientists, not 
only of IORGC but also of other institutions throughout the world. Anyone can 
refer and use data from these re-visits without any restriction through data 
books we already published and through web sites of IORGC ***, CCHDO****, and 
CDIAC*****. 

Lastly, we would heartily ask favors of all scientists to refer these data 
books as often as possible. Such references are the only proof that this repeat 
hydrography activity is closely connected to the science and makes all of us 
brave enough to continue to maintain the IRHC net work. 


On Christmas Day of 2006, at Yokosuka. 


Masao Fukasawa 
Deputy Director-General IORGC/JAMSTEC, 
Program Director Ocean General Circulation Observational Research Program 
IORGC/JAMSTEC 
*Institute of Observational Research for Global Change 
**Japan Agency for Marine-Earth Science and Technology 
*** http://www.jamstec.go.jp/iorgc/ocorp/data/post-woce.html 
****CLIVAR and Carbon Hydrographic Data Office (http://whpo.ucsd.edu/) 
*****Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov/) 



1 CRUISE NARRATIVE 

1.1 HIGHLIGHT 

WOCE Line Designation:   P10 (Extended to northern end of Japanese 
                              mainland up to Hokkaido) 
Expedition Designation:  MR05-02 
Chief Scientist:         Takeshi Kawano 
                         Institute of Observational Research for Global 
                           Change (IORGC) 
                         Japan Agency for Marine-Earth Science and 
                           Technology (JAMSTEC) 
                         2-15, Natsushima, Yokosuka, 237-0061, Japan        
                         Tel: +81-46-867-9471, Fax: +81-46-867-9455 
                         E-mail: kawanot@jamstec.go.jp 

Ship:                    R/V MIRAI 
Ports of Call:           Sekinehama, Japan - Hachinohe, Japan - Guam, U.S.A. 

Cruise Dates:            May 25, 2005 -July 2, 2005 
Number of Stations:      124 stations for CTD/Carousel Water Sampler 
Geographic boundaries:   143°44.01'E - 149°23.31'E 
                           4°00.90'S -  42°15.20'N 

Floats and drifters deployed:  2 Argo Floats 
Mooring deployed or recovered: NONE 


1.2 CRUISE SUMMARY 

(1) GEOGRAPHIC BOUNDARIES 

MR05-02 occupied stations along about 149°20'E, from 42°15'N to 4°00'S. 


(2) STATION OCCUPIED 

A total of 124 stations were occupied using a Sea-Bird Electronics 36 bottle 
carousel equipped with 12 liter Niskin X water sample bottles, a SBE911plus 
equipped with SBE35 deep ocean standards thermometer, SBE43 oxygen sensor, 
Seapoint sensors Inc. Chlorophyll Fluorometer and Benthos Inc. Altimeter and 
RDI Monitor ADCP. Cruise track and station location are shown in Fig. 1.2.1. 
The stations south of 28°N were revist of the previous P10 cruise conducted in 
1994. The stations north of 34°N were designed to trace the track of Jason-1 
altimeter. 


(3) SAMPLING AND MEASUREMENTS 

Water samples were analyzed for salinity, oxygen, nutrients, CFC11, CFC12, 
CFC113, total alkalinity, DIC and pH. The sampling layers in dbar were 10, 50, 
100, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 
1800, 2000, 2200, 2400, 2600, 2800, 3000, 3250, 3500, 3750, 4000, 4250, 4500, 
4750, 5000, 5250, 5500, 5750 and bottom (minus 10 m). Samples for PON, 14C, 
13C, 15N, Pu and 137Cs were also collected. The bottle depth diagram is shown 
in Fig. 1.2.2. Underway measurements of pCO2, temperature, salinity, oxygen, 
surface current, bathymetry and meteorological parameters were made along the 
cruise track. Biological parameters such as chlorophyll a and nitrogen fixation 
rate were measured at the selected stations. 


(4) FLOATS AND DRIFTERS DEPLOYED 

Two ARGO floats were launched along the cruise track. The launched positions of 
the ARGO floats are listed in 


Table.1.2.1. Table 1.2.1. Launched positions of the ARGO floats. 
________________________________________________________________________________

 Float  ARGOS   Date and Time   Date and Time                             CTD 
 S/N    PTT ID  of Reset (UTC)  of Launch (UTC)   Location of Launch     St. No. 
 -----  ------  --------------  --------------  -----------------------  ------
 1575   23732   15:03, Jun. 13  17:09, Jun. 13  19-50.14 N, 149-19.62 E  P10-60 
  223    6497   19:37, Jun. 15  23:44, Jun. 15  15-15.25 N, 149-20.00 E  P10-53 
________________________________________________________________________________



(5) MOORINGS DEPLOYED OR RECOVERED 
    No mooring was deployed nor recovered during the cruise. 


1.3 LIST OF PRINCIPAL INVESTIGATOR AND PERSON IN CHARGE ON THE SHIP 

The principal investigator (PI) and the person in charge responsible for the 
major parameters measured on the cruise are listed in Table 1.3.1. 


Table 1.3.1. List of Principal Investigator and Person in Charge on the ship. 
________________________________________________________________________________

 Item            Principal Investigator            Person in Charge on the Ship
 --------------  --------------------------------  ---------------------------- 
 UNDERWAY                   
   ADCP          Yasushi Yoshikawa (JAMSTEC)       Yasutaka Imai (GODI) 
                   yoshikaway@jamstec.go.jp          
   Bathymetry    Takeshi Matsumoto (U. Ryukyus)    Yasutaka Imai (GODI) 
                   tak@sci.u-ryukyu.ac.jp          
   Meteorology   Kunio Yoneyama (JAMSTEC)          Yasutaka Imai (GODI) 
                   yoneyamak@jamstec.go.jp          
   T-S           Takeshi Kawano (JAMSTEC)          Takayoshi Seike (MWJ) 
                   kawanot@jamstec.go.jp           
   pCO2          Akihiko Murata (JAMSTEC)          Mikio Kitada (MWJ) 
                  akihiko.murata@jamstec.go.jp          

 HYDROGRAPHY                   
   CTD/O2        Hiroshi Uchida (JAMSTEC)          Satoshi Ozawa (MWJ) 
                   huchida@jamstec.go.jp           
   Salinity      Takeshi Kawano (JAMSTEC)          Fujio Kobayashi (MWJ) 
                   kawanot@jamstec.go.jp           
   Oxygen        Ikuo Kaneko (JAMSTEC)             Takayoshi Seike (MWJ) 
                   Ikuo-kaneko@jamstec.go.jp          
   Nutrients     Michio Aoyama (MRI)               Junko Hamanaka (MWJ) 
                   maoyama@mri-jma.go.jp           
   DIC           Akihiko Murata (JAMSTEC)          Mikio Kitada (MWJ) 
                   akihiko.murata@jamstec.go.jp          
   Alkalinity    Akihiko Murata (JAMSTEC)          Fuyuki Shibata (MWJ) 
                   akihiko.murata@jamstec.go.jp          
   pH            Akihiko Murata (JAMSTEC)          Taeko Ohama (MWJ) 
                   akihiko.murata@jamstec.go.jp          
   CFCs          Kenichi Sasaki (JAMSTEC)          Katsunori Sagishima (MWJ) 
                   ksasaki@jamstec.go.jp           
   LADCP         Shinya Kouketsu (JAMSTEC)         Shinya Kouketsu (JAMSTEC) 
                   skouketsu@jamstec.go.jp          
   ∆14C & δ13C   Yuichiro Kumamoto(JAMSTEC)        Akihiko Murata (JAMSTEC) 
                   kumamoto@jamstec.go.jp          
   137Cs & Pu    Michio Aoyama (MRI)               Akihiko Murata (JAMSTEC) 
                   maoyama@mri-jma.go.jp           
   15N           Hisayuki Yoshikawa (Hokkaido U.)  Tomomi Takamura (Hokkaido U.) 
                   hyoshika@ees.hokudai.ac.jp          
   Biology       Ken Furuya (U. Tokyo)             Satoshi Kitajima (U. Tokyo) 
                   furuya@fs.a.u-tokyo.ac.jp          

 FLOATS, DRIFTERS                   
   Argo float    Nobuyuki Shikama (JAMSTEC)        Naoko Takahashi (MWJ) 
                   nshikama@jamstec.go.jp          
________________________________________________________________________________
  GODI: Global Ocean Development Inc.
  JAMSTEC: Japan Agency for Marine-Earth Science and Technology
  MRI: Meteorological Research Institute, Japan Meteorological Agency
  MWJ: Marine Works Japan, Ltd. 
  Univ. Ryukyus: University of the Ryukyus 
  


1.4 SCIENTIFIC PROGRAM AND METHODS 


(1) Objectives of MR05-02 cruise project 

It is well known that the oceans play a central role in determining global 
climate. However, heat and material transports in the ocean and their temporal 
changes have not yet been sufficiently quantified. Therefore, the global 
climate change is not understood satisfactorily. The purposes of this research 
are to evaluate heat and material transports including carbon, nutrients, etc., 
in the North Pacific and to detect its long term changes and basin-scale 
biogeochemical changes since the 1990s. 

P10 is the hydrographic section nominally along 149°E from Hokkaido, Japan, to 
the coast of Papua New Guinea. The P10 cruise was the first in two WHP re-visit 
cruise aboard R/V MIRAI in 2005 followed by P3. The other objectives of this 
cruise are as follows; 1) to observe surface meteorological and hydrogical 
parameters as a basic data of the meteorology and the oceangraphy, 2) to 
observe sea bottom topography, gravity and magnetic fields along the cruise 
track to understand the dynamics of ocean plate and the accompanying 
geophysical activities, 3) to contribute to establishment of data base for 
model validation, 4) ARGO sensor calibration and its deployment in the western 
Pacific. 


(2) CRUISE OVERVIEW 

MR05-02 cruise was carried out during the period from May 25, 2005 to July 2, 
2005. The cruise started from the coast of Hokkaido and sailed towards 
southeast along the track of Jason-1 (TOPEX/POSEIDON). This line was observed 
several times during the period from 1997-2000 as a part of the SAGE (Sub-
Arctic Gyre Experiment) and called OICE (Oyashio Intensive observation line off 
Cape Eriomo). The cruise course was changed southward at Station 105 (33°45'N, 
149°20'E) and the stations from Station 73 (28°30'N, 149°20'E) were revisit 
of WOCE Hydrographic Program section P10. A total of 124 stations were 
observed. At each station, full-depth CTD profile and up to 36 water samples 
were taken and analyzed. Water samples were obtained from fixed layers with 12-
liter Niskin bottles attached to 36-position SBE carousel water sampler. The 
sampling layers were 10, 50, 100, 150, 200, 150, 200, 250, 300, 400, 500, 600, 
700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 2600, 2800, 
3000, 3250, 3500, 3750, 4000, 4250, 4500, 4750, 5000, 5250, 5500, 5750 dbar and 
about 10 dbar above the bottom. Scientists of JAMSTEC and Meteorological 
Research Institute and technicians of Marine Works Japan Ltd. (MWJ) were 
responsible for analyzing water sample for salinity, dissolved oxygen, 
nutrients, CFCs, total carbon contents, alkalinity and pH. They also 
contributed to sampling for total organic carbon, radiocarbon and so on. 
Students of University of Tokyo and Hokkaido University joined the cruise for 
their research on chemical and biological oceanography. A scientist from 
University of the Ryukyus was a principal investigator for geological 
parameters (topography, geo-magnetic field and gravity). Technicians from 
Global Ocean Development Inc. (GODI) had responsibility on a part of underway 
measurements such as current velocity by Acoustic Doppler Current Profiler 
(ADCP) geological parameters (topography, geo-magnetic field and gravity), and 
meteorological parameters. Two ARGO floats prepared by JAMSTEC were launched by 
MWJ technicians and ship crew. 


(3) CRUISE NARRATIVE 

R/V Mirai departed Sekinehama (Japan) on May 25, 2005. She called on the port 
of Hachinohe (Japan) on May 26, 2005 for bunkering. She arrived at the first 
station on May 27 and made a cast for 445m. Before the first station, all 
watchstanders were drilled in the method of sample drawing. We made a cast at 
Station P10-1 on June 28, 2005 and then went to Guam, U.S.A. We observed 124 
stations along approximately 149°20'E, which is, namely WHP P10. She arrived 
at Guam on July 2, 2005. 


1.5 MAJOR PROBLEMS AND GOALS NOT ACHIEVED 

Water sampler miss-fired 15 times, and consequently, samples were not obtained 
at 13 layers. 


1.6 LIST OF PARTICIPANTS 
  
The members of the scientific party are listed in Table 1.6.1 along with their 
main tasks undertaken on the cruise.   


Table 1.6.1. List of cruise participants.   
_____________________________________________________________________________

 Name                 Main tasks                         Affiliation 
 -------------------  ---------------------------------  -------------------
 Hideyuki FUTAMURA    Water Sampling                     MWJ   
 Junko HAMANAKA       Nutrients                          MWJ            
 Miyo IKEDA           Water Sampling                     MWJ           
 Yasutaka IMAI        Meteorology                        GODI          
 Tetsuya INABA        Water Sampling                     MWJ        
 Yoshiko ISHIKAWA     Carbon                             MWJ             
 Kenichi KATAYAMA     Salinity                           MWJ           
 Takeshi KAWAO        Chief Scientist/Salinity           IORGC/JAMSTEC  
 Mikio KITADA         Carbon                             MWJ                 
 Satoshi KITAJIMA     Biology                            University of Tokyo 
 Fujio KOBAYASHI      Salinity                           MWJ                 
 Shinya KOUKETSU      LADCP/ADCP                         IORGC/JAMSTEC  
 Asako KUBO           Nutrients                          MWJ                 
 Kazuma KUDO          Water Sampling                     MWJ         
 Akihiko MURATA       Carbon                             IORGC/JAMSTEC    
 Kimiko NISHIJIMA     Dissolved Oxygen                   MWJ  
 Tomohide NOGUCHI     CTD                                MWJ   
 Taeko OHAMA          Carbon                             MWJ   
 Shinya OKUMURA       Meteorology                        GODI     
 Kentaro OYAMA        CTD                                MWJ     
 Ryo OYAMA            Meteorology                        GODI     
 Satoshi OZAWA        CTD                                MWJ 
 Katsunori SAGISHIMA  CFCs                               MWJ
 Kenichi SASAKI       CFCs                               MIO/JAMSTEC
 Kenichiro SATO       Chief Technologist/Water Sampling  MWJ 
 Takayoshi SEIKE      Dissolved Oxygen                   MWJ
 Fuyuki SHIBATA       Carbon                             MWJ 
 Naoko TAKAHASHI      CTD                                MWJ 
 Tomomi TAKAMURA      C-13                               Hokkaido University 
 Ayumi TAKEUCHI       Nutrients                          MWJ 
 Tatsuya TANAKA       Salinity                           MWJ 
 Tomokazu TANIGUCHI   Water Sampling                     MWJ 
 Hiroshi UCHIDA       LADCP/CTD                          IORGC/JAMSTEC 
 Satoshi UDA          Water Sampling                     MWJ 
 Masahide WAKITA      CFCs                               MIO/JAMSTEC 
 Hideki YAMAMOTO      CFCs                               MWJ 
 Ai YASUDA            Dissolved Oxygen                   MWJ 
 Masashi YASUNAGA     Water Sampling                     MWJ 
 Atsushi YOSHIMURA    Water Sampling                     MWJ 
 ---------------------------------------------------------------------------
 GODI:    Global Ocean Development Inc. 
 MWJ:     Marine Works Japan Ltd. 
 JAMSTEC: Japan Agency for Marine-Earth Science and Technology 
 IORGC:   Institute of Observational Research for Global Change 
 MIO:     Mutsu Institute for Oceanography 
_____________________________________________________________________________



2 UNDERWAY MEASUREMENTS 


2.1 NAVIGATION AND BATHYMETRY 
    (2 August 2005)
 

(1) PERSONNEL 
    Takeshi Matsumoto (University of the Ryukyus), PI for bathymetry
    Yasutaka Imai (GODI)
    Shinya Okumura (GODI)
    Ryo Ohyama (GODI)


(2) NAVIGATION 


(2.1) OVERVIEW OF THE EQUIPMENT 

The ship's position was measured by navigation system, made by Sena Co. Ltd, 
Japan. The system has two 12-channel GPS receivers (Leica MX9400N). GPS 
antennas were located at Navigation deck, offset to starboard and portside, 
respectively. We switched them to choose better receiving state when the number 
of GPS satellites decreased or HDOP increased. But the system sometimes lost 
the position while the receiving status became worse. The system also 
integrates gyro heading (Tokimec TG-6000), log speed (Furuno DS-30) and other 
navigation devices data on HP workstation. The workstation keeps accurate time 
using GPS Time server (Datum Tymserv2100) via NTP (Network Time Protocol). 
Navigation data was recorded as "SOJ" data every 60 seconds. 


(2.2) DATA PERIOD 
      07:00, 25 May 2005 to 00:00, 2 July 2005 (UTC) 


(3) BATHYMETRY 


(3.1) OVERVIEW OF THE EQUIPMENT 

R/V MIRAI equipped a Multi Narrow Beam Echo Sounding system (MNBES), SEABEAM 
2112.004 (SeaBeam Instruments Inc.). The main objective of MNBES survey is 
collecting continuous bathymetry data along ship's track to make a contribution 
to geological and geophysical investigations and global datasets. Data interval 
along ship's track was max 17 seconds at 6,000 m. To get accurate sound 
velocity of water column for ray-path correction of acoustic multibeam, we used 
Surface Sound Velocimeter (SSV) data at the surface (6.2 m), and sound velocity 
profiles calculated from temperature and salinity data obtained from the 
nearest CTD cast by using the equation of Mackenzie (1981). 


(3.2) SYSTEM CONFIGURATION AND PERFORMANCE 

System:                 SEABEAM 2112.004 
Frequency:              12 kHz 
Transmit beam width:    2 degree 
Transmit power:         20 kW 
Transmit pulse length:  3 to 20 msec. 
Depth range:            100 to 11,000 m 
Beam spacing:           1 degree athwart ship 
Swath width:            150 degree (max) 
                        120 degree to 4,500 m 
                        100 degree to 6,000 m 
                        90 degree to 11,000 m 
Depth accuracy          Within < 0.5% of depth or ±1m, whichever is greater, 
                          over the entire swath. 
                        (Nadir beam has greater accuracy; typically within <0.2% 
                          of depth or ±1m, whichever is greater) 


(3.3) DATA PERIOD

Bathymetric survey was carried out on the CTD observation line during the 
cruise. 

26 May 2005 (P10N_143) to 28 June 2005 (P10_1)


(3.4) DATA PROCESSING 

(3.4.1) EDITING FOR THE NAVIGATION DATA 

Erroneous data in the navigation data are manually removed (by using "mbedit" 
module of the mbsystem) and linearly interpolated. 


(3.4.2) SOUND VELOCITY CORRECTION 

The continuous bathymetry data are split into small areas around each CTD 
station. For each small area, the bathymetry data are corrected using a sound 
velocity profile calculated from the CTD data in the area. The equation of 
Mackenzie (1981) is used for calculating sound velocity. The data processing is 
carried out using "mbbath" module of the mbsystem. 


(3.4.3) GRIDDING 

Gridding for the bathymetry data are carried out using the HIPS software 
version 5.4 (CARIS, Canada). Firstly, low-quality data during the CTD cast and 
the ship's drift are removed. Secondly, spikes in the data are removed by 
"Surface Cleaning" function of the software with following parameters. 
     Tiling: by size (Minimum size of tile: 163.84 [m]) 
     Degree of polynomial: 1 (tiled plane) 
     Cleaning 
          Shallow threshold: 1.000, sigma = 68.26 [%] 
          Deep threshold: 1.000, sigma = 68.26 [%] 
          Minimum residual required for rejection: 10.000 [m] 
Thirdly, remaining erroneous data are manually removed and normal data, which 
have been removed by the "Surface Cleaning" function, are manually recovered by 
"Swath Editor" and "Subset Editor" functions of the software. Finally, the 
bathymetry data are gridded by "Interpolate" function of the software with 
following parameters. 
     Matrix size: 5 x 5 
     Number of nearneighbors: 18 


REFERENCE 

Mackenzie, K.V. (1981): Nine-term equation for the sound speed in the oceans, 
    J. Acoust. Soc. Am., 70 (3), pp 807-812. 



2.2 SURFACE METEOROLOGICAL OBSERVATION 
    (27 September 2006)
 

(1) PERSONNEL 
    Kunio Yoneyama (JAMSTEC)
    Yasutaka Imai (GODI)
    Shinya Okumura (GODI)
    Ryo Ohyama (GODI)
    Norio Nagahama (GODI)


(2) OBJECTIVE 

As a basic dataset that describes weather conditions during the cruise, surface 
meteorological observation was continuously conducted. 


(3) METHODS 

There are two different surface meteorological observation systems on the R/V 
MIRAI. One is the MIRAI surface meteorological measurement station (SMET), and 
the other is the Shipboard Oceanographic and Atmospheric Radiation (SOAR) 
system. 

Instruments of SMET whose data are used here are listed in Table 2.2.1. All 
SMET data were collected and processed by KOAC-7800 weather data processor made 
by Koshin Denki, Japan. Note that although SMET contains rain gauge, anemometer 
and radiometers in their system, we adopted those data from not SMET but SOAR 
due to the following reasons; 1) Since SMET rain gauge is located near the base 
of the mast, there is a possibility that its capture rate might be affected 
(the location possibly affect on the accuracy of the capture rate of the 
gauge), 2) SOAR's anemometer has better starting threshold wind speed (1 m/sec) 
comparing to SMET's anemometer (2 m/sec), and 3) SMET's radiometers record data 
with 10 W/m2 unit, while SOAR takes 1 W/m2 unit. 

SOAR system was designed and constructed by the Brookhaven National Laboratory 
(BNL), USA, for an accurate measurement of solar radiation on the ship. Details 
of SOAR can be found at http://www.gim.bnl.gov/soar/. 

SOAR consists of 1) Portable Radiation Package (PRP) that measures short and 
long wave downwelling radiation, 2) Zeno meteorological system that measures 
pressure, air temperature, relative humidity, wind speed/direction, and 
rainfall, and 3) Scientific Computer System (SCS) developed by the National 
Oceanic and Atmospheric Administration (NOAA), USA, for data collection, 
management, real-time monitoring, and so on. Information on sensors used here 
is listed in Table 2.2.2. 


Table 2.2.1. Instruments and locations of SMET. 
____________________________________________________________________________________
                                                              Location/
 Sensor         Parameter         Manufacturer/type           height from sea level 
 -------------  ----------------  --------------------------  ---------------------
 Thermometer*1  air temperature   Vaisala, Finland/HMP45A     compass deck*2/  21 m 
                relative humidity     
 Thermometer    sea temperature   Koshin Denki, Japan/RFN1-0  4th deck      /  -5 m 
 Barometer      pressure          Yokogawa, Japan/F-451       captain deck  /  13 m 
____________________________________________________________________________________
  *1 Gill aspirated radiation shield 43408 made by R. M. Young, USA is attached. 
  *2 There are two thermometers at starboard and port sides. 


Table 2.2.2. Instruments and locations of SOAR. 
_________________________________________________________________________________
                                                           Location/
 Sensor      Parameter              Manufacturer/type      height from sea level 
 ----------  ---------------------  ---------------------  ---------------------
 Anemometer  wind speed/direction   R.M. Young, USA/05106  foremast/      25 m 
 Rain gauge  rainfall accumulation  R.M. Young, USA/50202  foremast/      24 m 
 Radiometer  short wave radiation   Eppley, USA/PSP        foremast/      25 m 
             long wave radiation    Eppley, USA/PIR        foremast/      25 m 
_________________________________________________________________________________


(4) DATA PROCESSING AND DATA FORMAT 

All raw data were recorded every 6 seconds. Datasets produced here are 1-minute 
mean values (time stamp at the beginning of the average). They are simple mean 
of 8 samples (10 samples minus maximum/minimum values) to exclude singular 
values. Liner interpolation onto missing values was applied only when their 
interval is less than 4 minutes. 

Since the thermometers are equipped on both starboard/port sides on the deck, 
we used air temperature/relative humidity data taken at upwind side. Dew point 
temperature was produced from relative humidity and air temperature data. 

No adjustment to sea level values is applied except pressure data. 

Data are stored as ASCII format and contains following parameters. Time in UTC 
expressed as YYYYMMDDHHMM, time in Julian day (1.0000 = January 1, 0000Z), 
longitude (°E), latitude (°N), pressure (hPa), air temperature (°C), dew point 
temperature (°C), relative humidity (%), sea surface temperature (°C), zonal 
wind component (m/sec), meridional wind component (m/sec), precipitation 
(mm/hr), downwelling shortwave radiation (W/m2), and downwelling longwave 
radiation (W/m2). 

Missing values are expressed as "9999". 


(5) DATA QUALITY 

To ensure the data quality, each sensor was calibrated as follows. Since there 
is a possibility for fine time resolution data sets to have some noises caused 
(generated) by turbulence, it is recommended to filter them out (ex. hourly 
mean) from this 1-minute mean data sets depending on the scientific purpose. 

T/RH sensor: 
Temperature and humidity probes were calibrated before/after the cruise by the 
manufacturer. Certificated accuracy of T/RH sensors are better than ± 0.2°C and 
± 2%, respectively. 

We also checked T/RH values using another calibrated portable T/RH sensor 
(Vaisala, HMP45A) before and after the cruise. The results are as follows. 

Temperature (°C)
    Mean difference between T (SMET) and T (portable) is
        -0.3 ± 0.1 (°C) at port side, -0.2 ± 0.4 (°C) at starboard side.
Relative Humidity (%)
    Mean difference between RH (SMET) and RH (portable) is
        0 ± 1 (%) at port side, 0 ± 0 (%) at starboard side.

PRESSURE SENSOR: 
Using calibrated portable barometer (Vaisala, Finland/PTB220, certificated 
accuracy is better than ± 0.1 hPa), pressure sensor was checked before/after 
the cruise. Mean difference of SMET pressure sensor and portable sensor is 
0.0 ± 0.1 hPa. 

ANEMOMETER: 
Using digital tester (Hioki, Japan/3805), post calibration was conducted by the 
GODI. 
    Post-calibration date: Sep. 7, 2005 
    Starting threshold wind speed: 0.9 m/sec for clockwise 
                              0.9 m/sec for counter-clockwise
    Wind direction check:better than ± 2°
        Set  value       6  36  64  96  126  156  185  215  244  275  306  336  
        Measured  value  6  30  68  97  127  156  186  216  245  275  306  337
        Difference       0   0  -4  -1   -1    0   -1   -1   -1    0    0   -1

PRECIPITATION: 
Before the cruise, we put water into the rain gauge to check their linearity 
between the indicated values and water amount input. Expected accuracy is 
better than ± 1 mm corresponding to the sensor's specification. The results are 
as follows, and data were corrected using this relationship. 

                                               1st    2nd    3rd   Mean 
            -------------------------------  -----  -----  -----  -----
            minimum input water volume (cc)    0.0    0.0    0.0    0.0
            minimum measured value (mm)        0.7    0.7    0.8    0.8
            maximum input water volume (cc)  516.0  514.5  513.0  514.5
            maximum measured value (mm)       51.2   51.1   51.2   51.2

RADIATION SENSORS: 
Short wave and long wave radiometers were calibrated by the manufacturer, 
Remote Measurement and Research Company, USA, prior to the cruise. 


(6) DATA PERIODS 

1200 UTC, May 26, 2006-2300 UTC, July 1, 2006
Only SST data is available from 1230 UTC, May 26, 2006.


(7) POINT OF CONTACT 

Kunio Yoneyama (yoneyamak@jamstec.go.jp)
JAMSTEC/IORGC, 2-15, Natsushima, Yokosuka 237-0061, Japan 


2.3 THERMOSALINOGRAPH AND RELATED MEASUREMENTS 
    (22 January 2004)

 
(1) PERSONNEL 
    Takayoshi Seike (MWJ)
    Takeshi Kawano (JAMSTEC)


(2) OBJECTIVE 

To measure salinity, temperature, dissolved oxygen, and fluorescence of near-
sea surface water. 


(3) METHODS 

Continuous Sea Surface Water Monitoring System (Nippon Kaiyo Co., Ltd.) has six 
kinds of sensors and can automatically and continuously measure salinity, 
temperature, dissolved oxygen, fluorescence and particle size of plankton in 
near-sea surface water every 1-minute. This system is located in "sea surface 
monitoring laboratory" on R/V Mirai and connected to shipboard LAN-system. 
Measured data is stored in a hard disk of PC every 1-minute together with time 
and position of the ship, and displayed in the data management PC machine. 

Near-surface water was continuously pumped up to the laboratory and flowed into 
the Continuous Sea Surface Water Monitoring System through a vinyl-chloride 
pipe. The flow rate for the system is controlled by several valves and is set 
at 12 l/min except with fluorometer (about 0.3 l/min). The flow rate is 
measured with two flow meters and each value is checked every day. 

Specification of the each sensor in this system is listed below. 

a) Temperature and Salinity sensors 
   SEACAT THERMOSALINOGRAPH 
   Model:              SBE-21, Sea-Bird Electronics, Inc. 
   Serial number:      2126391-2641 
   Measurement range:  Temperature -5 to +35°C Salinity 0 to 6.5 S m-1 
   Accuracy:           Temperature 0.01°C 6 month-1 
   Resolution:         Salinity 0.001 S m-1 month-1 Temperatures 0.001°C 
                       Salinity 0.0001 S m-1 

b) Bottom of ship thermometer 
   Model:              SBE 3S, Sea-Bird Electronics, Inc. 
   Serial number:      032175 
   Measurement range:  -5 to +35°C 
   Resolution:         ± 0.001°C 
   Stability:          0.002°C year-1 
   
c) Dissolved oxygen sensor           
   Model:              2127A, Oubisufair Laboratories Japan Inc. 
   Serial number:      44733 
   Measurement range:  0 to 14 ppm 
   Accuracy:           ± 1% at 5°C of correction range 
   Stability:          1% month-1 
   
d) Fluorometer           
   Model:              10-AU-005, Turner Designs 
   Serial number:      5562 FRXX 
   Detection limit:    5 ppt or less for chlorophyll-a 
   Stability:          0.5% month-1 of full scale 
   
e) Particle Size sensor 
   Model:              P-05, Nippon Kaiyo Co., Ltd.
   Serial number:      P5024 
   Measurement range:  0.02681 mm to 6.666 mm 
   Accuracy:           ±10% of range 
   Reproducibility:    ±5% 
   Stability:          5% week-1 

f) Flow meter 
   Model:              EMARG2W, Aichi Watch Electronics Ltd. 
   Serial number:      8672 
   Measurement range:  0 to 30 l min-1 
   Accuracy:           ±1% 
   Stability:          ±1% day-1 
   
The monitoring periods (UTC) are listed below. 
26-Mar-05 13:31 to 30-Jun-05 02:45 


(4) COMPARISON OF SALINITY DATA WITH SAMPLED SALINITY 

We sampled seawater for salinity measurement about twice a day for salinity 
sensor calibration. All salinity samples were collected from the course of the 
system while on station or from regions with weak horizontal gradients. All 
samples were analyzed on Guildline 8400B. The results were shown in Table 
2.3.1. 


Table 2.3.1. Comparison of salinity between data obtained from Continuous Sea 
             Surface Water  Monitoring and collected samples. 
             _____________________________________________________

                             Time       Salinity  Bottle Salinity 
              Date [UTC]     [UTC]        data       [PSS-78] 
              ---------      -----      --------  ---------------
              27-Mar-05      22:52      32.9296      32.9317 
              28-Mar-05      12:36      33.6424      33.6306 
              28-Mar-05      22:55      33.3806      33.3756 
              29-Mar-05      06:12      33.6521      33.6319 
              29-Mar-05      22:46      33.3896      33.3984 
              30-Mar-05      18:49      34.5657      34.5776 
              30-Mar-05      22:54      34.4765      34.4939 
              31-Mar-05      04:22      34.5199      34.5350 
              31-Mar-05      22:40      34.4629      34.4929 
               1-JUN-05      12:36      34.4079      34.4531 
               1-JUN-05      22:51      34.4860      34.5147 
               2-JUN-05      05:02      34.4708      34.4911 
               3-JUN-05      02:53      34.5825      34.6117 
               3-JUN-05      09:01      34.5986      34.6273 
               4-JUN-05      02:47      34.6163      34.6446 
               5-JUN-05      02:38      34.6549      34.6750 
               5-JUN-05      15:56      34.6632      34.6873 
               6-JUN-05      02:31      34.4601      34.5024 
               6-JUN-05      15:43      34.3304      34.3552 
               7-JUN-05      02:36      34.3558      34.3859 
               7-JUN-05      16:51      34.8104      34.8351 
               8-JUN-05      02:40      34.5198      34.5394 
               8-JUN-05      18:19      34.8639      34.8893 
               9-JUN-05      02:48      34.4874      34.5868 
               9-JUN-05      15:44      34.7581      34.8940 
              10-JUN-05      02:42      35.0075      35.0049 
              10-JUN-05      15:24      34.9980      35.0406 
              11-JUN-05      02:30      34.6205      34.6298 
              12-JUN-05      08:20      34.5390      34.5625 
              12-JUN-05      14:32      34.5394      34.5688 
              13-JUN-05      00:17      34.5725      34.6049 
              13-JUN-05      14:34      34.9744      35.0077 
              14-JUN-05      04:12      34.7980      34.8137 
              14-JUN-05      14:48      34.8969      34.9322 
              15-JUN-05      03:32      34.5539      34.5324 
              15-JUN-05      14:49      34.4052      34.4381 
              16-JUN-05      01:33      34.4143      34.4526 
              16-JUN-05      14:43      34.4642      34.5038 
              17-JUN-05      02:51      34.2650      34.3030 
              17-JUN-05      14:47      34.4193      34.4256 
              18-JUN-05      00:59      34.1001      34.1407 
              18-JUN-05      14:46      33.9444      33.9876 
              19-JUN-05      00:47      33.8548      33.8967 
              19-JUN-05      14:28      33.8954      33.9374 
              20-JUN-05      00:37      33.9928      34.0371 
              20-JUN-05      14:29      33.9209      33.9624 
              21-JUN-05      02:56      33.9359      33.9764 
              21-JUN-05      14:48      33.9013      33.9045 
              22-JUN-05      01:18      33.8159      33.9168 
              22-JUN-05      14:47      34.1404      34.2044 
              23-JUN-05      00:52      34.2102      34.2569 
              23-JUN-05      14:32      34.2208      34.2785 
              24-JUN-05      01:01      33.9716      34.0119 
              24-JUN-05      12:51      34.1161      34.1624 
              25-JUN-05      00:35      34.1160      34.1664 
              25-JUN-05      14:45      34.0914      34.1350 
              26-JUN-05      00:26      34.0454      34.1016 
              26-JUN-05      15:21      34.2297      34.2773 
              27-JUN-05      04:11      34.1533      34.1756 
              27-JUN-05      14:38      34.1362      34.2077 
             ___________________________________________________



2.4 UNDERWAY pCO2 
    (31 August, 2006)
 

(1) PERSONNEL 
    Akihiko Murata (IORGC, JAMSTEC)
    Fuyuki Shibata (MWJ)
    Mikio Kitada (MWJ)
    Taeko Ohama (MWJ)
    Yoshiko Ishikawa (MWJ)


(2) INTRODUCTION 

Concentrations of CO2 in the atmosphere are now increasing at a rate of 1.5 
ppmv y-1 due to human activities such as burning of fossil fuels, 
deforestation, cement production, and so on. It is an urgent task to estimate 
as accurately as possible the absorption capacity of the ocean against the 
increased atmospheric CO2, as well as to clarify the mechanism of CO2 
absorption, because the magnitude of predicted global warming depends on the 
levels of CO2 in the atmosphere, and the ocean currently absorbs 1/3 of the 6 
Gt of carbon emitted into the atmosphere each year by human activities. 

In the P10 revisit cruise, we aimed to quantify how much anthropogenic CO2 is 
absorbed in the surface ocean of the North Pacific. For the purpose, we 
measured pCO2 (partial pressures of CO2) in the atmosphere and in the surface 
seawater. 


(3) APPARATUS AND SHIPBOARD MEASUREMENT 

Continuous underway measurements of atmospheric and surface seawater pCO2 were 
made with CO2 measuring system (Nippon ANS, Ltd) installed in the R/V Mirai of 
JAMSTEC. The system comprises of a non-dispersive infrared gas analyzer (NDIR; 
BINOS(r) model 4.1, Fisher-Rosemount), an air-circulation module and a 
showerheadtype equilibrator. To measure concentrations (mole fraction) of CO2 
in dry air (xCO2a), air sampled from the bow of the ship (approx. 30 m above 
the sea level) was introduced into the NDIR through a dehydrating route with an 
electric dehumidifier (kept at ~2°C), a Perma Pure dryer (GL Sciences Inc.), 
and a chemical desiccant (Mg(ClO4)2). The flow rate of the air was 500 ml min-
1. To measure surface seawater concentrations of CO2 in dry air (xCO2s), the 
air equilibrated with seawater within the equilibrator was introduced into the 
NDIR through the same flow route as the dehydrated air used in measuring xCO2a. 
The flow rate of the equilibrated air was 600 - 800 ml min-1. The seawater was 
taken by a pump from an intake placed at approx. 4.5 m below the sea surface. 
The flow rate of seawater in the equilibrator was 500 - 800 ml min-1. 

The CO2 measuring system was set to repeat the measurement cycle such as 4 
kinds of CO2 standard gases (Table 2.4.1), xCO2a (twice), xCO2s (7 times). This 
measuring system was run automatically throughout the cruise by a PC control. 


(4) QUALITY CONTROL 

Concentrations of CO2 of the standard gases are listed in Table 2.4.1, which 
were calibrated by JAMSTEC primary standard gases. The CO2 concentrations of 
the primary standard gases were calibrated by C.D. Keeling of the Scripps 
Institution of Oceanography, La Jolla, CA, USA. 

Since differences of concentrations of the standard gases between before and 
after the cruise were allowable 

(<0.1 ppmv), the averaged concentrations (Table 2.4.1) were adopted for 
subsequent calculations. 

In actual shipboard observations, signals of NDIR usually reveal a trend. The 
trend was adjusted linearly using signals of the standard gases analyzed before 
and after the sample measurements. 

Effects of water temperature increased between the inlet of surface seawater 
and the equilibrator on xCO2s were adjusted based on Gordon and Jones (1973), 
although the temperature increases were slight, being ~ 0.3°C. 

We checked values of xCO2a and xCO2s by examining signals of NDIR on recorder 
charts, and by plotting the xCO2a and xCO2s as a function of sequential day, 
longitude, sea surface temperature and sea surface salinity. 


Table 2.4.1.  Concentrations of CO2 standard gases used in the P10 revisit 
              cruise. 
                    ______________________________________

                     Cylinder no.   Concentrations (ppmv)
                     ------------   --------------------- 
                       CQB17639            262.94 
                       CQB09291            320.42 
                       CQB09292            381.04 
                       CQB09293            420.76 
                    ______________________________________


REFERENCE 

Gordon, L. I. and L. B. Jones (1973): The effect of temperature on carbon 
    dioxide partial pressure in seawater. Mar. Chem., 1, 317-322. 



2.5  Acoustic Doppler Current Profiler
     (23 August 2006)
 

(1) PERSONNEL 
    Yasushi Yoshikawa (JAMSTEC)
    Shinya Kouketsu (JAMSTEC) 
    Yasutaka Imai (GODI)
    Shinya Okumura (GODI)
    Ryo Ohyama (GODI) 


(2) INSTRUMENT AND METHOD 

The instrument used was an RDI 76.8 kHz unit, hull-mounted on the centerline 
and approximately 23 m aft of the bow at the water line. The firmware version 
was 5.59 and the data acquisition software was RDI VMDAS Version. 1.4. 
Operation was made from the first CTD station to the last CTD station. The 
instrument was used in water-tracking mode during the most of operations, 
recording each ping raw data in 8 m x 90 bin from about 23 m to 735 m in depth. 
Typical sampling interval was 3.5 seconds. Bottom track mode was added in the 
northernmost shallow water region. GPS gave navigation data. Two kinds of 
compass data were recorded. One compass was the ship's gyrocompass, which is 
connected the ADCP system directory, and its data were stored with the ADCP 
data. Current field based on the gyrocompass was used to check the operation 
and the performance on board. Another compass used was Inertial Navigation Unit 
(INU), DRU-H, Honeywell Inc. Its accuracy is 1.0 mile (about 0.056 degree) and 
had already set on zero bias before the beginning of the cruise. The INU 
compass data were stored independently, and combined with the ADCP data after 
the cruise. 


(3) PERFORMANCE AND QUICK VIEW OF THE ADCP DATA ON BOARD 

The performance of the ADCP instrument was almost good throughout the cruise: 
on streaming, profiles usually reached about 600 m (652384 pings of all 953103 
pings till June, 27). Profiles were sometimes rather bad on CTD station. The 
profiles did not reach so far, from 200 m to 500 m and the ADCP signal was 
typically weak at about 350 m in depth. It is probably due to babbles from the 
bow-thruster. Echo intensity was relatively weak in the sea south of 35°N in 
the subtropical and tropical North Pacific. It is probably due to weak 
reflection of the echo. The performance of the ADCP was relatively bad on 
streaming in these regions. 

We processed the ADCP data in this cruise on board as described below. ADCP-
coordinate velocities were converted to the earth-coordinate velocities using 
the ship's heading, roll and pitch data form the INU. The earth-coordinate 
currents were obtained by subtracting ship velocities from the earth-coordinate 
velocities. The ship velocities were obtained from the moving distances for 5 
minutes, which were measured by GPS data. The noise of the GPS position data 
was filtered out by 15-sec running mean. The errors of the estimated ship 
velocities are within 10 cm/s. The currents obtained in this cruise were shown 
in the preliminary report on the ship (figures are not shown here). 

After this cruise the parameters of the misalignment and the scale factor would 
be evaluated by using the bottom track data obtained both in this cruise and in 
the engineering test cruise made just before this cruise. 


(4) DATA PROCESSING 

Corrections of the misalignment and the scale factor were made after the cruise 
using the bottom track data. The bottom track data used was obtained during the 
engineering test cruise carried out just before the P10_revisit cruise. The 
misalignment angle calculated was 0.05 degree and the scale factor was 0.975. 
These parameters were similar to those calculated in August 2003. Criteria for 
the correlation less than 64 and error velocity more than 20 mm/s are removed 
here. Therefore the error is estimated at 20 mm/s. 

Raw data are filtered using the median filter on every 3 minutes. There are 
about 90 data in one ensemble. In vertical direction, 3 bins data are used, 
which would mean 24 m averaging in the filtering process. Time series of upper 
25 bins average flow are calculated using the 3 minutes sub set. The continuity 
of the series is examined in order to use each to average on the CTD sites and 
on streaming between the sites. Typically, the time series of the flow are 
stable on the CTD sites, where the standard deviation is 38 mm/s. The 
variability is likely to correspond to the temporal tidal motion. The data of 
almost all time stamps are used for averaging. On the other hand, the time 
series of that on streaming between the CTD sites are somewhat irregular, where 
the standard deviation is 63 mm/s. It is likely to be due to the variability in 
space with temporal tidal motion. The mismatch between the ship velocity 
obtained from the GPS and water column velocity of ADCP was found when the ship 
was accelerated and/or decelerated. Available time stamp was found using the 
continuity of the time series when the ship speed was almost constant. In the 
averaging process, we use the 40% criterion of the maximum frequency. In the 
next step, we averaged the subset at each CTD station and at streaming between 
the stations. Each mean profile is calculated with depth correction using the 
CTD data. Vertical grids are put on every 20 m. Available frequency for 
averaging was set as 40% of the most counts. It concludes almost good 
continuity of the vertical profile. 

Following is the features of the analyzed dataset. The mean available depth 
range is 642 m on the CTD stations and 576 m on streaming, respectively. There 
are non-available layer in the subsurface around 350 m between 10°N and 23°N. 
It appears more on streaming case, and sometimes the subsurface hole connects 
to the deeper non-available depth. The reason of the appearing hole should be 
the weak signal of reflection, which is associated with the meridional 
structure or distribution of the reflector. The available depth range is full 
in the subtropical region between 25°N and 35°N. Standard deviation of the flow 
is 4.0 cm/s and 6.4 cm/s. They are almost same of those of sub-set. Vertical 
profile of the standard deviation is similar to each other, except of the bias. 
It is shown in Fig B. The value is relative bigger where the strong flow 
exists, especially around 29°N, 23°N, 19°N and 8°N. 


(5) CURRENT DISTRIBUTIONS OBSERVED 

Current fields at 100 m is shown in Fig 6 (p.97). The major currents were 
clearly observed by the ADCP; the Oyashio, the Kuroshio Extension and the 
equatorial currents. The Oyashio appeared near the southern coast off the 
Hokkaido. The southern westward current was barotropic and it penetrated the 
deepest layer measured. The Kuroshio Extension existed around 36°N across the 
ship track. The maximum speed near the sea surface was 1.8 m/s at 36°22'N. 
The southern shift of the maximum speed with depth was observed; the maximum 
speed at 600 m depth was 0.5 m/s at 35°52'N. The eddy-like flow pattern 
appeared in the mixed water region between the Oyashio and the Kuroshio 
Extension. The westward flow was dominant in the south of the Kuroshio 
Extension. The flow was almost barotropic in the subtropical region. However, 
the flow showed baroclinic feature in the region between 5°N and 20°N. The 
North Equatorial Current was seen around 10°N. The Equatorial Counter Current 
was seen between 1°N and 6°N. The eastward flow of the Equatorial Under Current 
distributed just north of the equator, whose core appeared at 240 m at 1°53'N 
with a zonal speed of 0.79 cm/s. On the other hand, the core of the meridional 
component existed around the equator clearly. It might be an eddy or a meander 
feature of the current. The South Equatorial Current was seen from the equator 
to the southern hemisphere. The strong current along the coast was observed 
near the coast of the Papua New Guinea. 


(6) DATA STRUCTURE 

The record structure of the data set A, where file name is 'ADCP_A', is 
described below. The file consists of 259 profiles, 130 of the CTD sites and 
129 of the streaming. Each profile consists of header and data. The header has 
three lines representing analyzed site, date and time, and position. The data 
has 35 layers in which depth, zonal velocity, meridional velocity, and standard 
error of each grid are stored. Unit of depth is in meter. Unit of flow is in 
m/s. On the CTD station, the CTD station name (e.g. '143_1') is recorded as the 
analyzed site in the header. Mean time and position were calculated and 
recorded using the ADCP profiles during the CTD operation was made. On the way 
to next CTD station, hyphened two CTD station names (e.g. '143_1-142_1') are 
recorded as the analyzed site in the header. Recorded time and position are 
mean for the available ADCP profiles. The '99.999' in the data represents no 
available data stored. 

[data structure of the data set A] 
 Line 1: header 1
  Column 01-10: cruise code 
  Column 12-15: WHP line name 
  Column 17-27: analyzed site 
 Line 2: header 2
  Column 01-10: date (mm/dd/yyyy)
  Column 12-16: time (hh:mm) 
 Line 3: header 3
  Column 01-09: latitude (deg,min,N/S)
  Column 11-20: longitude (deg,min,E/W)
 Line 4-38: flow data in each depth level
  Column 01-05: depth (m) 
  Column 07-12: zonal velocity (m/s) 
  Column 14-19: meridional velocity (m/s) 
  Column 21-26: standard error (m/s) 

[data structure of the data set B: every 3 minutes] 
 Line 1: header 1 
  Column 01-10: cruise code 
  Column 12-15: WHP line name 
  Column 17-27: analyzed site 
 Line 2: header 2 
  Column 01-10: date (mm/dd/yyyy) 
  Column 12-16: time (hh:mm) 
 Line 3: header 3 
  Column 01-09: latitude (deg,min,N/S) 
  Column 11-20: longitude (deg,min,E/W) 
 Line 4-38: flow data in each depth level 
  Column 01-05: depth (m) 
  Column 07-12: zonal velocity (m/s) 
  Column 14-19: meridional velocity (m/s) 
  Column 21-26: standard error (m/s) 

Flow data processed in every three minutes are stored in the data set B, where 
the file name is 'ADCP_B'. The data structure is the same as that of the data 
set B, except for the analyzed site in the header 1. Sequential number is 
written in the record as `E$$$$$'. 



3 HYDROGRAPHIC MEASUREMENT TECHNIQUES AND CALIBRATIONS

3.1 CTD/O2 MEASUREMENTS 
    (25 October 2005)
 

(1) PERSONNEL 
    Hiroshi Uchida (JAMSTEC)
    Masao Fukasawa (JAMSTEC)
    Satoshi Ozawa (MWJ)
    Naoko Takahashi (MWJ)
    Kentaro Oyama (MWJ)
    Tomohide Noguchi (MWJ)


(2) WINCH ARRANGEMENTS 

The CTD package was deployed by using 4.5 Ton Traction Winch System (Dynacon, 
Inc., USA), which was installed on the R/V Mirai in April 2001. The CTD 
Traction Winch System with the Heave Compensation Systems (Dynacon, Inc., USA) 
is designed to reduce cable stress resulting from load variation caused by wave 
or vessel motion. The system is operated passively by providing a nodding boom 
crane that moves up or down in response to line tension variations. Primary 
system components include a complete CTD Traction Winch System with up to 10 km 
of 9.53 mm armored cable (Ocean Cable and Communication Co.), a cable rocker 
and Electro-Hydraulic Power Unit, a nodding-boom crane assembly, two hydraulic 
cylinders and two hydraulic oil/nitrogen accumulators mounted within a single 
frame assembly. The system also contains related electronic hardware interface 
and a heave compensation computer control program. 


(3) OVERVIEW OF THE EQUIPMENT 

The CTD system, SBE 911plus system (Sea-Bird Electronics, Inc., USA), is a real 
time data system with the CTD data transmitted from a SBE 9plus underwater unit 
via a conducting cable to the SBE 11plus deck unit. 

The SBE 11plus deck unit is a rack-mountable interface which supplies DC power 
to underwater unit, decodes serial data stream, formats data under 
microprocessor control, and passes the data to a companion computer. The serial 
data from the underwater unit is sent to the deck unit in RS-232 NRZ format 
using a 34,560 Hz carrier-modulated differential-phase-shift-keying (DPSK) 
telemetry link. The deck unit decodes the serial data and sends them to a 
personal computer to display, at the same time, to storage in a disk file using 
SBE SEASOFT software. 

The SBE 911plus system acquires data from primary, secondary and auxiliary 
sensors in the form of binary numbers corresponding to the frequency or the 
voltage outputs from those sensors at 24 samples per second. The calculations 
required to convert raw data to engineering units of the parameters are 
performed by the SBE SEASOFT in real-time. The same calculations can be carried 
out after the observation using data stored in a disk file. 

The SBE 911plus system controls 36-position SBE 32 Carousel Water Sampler. The 
Carousel accepts 12-litre water sample bottles. Bottles are fired through the 
RS-232C modem connector on the back of the SBE 11plus deck unit while acquiring 
real time data. The 12-litre Niskin-X water sample bottle (General Oceanics, 
Inc., USA) is equipped externally with two stainless steel springs. The 
external springs are ideal for applications such as trace metal analysis 
because the inside of the sampler is free from contaminants from springs. 

SBE's temperature (SBE 3) and conductivity (SBE 4) sensor modules were used 
with the SBE 9plus underwater unit fixed by a single clamp and "L" bracket to 
the lower end cap. The conductivity cell entrance is co-planar with the tip of 
the temperature sensor's protective steel sheath. The pressure sensor is 
mounted in the main housing of the underwater unit and is ported to outside 
through the oil-filled plastic capillary tube. A compact, modular unit 
consisting of a centrifugal pump head and a brushless DC ball bearing motor 
contained in an aluminum underwater housing pump (SBE 5T) flushes water through 
sensor tubing at a constant rate independent of the CTD's motion. Motor speed 
and pumping rate (3,000 rpm) remain nearly constant over the entire input 
voltage range of 12-18 volts DC. Flow speed of pumped water in standard TC duct 
is about 2.4 m/s. SBE's dissolved oxygen sensor (SBE 43) was placed between the 
conductivity sensor module and the pump. Auxiliary sensors, Deep Ocean 
Standards Thermometer (SBE 35), altimeter and fluorometer, were also used with 
the SBE 9plus underwater unit. The SBE 35 position in regard to the SBE 3 is 
shown in Figure 3.1.1. 

It is known that the CTD temperature data is influenced by motion (pitching and 
rolling) of the CTD package. In order to reduce the motion of the CTD package, 
a heavy stainless frame (total weight of the CTD package without sea water in 
the bottles is about 1,000 kg) was used and an aluminum plate (54 x 90 cm) was 
attached to the frame (Figure 3.1.1). 

Summary of the system used in this cruise 

Deck unit: 
  SBE, Inc., SBE 11plus, S/N 0308 
Under water unit: 
  SBE, Inc., SBE 9plus, S/N 79511 (Pressure sensor: S/N 0677) 
Temperature sensor: 
  SBE, Inc., SBE 3, S/N 1464 (primary) 
  SBE, Inc., SBE 3, S/N 1525 (secondary) 
Conductivity sensor: 
  SBE, Inc., SBE 4, S/N 1203 (primary) 
  SBE, Inc., SBE 4, S/N 3036 (secondary, from P10N_143 to P10_53) 
  SBE, Inc., SBE 4, S/N 1088 (secondary, from P10_52 to P10_27) 
  SBE, Inc., SBE 4, S/N 2854 (secondary, from P10_26 to P10_1) 
Oxygen sensor: 
  SBE, Inc., SBE 43, S/N 0391 (primary, from P10N_143 to P10N_122) 
  SBE, Inc., SBE 43, S/N 0767 (primary, from P10N_121 to P10_1) 
  SBE, Inc., SBE 43, S/N 0390 (secondary) 
Pump: 
  SBE, Inc., SBE 5T, S/N 3118 (primary) 
  SBE, Inc., SBE 5T, S/N 3293 (secondary) 
Altimeter: 
  Benthos Inc., PSA-916T, S/N 1157 
Deep Ocean Standards Thermometer: 
  SBE, Inc., SBE 35, S/N 0045 
Fluorometer: 
  Seapoint sensors, Inc., S/N 2579 
  (without fluorometer from P10N_134 to 132, P10N_112 to P10_68, and P10_28 to 1) 
Carousel Water Sampler: 
  SBE, Inc., SBE 32, S/N 0278 
Water sample bottle: 
  General Oceanics, Inc., 12-litre Niskin-X (no TEFLON coating) 



(4) PRE-CRUISE CALIBRATION 


(4.1) PRESSURE 

The Paroscientific series 4000 Digiquartz high pressure transducer 
(Paroscientific, Inc., USA) uses a quartz crystal resonator whose frequency of 
oscillation varies with pressure induced stress with 0.01 per million of 
resolution over the absolute pressure range of 0 to 15,000 psia (0 to 10,332 
dbar). Also, a quartz crystal temperature signal is used to compensate for a 
wide range of temperature changes at the time of an observation. The pressure 
sensor (MODEL 415K-187) has a nominal accuracy of 0.015% FS (1.5 dbar), typical 
stability of 0.0015% FS/month (0.15 dbar/month) and resolution of 0.001% FS 
(0.1 dbar). 

Pre-cruise sensor calibrations were performed at SBE, Inc., USA. The following 
coefficients were used in the SEASOFT: 

S/N 0677, 2 July 2002 
  c1 = -62072.94c2 = -1.176956
  c3 = 1.954420e-02
  d1 = 0.027386d2 = 0.0
  t1 = 30.05031
  t2 = -4.744833e-04
  t3 = 3.757590e-06
  t4 = 3.810700e-09
  t5 = 0.0

Pressure coefficients are first formulated into
  c = c1 + c2 * U + c3 * U2 
  d = d1+ d2* U 
  t0= t1 + t2 * U + t3 * U2 + t4 * U3 + t5* U4 

where U is temperature in degrees Celsius. The pressure temperature, U, is 
determined according to
  U (°C) = M * (12 bit pressure temperature compensation word) - B 

The following coefficients were used in SEASOFT: 
S/N 0677 
  M = 0.0128041
  B = -9.324136
  (in the underwater unit system configuration sheet dated on 22 February 2002)

Finally, pressure is computed as 
  P (psi) = c * [1 - (t02/t2)] * {1 - d * [1 - (t02/t2)]} 

where t is pressure period (msec). Since the pressure sensor measures the 
absolute value, it inherently includes atmospheric pressure (about 14.7 psi). 
SEASOFT subtracts 14.7 psi from computed pressure above automatically. 

Pressure sensor calibrations against a dead-weight piston gauge (Bundenberg 
Gauge Co. Ltd., UK; Model 480DA, S/N 23906) are performed at JAMSTEC (Yokosuka, 
Kanagawa, JAPAN) by Marine Works Japan Ltd. (MWJ), usually once in a year in 
order to monitor sensor time drift and linearity. The pressure sensor drift is 
known to be primarily an offset drift at all pressures rather than a change of 
span slope. The pressure sensor hysterisis is typically 0.2 dbar. The following 
coefficients for the sensor drift correction were also used in SEASOFT: 

S/N 0677, 13 April 2005 
  slope = 0.9998953
  offset = -0.44425 
The drift-corrected pressure is computed as 
  Drift-corrected pressure (dbar) = slope * (computed pressure in dbar) + offset 

Result of the pressure sensor calibration against the dead weight piston gauge 
is shown in Figure 3.1.2. Time drift of the pressure sensor based on the offset 
and the slope of the calibrations is also shown in Figure 3.1.3. 


(4.2) TEMPERATURE (SBE 3) 

The temperature sensing element is a glass-coated thermistor bead in a 
stainless steel tube, providing a pressure-free measurement at depths up to 
10,500 (6,800) meters by titanium (aluminum) housing. The sensor output 
frequency ranges from approximately 5 to 13 kHz corresponding to temperature 
from -5 to 35°C. The output frequency is inversely proportional to the square 
root of the thermistor resistance, which controls the output of a patented Wien 
Bridge circuit. The thermistor resistance is exponentially related to 
temperature. The SBE 3 thermometer has a nominal accuracy of 0.001°C, typical 
stability of 0.0002°C/month and resolution of 0.0002°C at 24 samples per 
second. The premium temperature sensor, SBE 3plus, is a more rigorously tested 
and calibrated version of standard temperature sensor (SBE 3). A sensor is 
designated as an SBE 3plus only after demonstrating drift of less than 0.001°C 
during a six-month screening period. In addition, the time response is 
carefully measured and verified to be 0.065 ± 0.010 seconds. 

Pre-cruise sensor calibrations were performed at SBE, Inc., USA. The following 
coefficients were used in SEASOFT: 

S/N 1464 (primary), 19 April 2005 
  g = 4.84385804e-03
  h = 6.80766786e-04
  i = 2.69831319e-05
  j = 2.13061451e-06
  f0 = 1000.000

S/N 1525 (secondary), 19 April 2005 
  g = 4.84608198e-03
  h = 6.75358139e-04
  i = 2.65523364e-05
  j = 2.13525896e-06
  f0 = 1000.000

Temperature (ITS-90) is computed according to 
  Temperature (ITS-90) = 
    1/{g + h * [ln(f0/f)] + i * [ln2(f0/ f)] + j * [ln3(f0/f)]} - 273.15 

where f is the instrument frequency (kHz). 
  
Time drift of the SBE 3 temperature sensors based on the laboratory calibrations 
is shown in Figure 3.1.4. 


(4.3) CONDUCTIVITY (SBE 4) 

The flow-through conductivity sensing element is a glass tube (cell) with three 
platinum electrodes to provide in-situ measurements at depths up to 10,500 
meters. The impedance between the center and the end electrodes is determined 
by the cell geometry and the specific conductance of the fluid within the cell. 
The conductivity cell composes a Wien Bridge circuit with other electric 
elements of which frequency output is approximately 3 to 12 kHz corresponding 
to conductivity of the fluid of 0 to 7 S/m. The SBE 4 has a nominal accuracy of 
0.0003 S/m, typical stability of 0.0003 S/m/month and resolution of 0.00004 S/m 
at 24 samples per second. 

Pre-cruise sensor calibrations were performed at SBE, Inc., USA. The following 
coefficients were used in 

SEASOFT: 

S/N 1203 (primary), 19 April 2005 
  g = -4.05393563e+00
  h = 4.93901550e-01
  i = 1.74707654e-05
  j = 2.56674141e-05
  CPcor = -9.57e-08 (nominal)
  CTcor = 3.25e-06 (nominal)

S/N 3036 (secondary), 20 January 2005 
  g = -1.03104164e+01
  h = 1.42680631e+00
  i = 2.61243729e-04
  j = 5.17689837e-05
  CPcor = -9.57e-08 (nominal)
  CTcor = 3.25e-06 (nominal)

S/N 1088 (secondary), 10 March 2005 
  g = -4.21020837e+00
  h = 5.77013782e-01
  i = -1.87512042e-04
  j = 4.10775826e-05
  CPcor = -9.57e-08 (nominal)
  CTcor = 3.25e-06 (nominal)

S/N 2854 (secondary), 22 June 2004 
  g = -1.02670783e+01 
  h = 1.41649193e+00 
  i = -3.19882205e-04 
  j = 7.82222198e-05 
  CPcor = -9.57e-08 (nominal) 
  CTcor = 3.25e-06 (nominal) 

Conductivity of a fluid in the cell is expressed as: 
  C (S/m) = (g + h * f 2 + i * f 3 + j * f 4)/[10 ( 1 + CTcor * t + CPcor * p)] 

where f is the instrument frequency (kHz), t is the water temperature (°C) and 
p is the water pressure (dbar). The value of conductivity at salinity of 35, 
temperature of 15°C (IPTS-68) and pressure of 0 dbar is 4.2914 S/m. 


(4.4) OXYGEN (SBE 43) 

The SBE 43 oxygen sensor uses a Clark polarographic element to provide in-situ 
measurements at depths up to 7,000 meters. Calibration stability is improved by 
an order of magnitude, and pressure hysterisis is largely eliminated in the 
upper ocean (1,000 m) compared with the previous oxygen sensor (SBE 13). 
Continuous polarization eliminates wait-time for stabilization after power-up. 
Signal resolution is increased by on-board temperature compensation. The oxygen 
sensor is also included in the path of pumped sea water. The oxygen sensor 
determines dissolved oxygen concentration by counting the number of oxygen 
molecules per second (flux) that diffuse through a membrane, where the 
permeability of the membrane to oxygen is a function of temperature and ambient 
pressure. Computation of dissolved oxygen in engineering units is done in 
SEASOFT software. The range for dissolved oxygen is 120% of surface saturation 
in all natural waters; nominal accuracy is 2% of saturation; typical stability 
is 2% per 1,000 hours. 

Pre-cruise sensor calibrations were performed at SBE, Inc., USA. The following 
coefficients were used in SEASOFT: 

S/N 0391 (primary), 8 April 2005 
  Soc = 0.3525
  Offset = -0.4761
  TCor = 0.0010
  PCor = 1.350e-04
  
S/N 0767 (primary), 11 February 2005
 Soc = 0.4320 
  Offset = -0.4889 
  TCor = 0.0002 
  PCor = 1.350e-04 

S/N 0390 (secondary), 8 April 2005
  Soc = 0.3567 
  Offset = -0.4965
  TCor = 0.0013 
  PCor = 1.350e-04 
  Oxygen (ml/l) is computed as 

  Oxygen (ml/l) = {Soc * (v + Offset)} * exp(TCor * t + PCor * p) * Oxsat(t, s) 
  Oxsat(t, s) = exp[A1 + A2 * (100/t) + A3 * ln(t/100) + A4 * (t/100) 
    + s * {B1 + B2 * (t/100) + B3 * (t/100) * (t/100)}]
  A1 = -173.4292
  A2 = 249.6339
  A3 = 143.3483
  A4 = -21.8482
  B1 = -0.033096
  B2 = -0.00170

where p is pressure in dbar, t is absolute temperature and s is salinity in 
psu. Oxsat is oxygen saturation value minus the volume of oxygen gas (STP) 
absorbed from humidity-saturated air. 


(4.5) DEEP OCEAN STANDARDS THERMOMETER 

Deep Ocean Standards Thermometer (SBE 35) is an accurate, ocean-range 
temperature sensor that can be standardized against Triple Point of Water and 
Gallium Melt Point cells and is also capable of measuring temperature in the 
ocean to depths of 6,800 m. 

Temperature is determined by applying an AC excitation to reference resistances 
and an ultrastable aged thermistor with a drift rate of less than 0.001°C/year. 
Each of the resulting outputs is digitized by a 20-bit A/D converter. The 
reference resistor is a hermetically sealed, temperature-controlled VISHAY. The 
switches are mercury wetted reed relays with a stable contact resistance. AC 
excitation and ratiometric comparison using a common processing channel removes 
measurement errors due to parasitic thermocouples, offset voltages, leakage 
currents, and gain errors. Maximum power dissipated in the thermistor is 0.5 
µwatts, and contributes less than 200 µK of overheat error. 

The SBE 35 communicates via a standard RS-232 interface at 300 baud, 8 bits, no 
parity. The SBE 35 can be used with the SBE 32 Carousel Water Sampler and SBE 
911plus CTD system. The SBE 35 makes a temperature measurement each time when a 
bottle fire confirmation is received, and stores the value in EEPROM. 
Calibration coefficients stored in EEPROM allow the SBE 35 to transmit data in 
engineering units. Commands can be sent to SBE 35 to provide status display, 
data acquisition setup, data retrieval, and diagnostic test by using terminal 
software. 

Following the methodology used for standards-grade platinum resistance 
thermometers (SPRT), calibration of the SBE 35 is accomplished in two steps. 
The first step is to characterize and capture the non-linear resistance vs 
temperature response of the sensor. The SBE 35 calibrations are performed at 
SBE, Inc., in a low-gradient temperature bath and against ITS-90 certified 
SPRTs maintained at Sea-Bird's primary temperature metrology laboratory. The 
second step is frequent certification of the sensor by measurements in 
thermodynamic fixed-point cells. Triple point of water (TPW) and gallium melt 
point (GaMP) cells are appropriate for the SBE 35. The SBE 35 resolves 
temperature in the fixed-point cells to approximately 25 µK. Like SPRTs, slow 
time drift of the SBE 35 is adjusted by a slope and offset correction to the 
basic non-linear calibration equation. 

Pre-cruise sensor calibrations were performed at SBE, Inc., USA. The following 
coefficients were stored in 

EEPROM: 

S/N 0045, 27 October 2002 (1st step: linearization) 
  a0 =  5.84093815e-03
  a1 = -1.65529280e-03
  a2 =  2.37944937e-04
  a3 = -1.32611385e-05
  a4 =  2.83355203e-07

Linearized temperature (ITS-90) is computed according to 
  Linearized temperature (ITS-90) = 
    1/{a0 + a1 * [ln(n)] + a2 * [ln2(n)] + a3 * [ln3(n)]+ a4 * [ln4(n)]} - 273.15 

where n is the instrument output. Then the SBE 35 is certified by measurements 
in thermodynamic fixed-point cells of the TPW (0.0100°C) and GaMP (29.7646°C). 
Like SPRTs, the slow time drift of the SBE 35 is adjusted by periodic 
recertification corrections. 

S/N 0045, 6 May 2005 (2nd step: fixed point calibration) 
  Slope = 1.000019 
  Offset = -0.000881 

Temperature (ITS-90) is calibrated according to 
  Temperature (ITS-90) = Slope * Linearized temperature + Offset 

The SBE 35 has a time constant of 0.5 seconds. The time required per sample = 
1.1 * NCYCLES + 2.7 seconds. The 1.1 seconds is total time per an acquisition 
cycle. NCYCLES is the number of acquisition cycles per sample. The 2.7 seconds 
is required for converting the measured values to temperature and storing 
average in EEPROM. Root mean square (rms) temperature noise for a SBE 35 in a 
Triple Point of Water cell is typically expressed as 82/NCYCLES1/2 in µK. In 
this cruise NCYCLES was set to 4 and the rms noise is estimated to be 0.04 m°C. 

When using the SBE 911 system with the SBE 35, the deck unit receives incorrect 
signal from the under water unit for confirmation of firing bottle #16. In 
order to correct the signal, a module (Yoshi Ver. 1, EMS Co. Ltd., 
JAPAN) was used between the under water unit and the deck unit.

Time drift of the SBE 35 based on the fixed point calibrations is shown in 
Figure 3.1.5.


(4.6) ALTIMETER 

Benthos PSA-916T Sonar Altimeter (Benthos, Inc., USA) determines the distance 
of the target from the unit by generating a narrow beam acoustic pulse and 
measuring the travel time for the pulse to bounce back from the target surface. 
The PSA-916T is the same as the standard PSA-916 Sonar Altimeter except that it 
is housed in a corrosion-resistant titanium pressure case. It is O-ring-sealed 
and rated for operation in water depths up to 10,000 meters. In this unit, a 
250 microseconds pulse at 200 kHz is transmitted 5 times in a second. The PSA-
916T uses the nominal speed of sound of 1,500 m/s. Thus the unit itself, 
neglecting variations in the speed of sound, can be considered accurate to 5% 
or 0.1 meter, whichever is greater. In the PSA-916T the jitter of the detectors 
is approximately 5 microseconds or ± 0.4 cm total distance. Since the total 
travel time is divided by two, the jitter error is ± 0.2 cm. 

The following scale factors were used in SEASOFT: 

S/N 1157 
  FSVolt * 300/FSRange = 15 
  Offset = 0.0 


(4.7) FLUOROMETER 

The Seapoint Chlorophyll Fluorometer (Seapoint sensors, Inc., USA) is a high-
performance, low power instrument to provide in-situ measurements of 
chlorophyll-a at depths up to 6,000 meters. The instrument uses modulated blue 
LED lamps and a blue excitation filter to excite chlorophyll-a. The fluorescent 
light emitted by the chlorophyll-a passes through a red emission filter and is 
detected by a silicon photodiode. The low level signal is then processed using 
synchronous demodulation circuitry, which generates an output voltage 
proportional to chlorophyll-a concentration. 

The following coefficients were used in SEASOFT: 

S/N 2579 
  Gain = 30 
  Offset = 0.0

Chlorophyll-a concentration is computed as 
  Chlorophyll-a (µg/l) = (Voltage * 30/Gain) + Offset 



(5) DATA COLLECTION AND PROCESSING 

(5.1) DATA COLLECTION 

CTD measurements were made by using a SBE 9plus equipped with two pumped 
temperature-conductivity (TC) sensors. The TC pairs were monitored to check 
drift and shifts by examining the differences between the two pairs. A 
dissolved oxygen sensor was placed between the conductivity sensor module and 
the pump. Auxiliary sensors included Deep Ocean Standards Thermometer, 
altimeter and fluorometer. The SBE 9plus (sampling rate of 24 Hz) was mounted 
horizontally in a 36-position carousel frame. 

CTD system was powered on at least two minutes in advance of the operation and 
was powered off at least two minutes after the operation in order to acquire 
pressure data on the ship's deck. 

The package was lowered into the water from the starboard side and held 10 m 
beneath the surface for about one minute in order to activate the pump. After 
the pump was activated, the package was lifted to the surface and lowered at a 
rate of 1.0 m/s to 200 m then the package was stopped in order to operate the 
heave compensator of the crane. The package was lowered again at a rate of 1.2 
m/s to the bottom. The position of the package relative to the bottom was 
monitored by the altimeter reading. Also the bottom depth was monitored by the 
SEABEAM multi-narrow beam sounder on board. For the up cast, the package was 
lifted at a rate of 1.2 m/s except for bottle firing stops. At each bottle 
firing stops, the bottle was fired after waiting from the stop for 30 seconds 
and the package was stayed 5 seconds for measurement of the Deep Ocean 
Standards Thermometer. At 200 m from the surface, the package was stopped in 
order to stop the heave compensator of the crane. 

Water samples were collected using a 36-bottle SBE 32 Carousel Water Sampler 
with 12-litre Nisken-X bottles. Before a cast taken water for CFCs, the 36-
bottle frame and Niskin-X bottles were wiped with acetone. 

The SBE 11plus deck unit received the data signal from the CTD. Digitized data 
were forwarded to a personal computer running the SEASAVE data acquisition 
software. Temperature, conductivity, salinity, oxygen and descent rate profiles 
were displayed in real-time with the package depth and altimeter reading. 
Differences in temperature salinity and oxygen between primary and secondary 
sensor were also displayed in order to monitor the status of the sensors. 

Data acquisition software 
SBE, Inc., SEASAVE-Win32, version 5.27b 


(5.2) DATA COLLECTION PROBLEMS 

At station P10N_142, bottle #1 did not fire at the beginning of the up cast. 
The first cast was aborted and Y-cable was replaced. 

At station P10N_137, the primary temperature showed abnormal values at depths 
between 450 and 430 dbar in the up cast. The connecting cable and connector for 
the primary temperature sensor was checked and cleaned. 

At station P10N_122, the primary oxygen sensor was replaced because the 
difference between the sensor output and the bottle oxygen was gradually 
becoming greater (40 µmol/kg near the bottom). 

At station P10N_113, the primary temperature data was slightly noisy during up 
cast. And at station P10N_112, the primary temperature signal was lost near the 
bottom. The connecting cable for the temperature sensor was replaced after the 
cast. 

At station P10N_101 and 100, the secondary temperature and conductivity were 
very noisy from the up cast of P10N_101 because of something in the secondary 
TC duct. The TC duct was flushed well after the cast. 

At station P10_62, the CTD signal was lost at 1,270 dbar in the down cast and 
the cast was aborted. The second cast was carried out after re-connecting the 
armored cable and pigtail. 

At station P10_53, the secondary conductivity was abnormally biased near the 
bottom. The conductivity sensor was replaced after the cast. 

At station P10_27, the secondary conductivity was abnormally biased near the 
bottom. The conductivity sensor was replaced after the cast. 


(5.3) DATA PROCESSING 

SEASOFT consists of modular menu driven routines for acquisition, display, 
processing, and archiving of oceanographic data acquired with SBE equipment, 
and is designed to work with a compatible personal computer. Raw data are 
acquired from instruments and are stored as unmodified data. The conversion 
module DATCNV uses the instrument configuration and calibration coefficients to 
create a converted engineering unit data file that is operated on by all 
SEASOFT post processing modules. Each SEASOFT module that modifies the 
converted data file adds proper information to the header of the converted file 
permitting tracking of how the various oceanographic parameters were obtained. 
The converted data is stored in rows and columns of ASCII numbers. The last 
data column is a flag field used to mark scans as good or bad. 

The followings are the SEASOFT data processing module sequence and 
specifications used in the reduction of CTD data in this cruise. 


DATA PROCESSING SOFTWARE 
  SBE, Inc., SEASOFT-Win32, version 5.27b 

DATCNV converted the raw data to scan number, pressure, depth, temperatures, 
conductivities, oxygen voltage, descent rate, altitude and fluorescence. DATCNV 
also extracted bottle information where scans were marked with the bottle 
confirm bit during acquisition. 

The duration was set to 4.4 seconds, and the offset was set to 0.0 seconds. 

ROSSUM created a summary of the bottle data. The bottle position, date, time 
were output as the first two columns. Scan number, pressure, depth, 
temperatures, conductivities, oxygen voltage, descent rate, altitude and 
fluorescence were averaged over 4.4 seconds. And salinity, potential 
temperature, density (σθ) and oxygen were computed. 

ALIGNCTD converted the time-sequence of conductivity and oxygen sensor outputs 
into the pressure sequence to ensure that all calculations were made using 
measurements from the same parcel of water. For a SBE 9plus CTD with the ducted 
temperature and conductivity sensors and a 3,000-rpm pump, typical net advance 
of the conductivity relative to the temperature is 0.073 seconds. So, the SBE 
11plus deck unit was set to advance the primary and the secondary conductivity 
for 1.73 scans (1.75/24 = 0.073 seconds). Oxygen data are also systematically 
delayed with respect to depth mainly because of the long time constant of the 
oxygen sensor and of an additional delay from the transit time of water in the 
pumped plumbing line. This delay was compensated by 6 seconds advancing oxygen 
sensor output (oxygen voltage) relative to the temperature. 

WILDEDIT marked extreme outliers in the data files. The first pass of WILDEDIT 
obtained an accurate estimate of the true standard deviation of the data. The 
data were read in blocks of 1000 scans. Data greater than 10 standard 
deviations were flagged. The second pass computed a standard deviation over the 
same 1000 scans excluding the flagged values. Values greater than 20 standard 
deviations were marked bad. This process was applied to all variables. 

CELLTM used a recursive filter to remove conductivity cell thermal mass effects 
from the measured conductivity. Typical values used were thermal anomaly 
amplitude alpha = 0.03 and the time constant 1/beta = 7.0. 

FILTER performed a low pass filter on pressure with a time constant of 0.15 
seconds. In order to produce zero phase lag (no time shift) the filter runs 
forward first then backwards. 

WFILTER performed a median filter to remove spikes in the Fluorometer data. A 
median value was determined from a window of 49 scans. 

SECTION selected a time span of data based on scan number in order to reduce a 
file size. The minimum number was set to be the start time when the CTD package 
was beneath the sea-surface after activation of the pump. The maximum number 
was set to be the end time when the package came up from the surface. Data for 
estimation of the CTD pressure drift were prepared before SECTION. 

LOOPEDIT marked scans where the CTD was moving less than the minimum velocity 
of 0.0 m/s (traveling backwards due to ship roll). 

DERIVE was used to compute oxygen. 

BINAVG averaged the data into 1-dbar pressure bins. The center value of the 
first bin was set equal to the bin size. The bin minimum and maximum values are 
the center value plus and minus half the bin size. Scans with pressures greater 
than the minimum and less than or equal to the maximum were averaged. Scans 
were interpolated so that a data record could exist every dbar. 

DERIVE was re-used to compute salinity, potential temperature, and density (σθ). 

SPLIT was used to split data into the down cast and the up cast. 

Remaining spikes in the salinity data were manually eliminated for the raw 
data. When number of data in the 1dbar-pressure bin was less than 10, the data 
of the bin was not used. For remaining spikes in the Fluorometer data near 
surface, quality flags of the Fluorometer data were set to 4. Remaining spikes 
in the oxygen data were eliminated for a 1-dbar averaged data when the 
difference between original data and low-pass (7-dbar median) filtered data was 
greater than or equal to 0.003 (voltage) at the pressure level greater or equal 
to 1,200 dbar (1,150 dbar for station X03). The data gap over 1-dbar was 
linearly interpolated with a quality flag of 6. 


(6) POST-CRUISE CALIBRATION 

(6.1) PRESSURE 

The CTD pressure sensor offset in the period of the cruise is estimated from 
the pressure readings on the ship deck. For best results the Paroscientific 
sensor has to be powered for at least 10 minutes before the operation and 
carefully temperature equilibrated. However, CTD system was powered only 
several minutes before the operation at most of stations. In order to get the 
calibration data for the pre- and post-cast pressure sensor drift, the CTD deck 
pressure is averaged over first and last two minutes, respectively. Then the 
atmospheric pressure deviation from a standard atmospheric pressure (14.7 psi) 
is subtracted from the CTD deck pressure. The atmospheric pressure was measured 
at the captain deck (20 m high from the base line) and sub-sampled one-minute 
interval as a meteorological data. Time series of the CTD deck pressure is 
shown in Figure 3.1.6. 

The CTD pressure sensor offset is estimated from the deck pressure obtained 
above. Mean of the pre- and the post-casts data over the whole period gave an 
estimation of the pressure sensor offset from the pre-cruise calibration. Mean 
residual pressure between the dead weight piston gauge and the calibrated CTD 
data at 0 dbar of the pre-cruise calibration is subtracted from the mean deck 
pressure. Offset of the pressure data is estimated to be -0.40 dbar (Table 
3.1.1). So the post-cruise correction of the pressure data is not deemed 
necessary for the pressure sensor. 


Table 3.1.1. Offset of the pressure data. Mean and standard deviations are 
             calculated from time series of the average of the pre- and the 
             post-cast deck pressures. 
______________________________________________________________________________

 S/N   Mean deck        Standard          Residual pressure  Estimated offset 
       Pressure (dbar)  deviation (dbar)  (dbar)             (dbar) 
 ----  ---------------  ----------------  -----------------  ----------------
 0677  -0.42            0.05              -0.02              -0.40 
______________________________________________________________________________  


(6.2) TEMPERATURE 

The CTD temperature sensor (SBE 3) is made with a glass encased thermistor bead 
in a needle. The needle protects the thermistor from seawater. If the 
thermistor bead is slightly large of specification it receives mechanical 
stress when the needle is compressed at high pressure (Budeus and Schneider, 
1998). The pressure sensitivity for a SBE 3 sensor is usually less than +2 
m°C/6000 dbar. It is somewhat difficult to measure this effect in the 
laboratory and it the difficulty is one of the primary reasons to use the SBE 
35 at sea for critical work. Also SBE 3 measurements may be affected by viscous 
heating (about +0.5 m°C) that occurs in a TC duct and does not occur for un-
pumped SBE 35 measurements (Larson and Pederson, 1996). Furthermore, the SBE 35 
calibrations have some uncertainty (about 0.2 m°C) and SBE 3 calibrations have 
some uncertainty (about 1 m°C). So the practical corrections for CTD 
temperature data can be made by using a SBE 35, correcting the SBE 3 to agree 
with the SBE 35 (a linear pressure correction, a viscous heating correction and 
an offset for drift and/or calibration uncertainty). 

Post-cruise sensor calibration for the SBE 35 was performed at SBE, Inc., USA. 

S/N 0045, 15 August 2005 (2nd step: fixed point calibration) 
  Slope = 1.000011
  Offset = -0.000973

Offset of the SBE 35 data from the pre-cruise calibration are estimated to be 
0.1 m°C for temperature less than 4°C. So the post-cruise correction of the SBE 
35 temperature data is not deemed necessary for the SBE 35.  

The discrepancy between the CTD temperature and the SBE 35 is considered to be 
a function of pressure and time. Effect of the viscous heating is assumed to be 
constant. Since the pressure sensitivity is thought to be constant in time at 
least during observation period, the CTD temperature is calibrated as 

             Calibrated temperature = T - (c0 * P + c1 * t + c2)

where T is CTD temperature in°C, P is pressure in dbar, t is time in days from 
pre-cruise calibration date of CTD temperature and c0, c1, and c2 are 
calibration coefficients. The best fit sets of coefficients are determined by 
minimizing the sum of absolute deviation from the SBE 35 data. The MATLAB(r) 
function FMINSEARCH is used to determine the sets. The FMINSEARCH uses the 
simplex search method (Lagarias et al., 1998). This is a direct search method 
that does not use numerical or analytic gradients. 

The calibration is performed for the primary and secondary temperature data. 
The CTD data created by the software module ROSSUM are used. The deviation of 
CTD temperature from the SBE 35 temperature at depth shallower than 2,000 dbar 
is large for determining the coefficients with sufficient accuracy since the 
vertical temperature gradient is too large in the regions. So the coefficients 
are determined using the data for the depth deeper than 1,950 dbar. 

The number of data used for the calibration and the mean absolute deviation 
from the SBE 35 are listed in Table 3.1.2 and the calibration coefficients are 
listed in Table 3.1.3. The results of the post-cruise calibration for the CTD 
temperature are summarized in Table 3.1.4 and shown in Figure 3.1.7 and 3.1.8. 

Basically, the secondary temperature data is used for the dataset. For the 
station P10N_101, P10N_100, P10_53 and P10_27, the primary temperature data is 
used instead of the secondary temperature data because the quality of the 
secondary conductivity data at these stations was bad. 


Table 3.1.2. Number of data used for the calibration (pressure >= 1,950 dbar) 
             and mean absolute deviation (ADEV) between the CTD temperature and 
             the SBE 35.
 _____________________________________________________________________________

  S/N   Number of data  ADEV (m°C)  Note 
  ----  --------------  ----------  -----------------------------------------
  1464  1586            0.10        for P10N_101, P10N_100, P10_53 and P10_27 
  1525  1583            0.10 
 _____________________________________________________________________________


Table 3.1.3. Calibration coefficients for the CTD temperature sensors. 
                     ________________________________________

                      S/N   c0(°C/dbar)  c1(°C/day)   c2(°C) 
                      ----  ----------   ---------   -------
                      1464  -1.0013e-7   2.4017e-6   0.56e-3 
                      1525  -7.9037e-9   2.8765e-6   0.29e-3 
                     ________________________________________


Table 3.1.4. Difference between the CTD temperature and the SBE 35 after the 
             post-cruise calibration. Mean and standard deviation (Sdev) are 
             calculated for the data below and above 1,950 dbar. Number of data 
             used is also shown. 
     _______________________________________________________________________

               Pressure >= 1,950 dbar             Pressure < 1,950 dbar 
      S/N   Num   Mean (m°C)  Sdev (m°C)        Num   Mean (m°C)  Sdev (m°C) 
      ----  ----  ----------  ----------       ----  -----------  ----------
      1464  1586     0.00        0.14          2171     -0.35         8.3 
      1525  1583     0.00        0.13          2153     -0.52         6.3 
     _______________________________________________________________________


(6.3) SALINITY 

The discrepancy between the CTD salinity and the bottle salinity is considered 
to be a function of conductivity and pressure. The CTD salinity is calibrated 
as 
        Calibrated salinity = S - (c0 * P + c1* C + c2* C * P + c3) 

where S is CTD salinity, P is pressure in dbar, C is conductivity in S/m and 
c0, c1, c2 and c3 are calibration coefficients. The best fit sets of 
coefficients are determined by minimizing the sum of absolute deviation with a 
weight from the bottle salinity data. The MATLAB(r) function FMINSEARCH is used 
to determine the sets. The weight is given as a function of vertical salinity 
gradient and pressure as 

     Weight = min[4, exp{log(4) * Gr/Grad}] * min[4, exp{log(4) * P2/PR2}] 

where Grad is vertical salinity gradient in PSU dbar-1, P is pressure in dbar. 
Gr and PR are threshold of the salinity gradient (0.5 mPSU dbar -1) and 
pressure (1,000 dbar), respectively. When salinity gradient is small (large) 
and pressure is large (small), the weight is large (small) at maximum (minimum) 
value of 16 (1). The salinity gradient is calculated using up-cast CTD salinity 
data. The up-cast CTD salinity data is low-pass filtered with a 3-point 
(weights are 1/4, 1/2, 1/4) triangle filter before the calculation. 

The calibration is performed for the salinity derived from the following 
conductivity sensor.

  Secondary (S/N 3036): from P10N_143 to P10_54 except for P10N_101 and P10N_100
  Secondary (S/N 1088): from P10_52 to P10_28
  Secondary (S/N 2854): from P10_26 to P10_1
  Primary   (S/N 1203): for P10N_101, P10N_100, P10_53 and P10_27
  
The CTD data created by the software module ROSSUM are used after the post-
cruise calibration for the CTD temperature. On stations P10N_101, P10N_100, 
P10_53 and P10_27, data quality of the secondary conductivity sensor was bad, 
so the data from the primary conductivity sensor are used for the stations. 

The coefficients are determined for some groups of the CTD station. The results 
of the post-cruise calibration for the CTD salinity are summarized in Table 
3.1.5 and shown in Figure 3.1.9. And the calibration coefficients and the 
number of the data (Num) used for the calibration are listed in Table 3.1.6. 


Table 3.1.5. Difference between the CTD salinity and the bottle salinity after 
             the post-cruise calibration. Mean and standard deviation (Sdev) 
             are calculated for the data below and above 1,000 dbar. Number of 
             data used is also shown. 
        ____________________________________________________________________

             Pressure >= 1,000 dbar              Pressure < 1,000 dbar
         Num   Mean (mPSU)  Sdev (mPSU)      Num   Mean (mPSU)  Sdev (mPSU)
         ----  -----------  -----------      ----  -----------  -----------
         2031     -0.03        0.50          1548     -0.38        15.6 
        ____________________________________________________________________
 

Table 3.1.6. Calibration coefficients for the CTD salinity. 
_______________________________________________________________________________________

 Stations (Num)        c0                c1               c2                c3 
 --------------  ---------------   ---------------  ----------------  ----------------
 143_1-122_1     1.0131034690e-5   8.0275830498e-4  -3.1419321824e-6  -1.7267523622e-4 
  (598) 
 121_1-102_1     1.1573101209e-6  -5.5651332935e-4  -4.1004021024e-7   4.8048881814e-3 
  (709) 
 101_1-100_1,    7.0963418115e-7  -1.4372272016e-3  -1.9540013620e-7   6.9910914220e-3 
 53_1,27_1(134) 
 99_1-61_1      -7.2653193556e-7  -4.6533749916e-4   1.6408648275e-7   3.6992027960e-3 
  (695) 
 60_1-54_1       4.2743744355e-6  -1.0727071488e-3  -1.3910765762e-6   5.0556686130e-3 
  (228) 
 52_1-40_1      -1.9442243171e-6  -2.9304615120e-3   6.6566837298e-7   1.0095656997e-2 
  (436) 
 39_1-28_1      -7.0071602987e-6  -3.1405026102e-3   2.2878224338e-6   1.0159646236e-2 
  (334) 
 26_1-1_1       -7.0377497246e-6  -2.4744338608e-3   2.1748120985e-6   1.0327699240e-2 
  (578) 
_______________________________________________________________________________________



(6.4) OXYGEN 

The CTD oxygen is calibrated using the oxygen model (see 3.1.3(4)) as 

Calibrated oxygen (ml/l) 
= {(Soc+dSoc) * {v+offset+doffset} * exp{(TCor+dTCor) * t + (PCor+dPCor) * p}} 
*Oxsat(t, s) 

where p is pressure in dbar, t is absolute temperature and s is salinity in 
psu. Oxsat is oxygen saturation value minus the volume of oxygen gas (STP) 
absorbed from humidity-saturated air (see 3.1.3(4)). Soc, offset, TCor and PCor 
are the pre-cruise calibration coefficients (see 3.1.3(4)), and dSoc, doffset, 
dTCor and dPCor are calibration coefficients. The best fit sets of coefficients 
are determined by minimizing the sum of absolute deviation with a weight from 
the bottle oxygen data. The MATLAB(r) function FMINSEARCH is used to determine 
the sets. The weight is given as a function of vertical oxygen gradient and 
pressure as 

     Weight = min[4, exp{log(4) * Gr/Grad}] * min[4, exp{log(4) * P2/PR2}] 

where Grad is vertical oxygen gradient in µmol kg-1 dbar-1, P is pressure in 
dbar. Gr and PR are threshold of the oxygen gradient (0.3 µmol kg-1 dbar-1) and 
pressure (1,000 dbar), respectively. When oxygen gradient is small (large) and 
pressure is large (small), the weight is large (small) at maximum (minimum) 
value of 16 (1). The oxygen gradient is calculated using up-cast CTD oxygen 
data. The up-cast CTD oxygen data is low-pass filtered with a 3-point (weights 
are 1/4, 1/2, 1/4) triangle filter before the calculation. 

The calibration is basically performed for the output from secondary oxygen 
sensor. On stations P10N_101 and P10N_100, data quality of the secondary oxygen 
sensor were bad, so the data from the primary oxygen sensor are used for the 
stations. The down-cast CTD data sampled at same density of the up-cast CTD 
data created by the software module ROSSUM are used after the post-cruise 
calibration for the CTD temperature and salinity. 

The coefficients are basically determined on each station. Some stations, 
especially on shallow stations, are grouped for determining the calibration 
coefficients. The results of the post-cruise calibration for the CTD oxygen are 
summarized in Table 3.1.7 and shown in Figure 3.1.10. And the calibration 
coefficients and number of the data used for the calibration are listed in 
Table 3.1.8. 


Table 3.1.7. Difference between the CTD oxygen and the bottle oxygen after the 
             post-cruise calibration. Mean and standard deviation (Sdev) are 
             calculated for the data below and above 1,000 dbar. Number of data 
             used is also shown. 
      ____________________________________________________________________

          Pressure >= 1,000 dbar                Pressure < 1,000 dbar 
               Mean        Sdev                      Mean        Sdev 
       Num   (µmol/kg)   (µmol/kg)          Num    (µmol/kg)   (µmol/kg) 
       ----  ---------   ---------          ----   ---------   ---------
       2091    -0.01       0.89             1586    -0.74        6.10 
      ____________________________________________________________________
 

Table 3.1.8. Calibration coefficients for the CTD oxygen. 
________________________________________________________________________________________

 Stations (Num)    dSoc              dTCor            dPCor             doffset 
 ----------------  ---------------   ---------------  ---------------   ---------------
 143_1-135_1(150)  8.4629646531e-3   5.8573110490e-5  8.5929128792e-6  -2.5296856384e-2 
 134_1 (33)        1.1267442718e-2  -6.2548916427e-3  3.5064120727e-6  -9.4194921754e-3 
 133_1 (35)        1.6126510125e-2   3.5398495888e-4  2.1736462754e-6  -1.4625220328e-2 
 132_1 (34)        2.3848796038e-2  -7.2897960077e-4  1.4777271150e-7  -1.7971132206e-2 
 131_1-130_1 (70)  2.5787931229e-2  -1.1510003784e-3  1.7500494703e-6  -2.5297499910e-2 
 129_1 (35)        2.5699254255e-2  -2.4457679187e-3  3.1376007240e-6  -2.8137637876e-2 
 128_1 (36)        2.7101839015e-2  -5.3160010276e-3  1.0471669748e-6  -2.1112173634e-2 
 127_1-124_1(140)  3.2771370687e-2  -1.4194990742e-3  4.3317721484e-7  -3.1264320130e-2 
 123_1 (34)        1.3461831314e-2   1.2534561726e-3  3.4977813378e-6  -1.1130414739e-2 
 122_1-121_1 (67)  2.4505139384e-2  -7.6774993155e-6  4.0666037955e-6  -1.9391470346e-2 
 120_1-118_1(106)  2.4393648003e-2   3.8668328581e-4  4.8139225402e-6  -2.2964168413e-2 
 117_1 (36)        6.4297501230e-2  -6.0748102232e-3  1.2321533791e-5  -4.3578232477e-2 
 116_1-115_1 (69)  6.1728950413e-2  -2.4236972142e-3  8.4116664417e-6  -2.8152202106e-2 
 114_1 (36)        7.0360855399e-2  -1.9473306036e-3  7.1904905368e-6  -3.4375305778e-2 
 113_1 (36)        5.7514523169e-2  -1.3251658263e-3  1.1702324658e-5  -2.8436450647e-2 
 112_2 (36)        6.1225526921e-2  -1.1296247021e-3  1.5631766694e-5  -2.7485442452e-2 
 111_1 (32)        7.3605378139e-2  -2.3174647896e-3  1.4955041317e-5  -3.2962769302e-2 
 110_1-109_1 (72)  7.9506816981e-2  -3.0313412311e-3  1.2917095934e-5  -2.9537356741e-2 
 108_1 (34)        7.4044802064e-2  -2.9826802903e-3  1.3439480159e-5  -2.3326579573e-2 
 107_1 (36)        8.4416077466e-2  -3.7442549024e-3  1.2133117223e-5  -2.8990559091e-2 
 106_1 (36)        8.1559536467e-2  -3.7947285403e-3  1.0482801323e-5  -2.1130113322e-2 
 105_1 (36)        7.7977171662e-2  -3.5083314252e-3  1.2290289395e-5  -2.1629039232e-2 
 104_1 (35)        9.2261453429e-2  -4.7148684849e-3  1.0265062864e-5  -2.8761859259e-2 
 103_1 (36)        8.8878333181e-2  -4.1826341574e-3  1.1136323966e-5  -2.8237527730e-2 
 102_1-99_1 (67)   9.9200594712e-2  -5.0484640984e-3  8.8915471090e-6  -3.1905045411e-2 
 101_1 (34)        3.0129338190e-1  -1.1653504238e-2  1.1882141679e-5  -1.9842437289e-2 
 100_1 (35)        2.7158568330e-1  -9.6766702665e-3  1.8657995745e-5  -1.6643920468e-2 
 98_1-97_1 (72)    8.9242241499e-2  -4.1223589541e-3  1.3047469365e-5  -3.0402717515e-2 
 X02_1 (35)        9.1123725963e-2  -4.2545430365e-3  1.2211179226e-5  -2.9045382383e-2 
 96_1 (36)         8.6671887501e-2  -2.7985557054e-3  1.4356440319e-5  -2.9380552239e-2 
 95_1 (35)         9.1098196385e-2  -4.1664253311e-3  1.3708853093e-5  -3.2666306600e-2 
 73_1 (34)         8.6129574441e-2  -3.5603954781e-3  1.4574878522e-5  -2.9862423005e-2 
 72_1 (35)         1.0036481344e-1  -5.1093500434e-3  1.1666319684e-5  -3.6207838465e-2 
 71_1 (36)         8.4173654695e-2  -3.8092086700e-3  1.1274443416e-5  -1.8669779770e-2 
 70_1 (36)         1.0186076918e-1  -5.1541833011e-3  9.1342978652e-6  -3.1135324237e-2 
 69_1-68_1 (72)    8.9917533040e-2  -3.9168184780e-3  1.5457399284e-5  -3.5731052554e-2 
 67_1-X03_1 (72)   9.1207184596e-2  -4.1992442894e-3  1.1874997453e-5  -2.7891215819e-2 
 66_1-57_1 (343)   9.3811168599e-2  -3.9222893217e-3  1.3665539977e-5  -3.4973063121e-2 
 56_1 (35)         8.3919270521e-2  -3.0577403931e-3  1.2497919350e-5  -2.3422736496e-2 
 55_1 (35)         6.3554451043e-2  -1.6679231971e-3  1.4967295161e-5  -5.8774789743e-3 
 54_1-53_1 (67)    7.9632995540e-2  -2.6792794668e-3  1.4076926317e-5  -2.4184137595e-2 
 52_1-50_1 (105)   1.0468035054e-1  -4.2252408010e-3  1.0992132766e-5  -4.3523806492e-2 
 49_1 (36)         1.0325878768e-1  -3.9694348381e-3  1.4354033024e-5  -5.2396627173e-2 
 48_1 (36)         9.2004545333e-2  -3.5974926447e-3  1.1472902153e-5  -3.3149352166e-2 
 47_1 (36)         1.0423026238e-1  -4.1495148297e-3  9.6837199865e-6  -4.0672124901e-2 
 46_1 (35)         1.0055879128e-1  -3.8195756827e-3  1.1737826935e-5  -4.4066183201e-2 
 45_1 (36)         9.9165776795e-2  -3.8067274203e-3  1.2457982576e-5  -4.3479339238e-2 
 44_1 (35)         9.4137904347e-2  -3.4233002647e-3  1.3312121974e-5  -3.9890841285e-2 
 X04_1 (35)        1.0425859813e-1  -3.9296966528e-3  1.2713132819e-5  -5.0123360653e-2 
 42_1 (30)         1.0867593096e-1  -4.1215117254e-3  1.0764968338e-5  -5.2204671557e-2 
 41_1-33_1 (237)   9.3225751360e-2  -3.2381566447e-3  1.4385618009e-5  -4.2285094417e-2 
 32_1-31_1 (62)    9.6439233248e-2  -3.7464841484e-3  1.2562011963e-5  -4.3757150045e-2 
 30_1-27_1 (124)   7.9094998661e-2  -2.3057878654e-3  1.4624201939e-5  -2.6435707440e-2 
 26_1-24_1 (94)    7.4299364827e-2  -2.1170662031e-3  1.5207952108e-5  -2.1468378127e-2 
 23_1-21_1 (96)    7.8997591888e-2  -2.2185575199e-3  1.6807682992e-5  -3.1972596525e-2 
 20_1-18_1 (86)    6.2467592016e-2  -1.2496499182e-3  1.6052290286e-5  -5.3975020163e-3 
 17_1-16_1 (60)    8.8214792922e-2  -2.7635515096e-3  1.4852006762e-5  -3.9218993513e-2 
 15_1-1_1 (253)    5.8505595375e-2  -7.9127988583e-4  2.4416439079e-5  -1.2472116837e-2 
________________________________________________________________________________________


REFERENCES 

Budeus, G. and W. Schneider (1998): In-situ temperature calibration: A remark 
    on instruments and methods, Intl. WOCE Newsletter, 30, 16-18. 

Lagarias, J.C., J.A. Reeds, M.H. Wright and P. E. Wright (1998): Convergence 
    properties of the Nelder-Mead simplex method in low dimensions, SIAM 
    Journal of Optimization, 9, 112-147. 

Larson, N. and A. Pederson (1996): Temperature measurements in flowing water: 
    Viscous heating of sensor tips, 1st IGHEM Meeting, Montreal, Canada. 
    (http://www.seabird.com/technical_references/paperindex.htm) 



3.2 SALINITY 
    (13 October 2006) 

(1) PERSONNEL 
    Takeshi Kawano (JAMSTEC)
    Fujio Kobayashi (MWJ)
    Kenichi Katayama (MWJ)
    Tatsuya Tanaka (MWJ)


(2) OBJECTIVES 
    Measurement of bottle salinities in order to calibrate CTD salinities and 
    to identify leaking bottles. 


(3) INSTRUMENT AND METHOD 

(3.1) SALINITY SAMPLE COLLECTION 

The bottles in which the salinity samples are collected and stored are 250 ml 
Phoenix brown glass bottles with screw caps. Each bottle was rinsed three times 
with sample water and was filled to the shoulder of the bottle. The caps were 
also thoroughly rinsed. Salinity samples were stored for about 12 hours in the 
same laboratory as the salinity measurement was made. 


(3.2) INSTRUMENTS AND METHOD 

The salinity analysis was carried out on Guildline Autosal salinometers model 
8400B (S/N 62556), which were modified by addition of an Ocean Science 
International peristaltic-type sample intake pump and two Guildline platinum 
thermometers model 9450. One thermometer monitored an ambient temperature and 
the other monitored a bath temperature. The resolution of the thermometers was 
0.001°C. The measurement system was almost same as Aoyama et al (2003). The 
salinometer was operated in a ship's laboratory air-conditioned at a bath 
temperature of 24°C. Ambient temperature varied from approximately 22°C to 
24°C, while bath temperature is very stable and varied within ± 0.002°C on rare 
occasion. A measure of a double conductivity ratio of a sample is taken as a 
median of thirty-one readings. Data collection was started after 5 seconds and 
it took about 10 seconds to collect 31 readings by a personal computer. Data 
were sampled for the sixth and the seventh filling of the cell. In case the 
difference in the double conductivity ratio between this two fillings was 
smaller than 0.00003, the average value of the two double conductivity ratios 
was used to calculate the bottle salinity with the algorithm for practical 
salinity scale, 1978 (UNESCO, 1981). If the difference was greater than or 
equal to 0.00003, we measured the eighth filling of the cell. In case the 
double conductivity ratio of the eighth filling did not satisfy the criteria 
above, we measured the ninth and the tenth filling of the cell and the median 
of the double conductivity ratios of these five fillings are used to calculate 
the bottle salinity. 

The measurement was conducted for about 16hours per day (typically from 7:00 to 
23:00) and the cell was cleaned with ethanol or soap or both after the 
measurement of the day. 


(3.3) PRELIMINARY RESULT 

Standard Seawater 

Standardization control was set to 491 and all the measurements were done by 
this setting. During the whole measurement, STANDBY was 5509 ± 0001 and ZERO 
was 0.00001. We used IAPSO Standard Seawater batch P145 whose conductivity 
ratio was 0.99981 (double conductivity ratio is 1.99962) as the standard for 
salinity. We measured 177 ampoules of P145. There were 5 bad bottles whose 
conductivities are extremely high or low. Data of these 5 bottles are not taken 
into consideration hereafter. 

Fig.3.2.1 shows the history of double conductivity ratio of the Standard 
Seawater batch P145. During this cruise, we did flushing the cell twice for 
cleaning using ultrasonic washing machine. The average of double conductivity 
ratio from Stn.143 to Stn.071 was 1.99962 and the standard deviation was 
0.00001, which is equivalent to 0.0002 in salinity. The average from Stn.070 to 
Stn.023 was 1.99963 and the standard deviation was 0.00001. We reduce 0.00001 
to the measured double conductivity ratio during this period. The average of 
double conductivity ratio from Stn.022 to Stn.001 was 1.99962 and the standard 
deviation was 0.00001, which is equivalent to 0.0002 in salinity. 

Sub-Standard Seawater 

We also used sub-standard seawater which was deep-sea water filtered by pore 
size of 0.45 micrometer and stored in a 20 liter cubitainer made of 
polyethylene and stirred for at least 24 hours before measuring. It was 
measured every six samples in order to check possible sudden drift of the 
salinometer. During the whole measurements, there was no detectable sudden 
drift of the salinometer. 

Replicate and Duplicate Samples 

We took 666 pairs of replicate samples and 55 pairs of duplicate samples. 
Figure 3.2.2 (a) and (b) show the histogram of the absolute difference among 
replicate samples and among duplicate ones, respectively. There were six bad 
measurements and 18 questionable measurements in replicate samples and six 
questionable measurements in duplicate samples. Excluding these bad and 
questionable measurements, the standard deviation of the absolute deference of 
642 pairs of replicate samples was 0.0002 in salinity and that of 48 pairs of 
duplicate samples was 0.0002 in salinity. The results of replicate samples were 
averaged and flagged as 6 in the seafile. 


REFERENCES 

Aoyama, M., T. Joyce, T. Kawano and Y. Takatsuki: Standard seawater comparison 
    up to P129. Deep-Sea Research, I, Vol. 49, 1103-1114, 2002 

UNESCO: Tenth report of the Joint Panel on Oceanographic Tables and Standards. 
    UNESCO Tech. Papers in Mar. Sci., 36, 25 pp., 1981 



3.3 OXYGEN 
    (17 October 2006) 


(1) PERSONNEL 
    Ikuo KANEKO (JAMSTEC)
    Yuichiro KUMAMOTO (JAMSTEC)
    Takayoshi SEIKE (MWJ)
    Ai YASUDA (MWJ)
    Kimiko NISHIJIMA (MWJ)


(2) OBJECTIVES 

Dissolved oxygen is a significant tracer for the ocean circulation study. 
Recent studies in the North Pacific indicated that dissolved oxygen 
concentration in intermediate layers decreased in basin wide scale during the 
past decades. The causes of the decrease, however, are still unclear. During 
MR05-02, we measured dissolved oxygen concentration from surface to bottom 
layers at all hydrocast stations. The stations from 29°N to 4°S reoccupied WHP 
P10 stations in 1993. Our purpose is to evaluate decadal change of dissolved 
oxygen in the western Pacific. 


(3) REGENT 

Pickling Reagent I: Manganous chloride solution (3M) 
Pickling Reagent II: Sodium hydroxide (8M)/sodium iodide solution (4M) 
Sulfuric acid solution (5M) 
Sodium thiosulfate (0.025M) 
Potassium iodate (0.001667M) 
CSK standard of potassium iodate: Lot ASE8280, Wako Pure Chemical 
  Industries Ltd., 0.0100N 


(4) INSTRUMENTS 

Burette for sodium thiosulfate; 
APB-510 manufactured by Kyoto Electronic Co. Ltd./10 cm3 of titration vessel 
Burette for potassium iodate; 
APB-410 manufactured by Kyoto Electronic Co. Ltd./20 cm3 of titration vessel 
Detector; Automatic photometric titrator manufactured, Kimoto Electronic Co. Ltd 


(5) SEAWATER SAMPLE 

Following procedure is based on a determination method in the WHP Operations 
Manual (Dickson, 1996). Seawater samples were collected from Niskin sampler 
bottles attached to the CTD-system. Seawater for bottle oxygen measurement was 
transferred from the Niskin sampler bottle to a volume calibrated glass flask 
(ca. 100 cm3). Three times volume of the flask of seawater was overflowed. 
Sample temperature was measured by a thermometer during the overflow. Then two 
reagent solutions (Reagent I, II) of 0.5 cm3 each were added immediately to the 
sample flask and the stopper was inserted carefully into the flask. The sample 
flask was then shaken vigorously to mix the contents and to disperse the 
precipitate finely and throughout. After the precipitate settled at least 
halfway down the flask, the flask was vigorously shaken again to disperse the 
precipitate. The sample flasks containing pickled samples were stored in a 
laboratory until they were titrated. 


(6) SAMPLE MEASUREMENT 

At least two hours after the re-shaking, the pickled samples were measured on 
board. A magnetic stirrer bar and 1 cm3 sulfuric acid solution were added to 
the sample flask and stirring began. Samples were titrated by with sodium 
thiosulfate solution whose molarity was determined by potassium iodate solution 
(section 3.3.6). Temperature of sodium thiosulfate during titration was 
recorded by a thermometer. During this cruise we measured dissolved oxygen 
concentration using two sets of the titration apparatus, DOT-1 and DOT-2. 
Dissolved oxygen concentration (µmol kg-1) was calculated by sample temperature 
during the sampling, CTD salinity, flask volume, and titrated volume of the 
sodium thiosulfate solution. 


(7) STANDARDIZATION 

Concentration of sodium thiosulfate titrant (ca. 0.025M) was determined by 
potassium iodate solution. Pure potassium iodate was dried in an oven at 130°C. 
1.7835 g potassium iodate accurately weighed An acculately weighted 1.7835 g of 
potassium iodate was dissolved in deionized water and diluted to final volume 
of 5 dm3 in a calibrated volumetric flask (0.001667M). 10 cm3 of the standard 
potassium iodate solution was added to a flask using a volume-calibrated 
dispenser. Then 90 cm3 of deionized water, 1 cm3 of sulfuric acid solution, and 
0.5 cm3 of pickling reagent solution II and I were added into the flask in 
order. Amount of titrated volume of sodium thiosulfate gave the molarity of the 
sodium thiosulfate titrant. Table 3.3.1 shows result of the standardization 
during this cruise. Error (C.V.) of the each standardization was less than 
0.08% (n = 5). 


(8) DETERMINATION OF THE BLANK 

The oxygen in the pickling reagents I (0.5 cm3) and II (0.5 cm3) was assumed to 
be 3.8 x 10-8 mol (Dickson, 1996). The blank from the presence of redox species 
apart from oxygen in the reagents (the pickling reagents I, II, and the 
sulfuric acid solution) was determined as follows. 1 and 2 cm3 of the standard 
potassium iodate solutions were added to two flasks respectively. Then 100 cm3 
of deionized water, 1 cm3 of sulfuric acid solution, and 0.5 cm3 of pickling 
reagent solution II and I were added to the two flasks in order. The blank was 
determined by difference between the two times of the first (1 cm3 of KIO3) 
titrated volume of the sodium thiosulfate and the second (2 cm3 of KIO3) one. 
The results of the blank determination are also shown in Table 3.3-1. The 
averaged blank of DOT-1 and DOT-2 were -0.007 and -0.010 cm3, respectively. 


Table 3.3.1. Results of the standardization and the blank determinations during MR05-02. 
____________________________________________________________________________________________________

    Date   |   |   KIO3      |        DOT-1 (cm3)        |        DOT-2 (cm3)        |   Samples 
   (UTC)   | # | bottle      |  Na2S2O3     E.P.   blank |  Na2S2O3     E.P.   blank |  (Stations)
 ----------|---|-------------|---------------------------|---------------------------|-------------
 2005/5/26 | 1 | 20050420-01 | 20050523-1  3.959  -0.006 | 20050523-2  3.961  -0.011 | 135-143 
 2005/5/28 |   | 20050420-02 | 20050523-1  3.960  -0.005 | 20050523-2  3.961  -0.008 | 131-134 
 2005/5/29 |   | 20050420-03 | 20050523-3  3.957  -0.008 | 20050523-4  3.961  -0.011 | 127-130 
 2005/5/30 |   | 20050420-04 | 20050523-3  3.960  -0.006 | 20050523-4  3.964  -0.008 | 123-126 
 2005/5/31 |   | 20050420-05 | 20050529-1  3.959  -0.006 | 20050529-2  3.961  -0.009 | 119-122 
 2005/6/02 |   | 20050420-06 | 20050529-1  3.959  -0.006 | 20050529-2  3.959  -0.009 | 115-118 
 2005/6/03 |   | 20050420-07 | 20050529-3  3.959  -0.007 | 20050529-4  3.960  -0.008 | 111-114 
 2005/6/04 |   | 20050420-08 | 20050529-3  3.958  -0.006 | 20050529-4  3.961  -0.009 | 107-110 
 2005/6/05 | 2 | 20050420-13 | 20050603-1  3.954  -0.007 | 20050603-2  3.957  -0.011 | 103-106 
 2005/6/06 |   | 20050420-14 | 20050603-1  3.956  -0.006 | 20050603-2  3.956  -0.011 | 99-102 
 2005/6/07 |   | 20050420-15 | 20050603-3  3.956  -0.007 | 20050603-4  3.958  -0.011 | 96,X02,97,98 
 2005/6/08 |   | 20050420-16 | 20050603-3  3.955  -0.008 | 20050603-4  3.959  -0.009 | 69-73,95 
 2005/6/10 |   | 20050420-17 | 20050609-1  3.953  -0.009 | 20050609-2  3.955  -0.010 | 66,X03,67,68 
 2005/6/10 |   | 20050420-17 | 20050609-1  3.961  -0.008 | 20050609-2  3.960  -0.011 | 67 
 2005/6/11 |   | 20050420-18 | 20050609-1  3.953  -0.005 | 20050609-2  3.955  -0.010 | 62-65 
 2005/6/13 |   | 20050420-19 | 20050609-3  3.952  -0.008 | 20050609-4  3.954  -0.009 | 58-61 
 2005/6/14 |   | 20050420-20 | 20050609-3  3.954  -0.008 | 20050609-4  3.956  -0.010 | 54-57 
 2005/6/16 | 3 | 20050420-25 | 20050613-1  3.951  -0.007 | 20050613-2  3.953  -0.009 | 50-53 
 2005/6/17 |   | 20050420-26 | 20050613-1  3.953  -0.006 | 20050613-2  3.954  -0.009 | 46-49 
 2005/6/18 |   | 20050420-27 | 20050613-3  3.953  -0.008 | 20050613-4  3.954  -0.010 | 42,X04,44,45 
 2005/6/19 |   | 20050420-28 | 20050613-3  3.953  -0.008 | 20050613-4  3.954  -0.008 | 36-41 
 2005/6/20 |   | 20050420-29 | 20050618-1  3.960  -0.008 | 20050618-2  3.962  -0.010 | 31-35 
 2005/6/21 |   | 20050420-30 | 20050618-1  3.960  -0.007 | 20050618-2  3.962  -0.010 | 27-30 
 2005/6/22 |   | 20050420-32 | 20050618-3  3.960  -0.009 | 20050618-4  3.962  -0.010 | 23-26 
 2005/6/23 |   | 20050420-31 | 20050618-3  3.959  -0.009 | 20050618-4  3.960  -0.010 | 18-22 
 2005/6/25 | 4 | 20050420-40 | 20050622-1  3.958  -0.007 | 20050622-2  3.960  -0.010 | 12-17 
 2005/6/26 |   | 20050420-39 | 20050622-1  3.957  -0.005 | 20050622-2  3.959  -0.010 | 5-11 
 2005/6/27 |   | 20050420-38 | 20050622-3  3.957  -0.009 | 20050622-4  3.961  -0.008 | 1-4 
____________________________________________________________________________________________________
 
 
(9) REAGENT BLANK THE BLANK DETERMINED IN THE SECTION 3.3.7, PURE WATER BLANK   
    (VBLK, DW) CAN BE REPRESENTED  BY EQUATION 1,

                    Vblk, dw = Vblk, ep + Vblk, reg                      (1).
 
where 

    Vblk, ep = blank due to differences between the measured end-point and the 
        equivalence point; 
    Vblk, reg = blank due to oxidants or reductants in the reagent. 
 
Here, the reagent blank (Vblk, reg) was determined by following procedure. 1 
cm3 of the standard potassium  iodate solution and 100 cm3 of deionized water 
were added to two flasks. 1 cm3 of sulfuric acid solution  and 0.5 cm3 of 
pickling reagent solution II and I each were added to the first flask in order. 
Then to the  second flask, two times volume of the reagents (2 cm3 of sulfuric 
acid solution, and 1.0 cm3 of pickling  reagent solution II and I each) was 
added. The reagent blank was determined by difference between the first  (2 cm3 
of the total reagent volume added) titrated volume of the sodium thiosulfate 
and the second (4 cm3  of the total reagent volume added) one. We also carried 
out experiments for three and four times volume of  the reagents. The results 
are shown in Figure 3.3.1. 
 
The relation between the reagent blank (Vblk, reg) and the volume of the 
reagents (Vreagent) is expressed  by equation 2, 

                    Vblk, reg = -0.0020 Vreagent + 0.0005                (2). 
 
There was no difference between the results of DOT-1 and DOT-2. Vblk, reg was 
estimated to be about -0.004  cm3, suggesting that about 0.02 µmol of 
reductants was contained in every 2 cm3 of the reagents added. In other words, 
the difference of the pure water blank (Vblk, dw) between DOT-1 and DOT-2, 
determined in the section 3.3.7, was due to the difference of the end-point 
blank (Vblk, ep) between the two titration apparatus (-0.003 and -0.006 cm3 for 
DOT-1 and DOT-2, respectively). 


(10) SAMPLE BLANK 

Blank due to redox species other than oxygen in the sample (Vblk, spl) can be a 
potential source of measurement error. Total blank during the seawater 
measurement, seawater blank (Vblk, sw) can be represented by equation 3, 

                    Vblk, sw = Vblk, spl + Vblk, ep + Vblk, reg          (3). 

If the end-point blank (Vblk, ep) is identical in pure water and in seawater, 
the difference between the seawater blank and the pure water one gives the 
sample blank (Vblk, spl), 

                    Vblk, sw - Vblk, dw = Vblk, spl                      (4). 

Vblk, spl was determined by following procedure. Seawater sample was collected 
in the volume calibrated glass flask (ca. 100 cm3) without the pickling. Then 1 
cm3 of the standard potassium iodate solution, 1 cm3 of sulfuric acid solution, 
and 0.5 cm3 of pickling reagent solution II and I each were added to the flask 
in order. Additionally, a flask contained 1 cm3 of the standard potassium 
iodate solution, 100 cm3 of deionized water, 1 cm3 of sulfuric acid solution, 
and 0.5 cm3 of pickling reagent solution II and I were prepared. The difference 
in the titrant volumes between the seawater flask and the deionized water one 
gave the sample blank (Vblk, spl). 

During this cruise we measured vertical profiles of the sample blanks at two 
stations (Table 3.3.2) using DOT-1 system. The sample blank ranged from 0.4 to 
0.9 µmol kg-1 and its vertical and horizontal variations are small. There are a 
few reports of the sample blank estimation of oxygen analysis in the open 
ocean. Our results agree with reported values ranged from 0.4 to 0.8 µmol kg-1 
(Culberson et al., 1991). Even if we ignore the sample blank which introduce 
systematic errors in the oxygen calculations, these errors are expected to be 
the same for all investigators and not to affect the comparison of results by 
different investigators (Culberson, 1994). 


Table 3.3.2. Results of the sample blank determinations during MR05-02. 
_______________________________________________________________________________

            Station: P10N-097                       Station: P10-019          
             30.5°N/149.3°E                           0.3°N/146.2°E 
 -------------------------------------   -------------------------------------
  Sample No.   CTD Pres.  Sample blank |  Sample No.   CTD Pres.  Sample blank 
 (Niskin No.)    dbar      µmol kg -1  | (Niskin No.)    dbar      µmol kg -1 
 -----------   --------   ------------ | -----------   --------   ------------
       5           51          0.5     |      35           51          0.4 
      33          151          0.6     |      33          150          0.7 
      31          249          0.6     |      31          251          0.7 
      29          402          0.7     |      29          401          0.9 
      27          602          0.6     |      27          601          0.7 
      25          800          0.6     |      25          801          0.7 
      23         1001          0.6     |      23         1001          0.7 
      21         1400          0.7     |      21         1400          0.7 
      17         2200          0.7     |      19         1802          0.7 
      15         2599          0.7     |      17         2200          0.7 
      13         3000          0.7     |      15         2600          0.7 
      11         3499          0.6     |      13         2999          0.7 
       9         4002          0.7     |      11         3499          0.7 
       7         4502          0.7     |       1         3770          0.9 
       5         4999          0.7     |                     
       3         5500          0.7     |                     
                 6251          0.7     |                     
 ______________________________________________________________________________


(11) REPLICATE SAMPLE MEASUREMENT  

Replicate samples were taken at every CTD cast. Total amount of the replicate 
sample pairs in good measurement (flag=2) was 452. The standard deviation of 
the replicate measurement was 0.11 µmol/kg and there was no significant 
difference between DOT-1 and DOT-2 measurements. The standard deviation was 
calculated by a procedure (SOP23) in DOE (1994). Figure 3.3.2 is plots of 
oxygen difference in the replicate measurement as a function of station 
sequential number and indicates the improvement of measurement skill during the 
cruise. There found large differences during the primary stage of the cruise. 
If we exclude the data at the initial ten stations from the calculation of 
standard deviation, it decreases to 0.09 µmol/kg. 

As is shown in Figure 3.3.3, the layers of replicate sampling are localized at 
the surface layer, 1200, 3000 and 5000 dbar depths. Since scattering of the 
plots somewhat depend on depths, we classified replicate data in the following 
categories: surface (<20 dbar), intermediate (500-1500 dbar) and deep (>1500 
dbar) layers. Standard deviation for each category is 0.16, 0.11, and 0.07 
µmol/kg, respectively. 


(12) DUPLICATE SAMPLE MEASUREMENT 

We also collected seawater samples from two Niskin samplers that were fired at 
same depth (duplicate sampling). Duplicate samples were taken at 49 stations in 
the deep layer below 2000 dbar, and 48 duplicate sample pairs were obtained 
successfully. From Figure 3.3.4, variation in measurement resolution is not 
clear during the period of this cruise. The standard deviation of the total 
duplicate measurement was about 0.11 µmol/kg. This value is roughly close to 
the standard deviation of the replicate measurement for the intermediate and 
deep layers (>500 dbar). Thus, we conclude that our measurement resolution of 
bottle oxygen is about 0.1 µmol/kg or less for MR05-02 cruise. 


(13) CSK STANDARD MEASUREMENTS 

The CSK standard solution is a commercial potassium iodate solution (0.0100 N) 
for analysis of oxygen in seawater. During this cruise, we measured 
concentration of the CSK standard solution (Lot ASE8280) against our KIO3 
standard in order to confirm accuracy of our oxygen measurement on board (Table 
3.3.3). Averaged values of DOT-1 and DOT-2 were 0.009999 ± 0.000002 N and 
0.009999 ± 0.000002 N respectively, which indicates that there was no 
systematic difference between DOT-1 and DOT-2 measurements. The averaged value 
of the CSK standard solution was so close to the certified value (0.0100 N) 
that we did not correct sample measurements with the CSK standard measurements. 
Additionally, we also measured another batch of the CSK standard solution, Lot 
TCK8677 that was also measured during our last cruise in 2003 (MR03-K04). We 
found that the measurements of the two batches of the CSK standard agreed well, 
suggesting that there was no systematic difference between our oxygen 
measurements in 2003 and in 2005. 


Table 3.3.3. Results of the CSK standard measurements. Table 3.3.4. Summary of 
             assigned quality control flags. 
     ______________________________________________________________________

                              |        DOT-1         |        DOT-2 
      Date (UTC)  KIO3 batch# | Conc. (N)  error (N) | Conc. (N)  error (N) 
      ---------   ----------- | --------   --------  | --------   --------
      2005/6/02   ASE8280-1   | 0.009997   0.000003  | 0.010002   0.000003 
      2005/6/11   ASE8280-2   | 0.010002   0.000003  | 0.009997   0.000003 
      2005/6/21   ASE8280-3   | 0.009999   0.000003  | 0.009997   0.000003 
      2005/6/27   ASE8280-4   | 0.009999   0.000005  | 0.009999   0.000003 
             Average          | 0.009999   0.000002  | 0.009999   0.000002 
                              |                      |
      2005/6/11   TCK8677     | 0.009999   0.000003  | 0.009997   0.000003 
     ______________________________________________________________________



                         Flag | Definition   
                         -----|--------------------------
                          2   | Good                 3294 
                          3   | Questionable            8 
                          4   | Bad                    14 
                          5   | Not report (missing)   14 
                          6   | Mean of replicate     452 
                              |              Total   3782 
                         

(14) QUALITY CONTROL FLAG ASSIGNMENT 

Quality flag values were assigned to oxygen measurements using the code defined 
in Table 0.2 of WHP Office Report WHPO 91-1 Rev.2 section 4.5.2 (Joyce et al., 
1994). Measurement flags of 2, 3, 4, 5 and 6 have been assigned (Table 3.3.4). 
For the choice between 2 (good), 3 (questionable) or 4 (bad), we basically 
followed a flagging procedure as listed below: 

 a. On a station-by-station basis, bottle oxygen and difference between bottle 
    oxygen and CTD oxygen at the time of rosette sampling were plotted against 
    CTD pressure. Any points not lying on a generally smooth trend were noted. 
 b. Dissolved oxygen was then plotted against potential temperature for several 
    stations. If a datum deviated from a group of plots, it was flagged 3 or 4. 
 c. If the bottle flag was 4 (Did not trip correctly), a datum was noted and 
    flagged 4, respectively. In case of the bottle flag 3 (Leaking), a datum 
    was flagged based on steps a. and b. 

Before the publishing of these data, as a post-cruise quality control for 
bottle oxygen, we carried out one more pass of flagging with the data at all 
stations. The following step was added. 

 d. In the oxygen-silicate diagram, data flagged 3 and 4 were examined once  
    more in the mass of all data. 

However, we found that all flaggings for 3 and 4 during the cruise were 
correct, therefore no data was upgraded to flag 2. Lastly, pairs of replicate 
both flagged 2 were averaged and flagged 6. 


REFERENCES 

Culberson, A.H. (1994): Dissolved oxygen, in WHPO Pub. 91-1 Rev. 1, November 
    1994, Woods Hole, Mass., USA. 
Culberson, A.H., G. Knapp, M.C. Stalcup, R.T. Williams, F. Zemlyak (1991): A 
    comparison of methods for the determination of dissolved oxygen in 
seawater, 
    WHPO Pub. 91-2, August 1991, Woods Hole, Mass., USA. 
Dickson, A. (1996): Determination of dissolved oxygen in sea water by Winkler 
    titration, in WHPO Pub. 91-1 Rev. 1, November 1994, Woods Hole, Mass., USA. 
DOE (1994): Handbook of methods for the analysis of the various parameters of 
    the carbon dioxide system in sea water; version 2. A.G. Dickson and C. 
Goyet 
    (eds), ORNL/CDIAC-74. 
Joyce, T., and C. Corry, eds., C. Corry, A. Dessier, A. Dickson, T. Joyce, M. 
    Kenny, R. Key, D. Legler, R. Millard, R. Onken, P. Saunders, M. Stalcup, 
    contrib. (1994): Requirements for WOCE Hydrographic Programme Data 
    Reporting, WHPO Pub. 90-1 Rev. 2, May 1994 Woods Hole, Mass., USA. 


3.4 NUTRIENTS 
    (2 July 2005)
 
(1) PERSONNEL 
    Michio Aoyama (Meteorological Research Institute/Japan Meteorological     
        Agency,Principal Investigator)
    Junko Hamanaka (Marine Works Japan Ltd.)
    Asako Kubo (Marine Works Japan Ltd.)
    Ayumi Takeuchi (Marine Works Japan Ltd.)


(2) OBJECTIVES 

The objectives of nutrients analyses during the R/V Mirai MR0502 cruise along 
149°E line in the Western North Pacific are as follows; Describe the present 
status of nutrients in good traceability. The target nutrients are nitrate, 
nitrite, phosphate and silicate (Although silicic acid is correct, we use 
silicate because a term of silicate is widely used in oceanographic community). 
Study temporal and spatial variations of nutrients based on the previous high 
quality experiments data of WOCE, GOESECS, IGY and so on. Study of temporal and 
spatial variation of nitrate: phosphate ratio, so-called Redfield ratio. Obtain 
more accurate estimation of total amount of nitrate, phosphate and silicate in 
the interested area. Provide more accurate nutrients data for physical 
oceanographers to use as tracers for water mass movement. 


(3) EQUIPMENT AND TECHNIQUES 

A. ANALYTICAL DETAIL USING TRAACS 800 SYSTEMS (BRAN+LUEBBE) 

The phosphate analysis is a modification of the procedure of Murphy and Riley 
(1962). 

Molybdic acid is added to seawater sample to form phosphomolybdic acid which is 
in turn reduced to phosphomolybdous acid using L-ascorbic acid as reductant. 

Nitrate + nitrite and nitrite are analyzed according to the modification method 
of Grasshoff (1970). 

The sample nitrate is reduced to nitrite in a cadmium tube inside of which is 
coated with metallic copper. The sample stream with its equivalent nitrite is 
treated with an acidic, sulfanilamide reagent and the nitrite forms nitrous 
acid which reacts with the sulfanilamide to produce a diazonium ion. N1-
Naphthylethylene-diamine added to the sample stream then couples with the 
diazonium ion to produce a red, azo dye. With reduction of the nitrate to 
nitrite, both nitrate and nitrite react and are measured; without reduction, 
only nitrite reacts. Thus, for the nitrite analysis, no reduction is performed 
and the alkaline buffer is not necessary. Nitrate is computed by difference. 

The silicate method is analogous to that described for phosphate. The method 
used is essentially the same as that of Grasshoff et al. (1983), where 
silicomolybdic acid is first formed from the silicic acid in the sample and 
added molybdic acid; then the silicomolybdic acid is reduced to silicomolybdous 
acid, or "molybdenum blue," using ascorbic acid as the reductant. 

The flow diagrams and regents for each parameter are shown in Figures 3.4.1-
3.4.4. 


NITRATE REAGENTS 

Imidazole (buffer), 0.06 M (0.4% w/v)
  Dissolve 4 g imidazole, C3H4N2, in ca. 900 ml DIW; add 2 ml concentrated HCl; 
  make up to 1000 ml with DIW. Aftermixing, 1 ml Triton(r)X-100 (50% solution 
  in ethanol) is added.
Sulfanilamide, 0.06 M (1% w/v) in 1.2M HCl
  Dissolve 10 g sulfanilamide, 4-NH2C6H4SO3H, in 1000 ml of 1.2 M (10%) HCl. 
  After mixing, 1ml Triton(r)X-100 (50% solution in ethanol) is added.
N-1-Napthylethylene-diamine dihydrochloride, 0.004 M (0.1% w/v)
  Dissolve 1 g NEDA, C10H7NHCH2CH2NH2_2HCl, in 1000 ml of DIW; containing 10 ml 
  concentrated HCl. Stored ina dark bottle.


NITRITE REAGENTS 

Sulfanilamide, 0.06 M (1% w/v) in 1.2 M HCl
  Dissolve 10 g sulfanilamide, 4-NH2C6H4SO3H, in 1000 ml of 1.2 M (10%) HCl. 
  After mixing, 1ml Triton(r)X-100 (50% solution in ethanol) is added.
N-1-Napthylethylene-diamine dihydrochloride, 0.004 M (0.1% w/v)
  Dissolve 1 g NEDA, C10H7NHCH2CH2NH2_2HCl, in 1000 ml of DIW; containing 10 ml 
  concentrated HCl. Stored ina dark bottle.


SILICIC ACID REAGENTS 

Molybdic acid, 0.06 M (2% w/v)
  Dissolve 15 g Disodium Molybdate(VI) Dihydrate, Na2MoO4_2H2O, in 1000 ml DIW 
  containing 6 ml H2SO4. Aftermixing, 20 ml sodium dodecyl sulphate (15% 
  solution in water) is added.
Oxalic acid, 0.6 M (5% w/v)
  Dissolve 50 g Oxalic Acid Anhydrous, HOOC: COOH, in 1000 ml of DIW.
Ascorbic acid, 0.01 M (3% w/v)
  Dissolve 2.5 g L (+)-Ascorbic Acid, C6H8O6, in 100 ml of DIW. Stored in a 
  dark bottle and freshly prepared beforeevery measurement.


PHOSPHATE REAGENTS 

Stock molybdate solution, 0.03 M (0.8% w/v)
  Dissolve 8 g Disodium Molybdate (VI) Dihydrate, Na2MoO4_2H2O, and 0.17 g 
  Antimony Potassium Tartrate,C8H4K2O12Sb2_3H2O, in 1000 ml of DIW containing 
  50 ml concentrated H2SO4.
Mixed Reagent
  Dissolve 0.8 g L (+)-Ascorbic Acid, C6H8O6, in 100 ml of stock molybdate 
  solution. After mixing, 2 ml sodiumdodecyl sulphate (15% solution in water) 
  is added. Stored in a dark bottle and freshly prepared before 
  everymeasurement. 
PO4 dilution
  Dissolve Sodium Hydrate, NaCl, 10 g in ca. 900 ml, add 50 ml Acetone and 4 ml 
  concentrated H2SO4, make up to1000 ml. After mixing, 5 ml sodium dodecyl 
  sulphate (15% solution in water) is added.


B. SAMPLING PROCEDURES 

Sampling of nutrients followed that of oxygen, trace gases and salinity. 
Samples were drawn into two of virgin 10 ml polyacrylates vials without sample 
drawing tubes. These were rinsed three times before filling and vials were 
capped immediately after the drawing. The vials are put into water a bath at 
26°C for 10 minutes before using to stabilize the temperature of samples. 

No transfer was made and the vials were set in an auto sampler tray directly. 
Samples were analyzed after collection, basically within 17 hours. 


C. DATA PROCESSING 

Raw data from TRAACS800 were treated as follows; 
Check baseline shift. 
Check the shape of each peak and positions of peak values taken, and then 
  change the positions of peak values taken, if necessary. 
Carryover correction and baseline drift correction were applied to peak 
  heights of each samples followed by sensitivity correction. 
Baseline correction and sensitivity correction were done, basically using
  liner regression. 
Load pressure and salinity from CTD data to calculate density of seawater. 
Calibration curves to get nutrients concentration were assumed second order 
  equations. 



(4) NUTRIENTS STANDARDS 
 
A. IN-HOUSE STANDARDS 

(I) VOLUMETRIC LABORATORY WARE 
 
All volumetric glass- and plastic (PMP)-ware used were gravimetrically 
calibrated. Plastic volumetric flasks were gravimetrically calibrated at the 
temperature of use within 2-3 K. 

Volumetric flasks 

Volumetric flasks of Class quality (Class A) are used because their nominal 
tolerances are 0.05% or less over the size ranges, which is likely to be used 
in this work. Class A flasks are made of borosilicate glass, and the standard 
solutions were transferred to plastic bottles as quickly as possible after they 
are made up to volume and well mixed in order to prevent excessive dissolution 
of silicic acid from the glass. High quality plastic (polymethylpentene, PMP, 
or polypropylene) volumetric flasks were gravimetrically calibrated and used 
only within 3-4 K of the calibration temperature. 

The computation of volume contained by glass flasks at various temperatures 
other than the calibration temperatures was done by using the coefficient of 
linear expansion of borosilicate crown glass. 

Because of their larger temperature coefficients of cubical expansion and lack 
of tables constructed for these materials, the plastic volumetric flasks were 
gravimetrically calibrated over the temperature range of intended use and used 
at the temperature of calibration within 3-4 K. The weights obtained in the 
calibration weightings were corrected for the density of water and air 
buoyancy. 

Pipettes and pipettors 

All pipettes have nominal calibration tolerances of 0.1% or better. These were 
gravimetrically calibrated in order to verify and improve upon this nominal 
tolerance. 


(II) REAGENTS, GENERAL CONSIDERATIONS GENERAL SPECIFICATIONS 

All reagents were of very high purity such as "Analytical Grade," "Analyzed 
Reagent Grade" and others. And assay of nitrite was determined according to 
JISK8019 and assays of nitrite salts were 98.9%. We use that value to adjust 
the weights taken. 

For the silicate standards solution, we use commercial available silicon 
standard solution for atomic absorption spectrometry of 1000 mg l-1. Since this 
solution is alkaline solution of 0.5 M KOH, an aliquot of 40 ml solution was 
diluted to 500 ml as B standard together with an aliquot of 20 ml of 1M HCl. 
Then the pH of B standard for silicate prepared to be 6.9. 

Ultra pure water 

Ultra pure water (MilliQ water) was used for preparation of reagents, higher 
concentration standards and for measurement of reagent and system blanks. 

Low-Nutrient Seawater (LNSW) 

Surface water with low nutrient concentration was taken and filtered using 0.45 
µm pore size membrane filter. This water is stored in 20 liter cubitainer with 
paper box. The concentrations of nutrient of this water were carefully measured 
in March 2005. 


(III) CONCENTRATIONS OF NUTRIENTS FOR A, B AND C STANDARDS 

Concentrations of nutrients for A, B and C standards are set as shown in Table 
3.4.1. The C standard is prepared according to the recipes as shown in Table 
3.4.2. All volumetric laboratory tools were calibrated prior the cruise as 
stated in chapter (i). Then the actual concentration of nutrients in each fresh 
standard was calculated based on the ambient, solution temperature and 
determined factors of volumetric laboratory wares. 


Table 3.4.1. Nominal concentrations of nutrients for A, B and C standards. 
             ______________________________________________________

                            A      B    C-1  C-2   C-3   C-4   C-5 
              ---------   -----   ----  ---  ---   ---   ---   --- 
              NO3  (µM)   45000    900   0     9    27    45    54  
              NO2  (µM)   4000      20   0   0.2   0.6   1.0   1.2 
              SiO2 (µM)   36000   2880   0    29    86   143   172 
              PO4  (µM)   3000      60   0   0.6   1.8   3.0   3.6 
             ______________________________________________________
             

Table 3.4.2. Working calibration standard recipes. 
                       __________________________________

                        C-STD   B-1 STD   B-2 STD   MAT 
                        -----   -------   -------  -----
                         C-2      5 ml      5 ml   50 ml 
                         C-3     15 ml     15 ml   30 ml 
                         C-4     25 ml     25 ml   10 ml 
                         C-5     30 ml     30 ml    0 ml 
                       __________________________________
                         B-1 STD: Mixture of nitrate, 
                                  silicate and phosphate 
                         B-2 STD: Nitrite 


(iv) Renewal of in-house standard solutions 

In-house standard solutions as stated in (iii) were renewed as shown in Table 
3.4.3. 


Table 3.4.3. Timing of renewal of in-house standards. 
   ________________________________________________________________________

    NO3, NO2, SiO2, PO4                       Renewal 
    ----------------------------------------  ----------------------------
    A-1 Std. (NO3)                            maximum 1 month 
    A-2 Std. (NO2)                            maximum 1 month 
    A-3 Std. (SiO2)                           commercial prepared solution 
    A-4 Std. (PO4)                            maximum 1 month 
    B-1 Std. (mixture of NO3, SiO2, PO4)      3 days 
    B-2 Std. (NO2)                            6 days 
    C Std                                     Renewal 
    ----------------------------------------  ----------------------------
    C-1 ~ C-5 Std (mixture of B1 and B2 Std.) 24 hours
    Reduction estimation                      Renewal 
    ----------------------------------------  ----------------------------
    D-1 Std.                                  when A-1renewed 
    43 µM NO3                                 when C-std renewed 
    47 µM NO2                                 when C-std renewed 
   ________________________________________________________________________



B. RMNS 

To get more accurate and high quality nutrients data for achieving the 
objectives stated above, huge numbers of the bottles of the reference material 
of nutrients in seawater (hereafter RMNS) are prepared (Aoyama et al., 
submitted). In the previous world wide expeditions, such as WOCE cruises, 
higher reproducibility and precision of nutrients measurements were required 
(Joyce and Corry, 1994). Since no standards were available for the measurement 
of nutrients in seawater at that time, the requirements were described in term 
of reproducibility. The required reproducibility was 1%, 1-2%, 1-3% for 
nitrate, phosphate and silicate, respectively. Although nutrient data from the 
WOCE one-time survey had unprecedented quality and coverage due to the 
uttermost care in sampling and measurements, the differences of nutrients 
concentration at crossover points are still found among the expeditions (Aoyama 
and Joyce, 1996, Mordy et al., 2000, Gouretski and Jancke, 2001). For instance, 
the mean offset of nitrate concentration at deep waters was 0.5 µmol kg-1 for 
345 crossovers at the world oceans, though the maximum was 1.7 µmol kg-1 
(Gouretski and Jancke, 2001). At the 31 crossover points in the Pacific WHP 
one-time lines, the WOCE standard of reproducibility for nitrate of 1% was 
fulfilled at about half of the crossover points and the maximum difference was 
7% at deeper layers below 1.6°C in potential temperature (Aoyama and Joyce, 
1996). 


(i) RMNS preparation RMNS preparation and homogeneity for previous lots 

The study on reference material for nutrients in seawater (RMNS) on the 
seawater base has been carried out to establish traceability on nutrient 
analyses in seawater since 1994, in Japan. Autoclaving to produce RMNS has been 
studied (Aminot and Kerouel, 1991, 1995) and autoclaving was used to stabilize 
the samples for the 5th intercomparison exercise in 1992/1993 (Aminot and 
Kirkwood, 1995). Aminot and Kerouel (1995) concluded that nitrate and nitrite 
were extremely stable throughout their 27 months storage experiment with 
overall standard deviations lower than 0.3% (range 5-50 µmol l-1) and 0.8% 
(range 0.5-5 µmol l-1), respectively. For phosphate, slight increase by 0.02-
0.07 µmol l-1 per year was observed due to leaching from the container glass. 
The main source of nutrient variation in seawater is believed to be 
microorganism activity, hence, production of RMNS depends on biological 
inactivation of samples. In this point of view, previous study showed that 
autoclaving to inactivate the biological activity is acceptable for RMNS 
preparation. 

In the R/V Mirai BEAGLE2003 cruise, which was round-the-world cruise along ca. 
30°S and conducted in 2003 and 2004, RMNS was analyzed at about 500 stations 
during the cruises. The results of BEAGLE2003 cruise will be available soon. 
(Databook of BEAGLE2003, 2005) 

The seawater for RMNS production was sampled in the North Pacific Ocean at the 
depths of the surface where the nutrients are almost depleted and at 1500-2000 
meters depth where the nutrients concentrations are the maximum. The seawater 
was gravity-filtered through a membrane filter with a pore size of 0.45 µm 
(Millipore HA). The latest procedure of autoclaving for RMNS preparation is 
that the seawater in a stainless steel container of 40 liters was autoclaved at 
120°C, for 2 hours, 2 times in two days. The filling procedure of autoclaved 
seawater was basically same throughout our study. Following cooling at room 
temperature in two days, polypropylene bottle of 100 ml capacity were filled by 
the autoclaved seawater of 90 ml through a membrane filter with a pore size of 
0.2 µm (Millipore HA) at a clean bench in a clean room. The polypropylene caps 
were immediately and tightly screwed on and a label containing lot number and 
serial number of the bottle was attached on all the bottles. Then the bottles 
were vacuum-sealed to avoid potential contamination from the environment. 

RMNSs for this cruise 

RMNS lots BC, AV, AX, AY and BA, which covers full range of nutrients 
concentrations in the western North Pacific are prepared as packages. These 
packages were renewed daily and analyzed every 2-6 runs on the same day. 150 
bottles of RMNS lot AZ are prepared to use every analysis at every hydrographic 
station. These RMNS assignment were completely done based on random number. The 
RMNS bottles were stored at a room, REGENT STORE, where the temperature was 
maintained at around 26-28°C. 


(ii) The homogeneity of RMNS and consensus values of the lot AH 

The homogeneity of lot BC and analytical precisions are shown in Table 3.4.4. 
These are for the assessment of the magnitude of homogeneity of the RMNS 
bottles that are used during the cruise. As shown in Table3.4.4, the 
homogeneity of RMNS lot BC for nitrate and silicate are the same magnitude of 
analytical precision derived from fresh raw seawater. The homogeneity for 
phosphate, however, exceeded the analytical precision at some extent. 


Table 3.4.4. Homogeneity of lot BC and previous lots derived from simultaneous 
             30 samples measurements and analytical precision onboard R/V Mirai 
             in May 2005. 
                     _________________________________________

                                 Nitrate   Phosphate  Silcate 
                                   CV%        CV%       CV% 
                      ---------  --------  ---------  -------
                      BC          0.22%      0.32%     0.19% 
                      (AH)       (0.39%)    (0.83%)   (0.13%) 
                      (K)        (0.3%)     (1.0%)    (0.2%)
                      Precision   0.22%      0.22%     0.12%
                     _________________________________________
                      Note: N = 30 x 2 


(5) QUALITY CONTROL 

A. PRECISION OF NUTRIENTS ANALYSES DURING THE CRUISE 

Precision of nutrients analyses during the cruise was evaluated based on the 12 
measurements, which were measured every 12 samples, during a run at the 
concentration of C-5. We also evaluated the reproducibility based on the 
replicate analyses of five samples in each run. Summary of precisions are shown 
in Table 3.4.5. As shown in Table 3.4.5 and Figures 3.4.5-3.4.7, the precisions 
for each parameter are generally good, considering the analytical precisions 
estimated from the simultaneous analyses of 60 samples in May 2005. Analytical 
precisions previously evaluated were 0.22% for phosphate, 0.22% for nitrate and 
0.12% for silicate, respectively. During this cruise, analytical precisions 
were 0.12% for phosphate, 0.09% for nitrate and 0.08% for silicate in terms of 
median of precision, respectively. Then we can conclude that the analytical 
precisions for phosphate, nitrate and silicate were maintained or better 
throughout this cruise, comparing the pre-cruise evaluations. The time series 
of precision are shown in Figures 3.4.5-3.4.7. 


Table 3.4.5. Summary of precision based on the replicate analyses of 12 samples 
             in each run through out cruise. 
                     _________________________________________

                                 Nitrate   Phosphate  Silcate 
                                   CV%        CV%       CV% 
                      ---------  --------  ---------  -------
                      Median      0.09       0.11      0.07 
                      Mean        0.09       0.12      0.08 
                      Maximum     0.17       0.29      0.19 
                      Minimum     0.03       0.05      0.03 
                      N           126        126       126 
                     _________________________________________


B. CARRY OVER 

We can also summarize the magnitudes of carryover throughout the cruise. These 
are as shown in Table 3.4.6. 


Table 3.4.6. Summary of carry over through out cruise. 
                     _________________________________________

                                 Nitrate   Phosphate  Silcate 
                                   CV%        CV%       CV% 
                      ---------  --------  ---------  -------
                      Median       0.30       0.24      0.21 
                      Mean         0.30       0.25      0.21 
                      Maximum      0.50       0.71      0.38 
                      Minimum      0.10       0.00      0.03 
                      N            126        126       126 
                     _________________________________________


(6) EVALUATION OF TRUENESS OF NUTRIENTS CONCENTRATIONS USING RMNSS 

We have been using RMNS for all runs, then, we can evaluate the trueness of 
nutrients concentration throughout the cruise. Results of RMNS measurements are 
shown in Figures 3.4.8-3.4.10. 

The uncertainties of nitrate, phosphate and silicate measurements for this 
cruise were evaluated as functions of concentrations of those. Uncertainties of 
nitrate measurement are expressed by eq. (1). 

               Uncertainties(%) = 0.13 + 1.66/Cnitrate          ••• (1)

where Cnitrate is nitrate concentration in µmol kg-1. 

Uncertainties of phosphate measurement are expressed eq. (2). 

               Uncertainties(%) = -0.11 + 1.032/Cphos           ••• (2)

where Cphos is phosphate concentration in µmol kg-1. 

Uncertainties of silicate measurement are expressed eq. (3). 

               Uncertainties(%) = 0.095 + 4.92/Csilicate        ••• (3)

where Csilicate is silicate concentration in µmol kg-1. 

Then, three columns to show the uncertainties of nutrients measurement were 
created in the sea file of this cruise. 


Table 3.4.7. Cruise to cruise tracerbility. 
              ____________________________________________________

                                          RM Lots 
               Cruise/Lab ---------------------------------------
                             AX      AV      BC      AZ      AH 

                                          NITRATE     
               BEAGLE2003                                   35.3 
               RY0501       21.8                    41.9    35.5 
               MR0501       21.5    33.4                    35.5 
               Pre-MR0502                   40.8      
               KANSO2005    21.4    33.2    40.5    41.9    35.9 
               MR0502       21.5    33.4    40.7    32.3      

                                          PHOSPHATE        
               BEAGLE2003                                   2.10 
               RY0501       1.52                    2.99    2.08 
               MR0501       1.62    2.52                    2.13 
               Pre-MR0502                   2.78      
               KANSO2005    1.59    2.48    2.72    3.01    2.03 
               MR0502       1.61    2.52    2.78    3.01   

                                          SILICATE     
               BEAGLE2003                                   133.8 
               RY0501       59.9                    135.6   133.8 
               MR0501       59.4    157.7                   135.5 
               Pre-MR0502                   160.7     
               KANSO2005    59.5    156.6   159.5   136.3   135.4 
               MR0502       59.5    157.9   159.9   137.1   
              ____________________________________________________


(7) CRUISE-TO-CRUISE TRACEABILITY 

Cruise-to-cruise traceability was examined based on the previous results of 
RMNSs obtained from several cruises and laboratory analyses. As shown in table 
3.4.7, the nutrients concentration of RMNSs was in good agreement among 
experiments. 


(8) PROBLEMS/IMPROVEMENTS OCCURRED AND SOLUTIONS 

As shown in Figure 3.4.7, the precisions of silicate concentration reached 
0.15-0.19% at several stations before station 118, where serial number of the 
station is 26. The cause of relatively higher precisions was attributed to be 
larger ambient temperature variability up to 1°C around 30 minutes interval. We 
re-arranged a setting of room temperature control to be more stable and 
obtained less room temperature variability around 0.5°C. Then we can see much 
better precision of silicate analyses after re-arrangement as shown in Figure 
3.4.7. 


REFERENCES 

Aminot, A. and Kerouel, R. 1991. Autoclaved seawater as a reference material 
    for the determination of nitrate and phosphate in seawater. Anal. Chim. 
    Acta, 248: 277-283. 

Aminot, A. and Kirkwood, D.S. 1995. Report on the results of the fifth ICES 
    intercomparison exercise for nutrients in sea water, ICES coop. Res. Rep. 
    Ser., 213. 

Aminot, A. and Kerouel, R. 1995. Reference material for nutrients in seawater: 
    stability of nitrate, nitrite, ammonia and phosphate in autoclaved samples. 
    Mar. Chem., 49: 221-232. 

Aoyama M., and Joyce T.M. 1996. WHP property comparisons from crossing lines in 
    North Pacific. In Abstracts, 1996 WOCE Pacific Workshop, Newport Beach, 
    California. 

Aoyama, M., Ota, H., Iwano, S., Kamiya, H., Kimura, M., Masuda, S., Nagai, N., 
    Saito, K., Tubota, H. 2004. 

Reference material for nutrients in seawater in a seawater matrix, Mar. Chem., 
    submitted. Grasshoff, K., Ehrhardt, M., Kremling K. et al. 1983. Methods of 
    seawater anylysis. 2nd rev. Weinheim: Verlag Chemie, Germany, West. 

JAMSTEC, BEAGLE2003 DATA BOOK (Volume 1 & 2), 2005. edited by H. Uchida and M. 
    Fukasawa, JAMSTEC 

Joyce, T. and Corry, C. 1994. Requirements for WOCE hydrographic programmed 
    data reporting. WHPO Publication, 90-1, Revision 2, WOCE Report No. 67/91. 

Kirkwood, D.S. 1992. Stability of solutions of nutrient salts during storage. 
    Mar. Chem., 38 : 151-164. 

Kirkwood, D.S. Aminot, A. and Perttila, M. 1991. Report on the results of the 
    ICES fourth intercomparison exercise for nutrients in sea water. ICES coop. 
    Res. Rep. Ser., 174. 

Mordy, C.W., Aoyama, M., Gordon, L.I., Johnson, G.C., Key, R.M., Ross, A.A., 
    Jennings, J.C. and Wilson. J. 2000. Deep water comparison studies of the 
    Pacific WOCE nutrient data set. Eos Trans-American Geophysical Union. 80 
    (supplement), OS43. 

Murphy, J., and Riley, J.P. 1962. Analytica chim. Acta 27, 31-36. 

Gouretski, V.V. and Jancke, K. 2001. Systematic errors as the cause for an 
    apparent deep water property variability: global analysis of the WOCE and 
    historical hydrographic data_REVIEW ARTICLE, Progress In Oceanography, 48: 
    Issue 4, 337-402. 



3.5 DISSOLVED INORGANIC CARBON (CT) 
    (31 August, 2006) 


(1) PERSONNEL 
    Akihiko Murata (IORGC/JAMSTEC)
    Mikio Kitada (MWJ)
    Yoshiko Ishikawa (MWJ)


(2) INTRODUCTION 

Concentrations of CO2 in the atmosphere are now increasing at a rate of 1.5 
ppmv y-1 due to human activities such as burning of fossil fuels, 
deforestation, cement production, and so on. It is an urgent task to estimate 
as accurately as possible the absorption capacity of the oceans against the 
increased atmospheric CO2, as well as to clarify the mechanism of CO2 
absorption, because the magnitude of predicted global warming depends on the 
levels of CO2 in the atmosphere, and the ocean currently absorbs 1/3 of the 6 
Gt of carbon emitted into the atmosphere each year by human activities. 

In this cruise (revisit of WOCE P10 line), we aimed to quantify how much 
anthropogenic CO2 is absorbed in North Pacific Intermediate Water, which is one 
of characteristic waters in the North Pacific. For the purpose, we measured 
CO2-system properties such as dissolved inorganic carbon (CT), total alkalinity 
(AT), pH and underway pCO2. 

In this section, we describe data on CT obtained in the cruise in detail. 


(2) APPARATUS 

Measurements of CT were made with two total CO2 measuring systems (systems A 
and B; Nippon ANS, Inc.), which are slightly different from each other. The 
systems comprise of a seawater dispensing system, a CO2 extraction system and a 
coulometer (Model 5012, UIC Inc.). 

The seawater dispensing system has an auto-sampler (6 ports), which takes 
seawater from a 300 ml borosilicate glass bottle and dispenses the seawater to 
a pipette of nominal 20 or 28 ml volume by a PC control. The pipette is kept at 
20°C by a water jacket, where water from a water bath set at 20°C is 
circulated. 

CO2 dissolved in a seawater sample is extracted in a stripping chamber of a CO2 
extraction system by adding phosphoric acid (10% v/v). The stripping chamber is 
approx. 25 cm long and has a fine frit at the bottom. To degas CO2 as quickly 
as possible, a heating wire kept at 40°C was rolled from the bottom to a 1/3 
height of the stripping chamber. The acid is added to the stripping chamber 
from the bottom of the chamber by pressurizing an acid bottle for a given time 
to push out a right amount of acid. The pressurizing is made with nitrogen gas 
(99.9999%). After the acid is transferred to the stripping chamber, a seawater 
sample kept in a pipette is introduced to the stripping chamber by the same 
method as in adding an acid. The seawater reacted with phosphoric acid is 
stripped of CO2 by bubbling the nitrogen gas through a fine frit at the bottom 
of the stripping chamber. The CO2 stripped in the stripping chamber is carried 
by the nitrogen gas (flow rates of 130 ml min-1 and 140 ml min-1 for the 
systems A and B, respectively) to the coulometer through a dehydrating module. 
For the system A, the module consists of two electric dehumidifiers (kept at 1 
- 2°C) and a chemical desiccant (Mg (ClO4)2). For the system B, it consists of 
three electric dehumidifiers with a chemical desiccant. 


(3) SHIPBOARD MEASUREMENT 

Sampling 

All seawater samples were collected from depth with 12 liter Niskin bottles 
basically at every other station. The seawater samples for CT were taken with a 
plastic drawing tube (PFA tubing connected to silicone rubber tubing) into a 
300 ml borosilicate glass bottle. The glass bottle was smoothly filled with 
seawater from the bottom following a rinse with seawater of 2 full, bottle 
volumes. The glass bottle was closed by a stopper, which was gravimetrically 
fitted to the bottle mouth without putting additional force. 

At a chemical laboratory on the ship, a headspace of approx. 1% of the bottle 
volume was made by removing seawater with a plastic pipette. A saturated 
mercuric chloride of 100 µl was added to poison seawater samples. The glass 
bottles were sealed with a greased (Apiezon M, M&I Materials Ltd.) ground glass 
stopper and the clips were secured. The seawater samples were kept at 4°C in a 
refrigerator until analysis. A few hours just before analysis, the seawater 
samples were kept at 20°C in a water bath. 

Analysis 

At the start of each leg, we calibrated the measuring systems by blank and 5 
kinds of Na2CO3 solutions (nominally 500, 1000 1500, 2000, 2500 µmol/l). As it 
was empirically known that coulometers do not show a stable signal (low 
repeatability) with fresh (low absorption of carbon) coulometer solutions. 
Therefore we measured 2% CO2 gas repeatedly until the measurements became 
stable. Then we started the calibration. 

The measurement sequence such as system blank (phosphoric acid blank), 2% CO2 
gas in a nitrogen base, seawater samples (6) was programmed to repeat. The 
measurement of 2% CO2 gas was made to monitor response of coulometer solutions 
(from UIC, Inc.). For every renewal of coulometer solutions, certified 
reference materials (CRM, batch 69) provided by Prof. A. G. Dickson of Scripps 
Institution of Oceanography were analyzed. In addition, reference materials 
(RM) provided by JAMSTEC (2 kinds) and KANSO were measured at the initial, 
intermediate and end times of a coulometer solution's lifetime. 

The preliminary values were reported in a data sheet on the ship. Repeatability 
and vertical profiles of CT based on raw data for each station helped us check 
performances of the measuring systems. 

In the cruise, we finished all the analyses for CT on board the ship. As we 
used two systems, we had not encountered such a situation that we had to 
abandon the measurement due to time limitation. However, we experienced some 
malfunctions of the measuring systems during the cruise, which are described in 
the followings: 

There occurred lowering of repeatability, mostly due to dirt. This situation 
was recovered by cleaning the measuring systems. For the system B, we could not 
recover good repeatability (~1.5 µmol kg-1). To obtain good repeatability, we 
changed the pipette of a volume of 20 ml to that of a volume of 28 ml; 

The "undershooting" of coulometer detection was often found. This happened in 
measuring seawater samples subsequent to the measurement of phosphoric acid 
blank. To avoid the "undershooting" occurred in seawater sample measurement, we 
measured a dummy seawater sample subsequent to the bank measurement. 


(4) Quality control 

Calibration factors of the systems A and B were listed in Table 3.5.1. With 
these factors, we calculated CT of CRM (batch 69), and plotted the values as a 
function of sequential day (Fig. 3.5.1). From Fig. 3.5.1, it is found that 
there were no trends of CRM measurements for both the systems. The averages and 
standard deviations were 1906.7 and 0.7 µmol kg-1 (n = 36), respectively, for 
the system A and 1907.2 and 1.1 µmol kg-1 (n = 28), respectively for the system 
B. Since the certified value of the batch 69 is 1907.63 µmol kg-1, very close 
to the averages, it implies that the measurements had been conducted in a good 
condition during the cruise. 

Based on the results of CRM measurements stated above, we re-calculated the 
calibration factors so that measurements of seawater samples become traceable 
to the certified value of batch 69. 

Temporal variations of RM measurements are shown in Fig. 3.5.2. From Fig. 
3.5.2, it is evident that RM measurements had a linear trend, implying that 
measurements of seawater samples also have the trend. The trend was also found 
in temporal changes of 2% CO2 gas measurements. The trend seems to be due to 
"cell age" change (Johnson et al., 1998) of a coulometer solution. 

Considering the trends, we adjusted measurements of seawater samples to be 
traceable to the certified value of batch 69, although the adjustments were 
usually slight. 

Finally we surveyed vertical profiles of CT. In particular, we examined whether 
systematic differences between measurements of the systems A and B existed or 
not. Then taking other information of analyses into account, we determined a 
flag of each value of CT. 

The average and standard deviation of absolute values of differences of CT 
analyzed consecutively were 1.2 and 1.1 µmol kg-1 (n = 209), respectively. 


REFERENCE 

Johnson, K.M., A.G. Dickson, G. Eischeid, C. Goyet, P. Guenther, R.M. Key, F. 
    J. Millero, D. Purkerson, C.L. Sabine, R.G. Schottle, D.W.R. Wallace, R.J. 
    Wilke and C.D. Winn (1998): Coulometric total carbon dioxide analysis for 
    marine studies: assessment of the quality of total inorganic carbon 
    measurements made during the US Indian Ocean CO2 survey 1994-1996, Mar. 
    Chem., 63, 21-37. 


Table 3.5.1. Calibration factors determined from Na2CO3 solutions. 
_____________________________________________________________________________

 Cruise Name.  Calibration factors   Remarks 
 ------------  -------------------   ---------------------------------------
                  A           B       
 MR05-02       0.24479     0.25114   A pipette for the system B was replaced 
                           0.31326       
_____________________________________________________________________________



3.6 TOTAL ALKALINITY (AT) 
    (10 October, 2006)

 
(1) PERSONNEL 
    Akihiko Murata (IORGC/ JAMSTEC)
    Fuyuki Shibata (MWJ)
    Taeko Ohama (MWJ)


(2) INTRODUCTION 

Concentrations of CO2 in the atmosphere are now increasing at a rate of 1.5 
ppmv y-1 due to human activities such as burning of fossil fuels, 
deforestation, cement production, and so on. It is an urgent task to estimate 
as accurately as possible the absorption capacity of the oceans against the 
increased atmospheric CO2, as well as to clarify the mechanism of the CO2 
absorption, because the magnitude of predicted global warming depends on the 
levels of CO2 in the atmosphere, and the ocean currently absorbs 1/3 of the 6 
Gt of carbon emitted into the atmosphere each year by human activities. 

In this cruise (revisit of WOCE P10 line), we aimed to quantify how much 
anthropogenic CO2 is absorbed in North Pacific Intermediate Water, which is one 
of the characteristic waters in the North Pacific. For the purpose, we measured 
CO2-system properties such as dissolved inorganic carbon (CT), total alkalinity 
(AT), pH and underway pCO2. 

In this section, we describe data on AT obtained in the cruise in detail. 


(2) APPARATUS 

The measuring system for AT (customized by Nippon ANS, Inc.) comprises of a 
water dispensing unit, an auto-burette (Metrohm), a pH meter (Thermo Orion) and 
auto-sampler (6 ports). They are automatically controlled by a PC. Separate 
electrodes (Reference electrode: REF201, (Radiometer), Glass pH electrode: 
pHG201-7 (Radiometer)), or combined electrodes (ROSS 8102BN, Thermo Orion) were 
used. 

A seawater of approx. 40 ml is transferred from a sample bottle (borosilicate 
glass bottle; 130 ml) into a water-jacketed (25°C) by pressurized N2 gas, and 
is introduced into a water-jacketed (25°C) titration cell. Next, a given volume 
of titrant is injected into the titration cell. By this, pH of a seawater 
sample becomes 4.5-4.0. The seawater sample mixed with the titrant is stirred 
for three minutes by a stirring chip. Then a small volume of titrant (~0.1 ml) 
is injected until pH or e.m.f. reaches a given value. The concentration of the 
acid titrant is nominally 0.05 M HCl in 

0.65 M NaCl. Calculation of AT is made based on a modified Gran approach. 


(3) SHIPBOARD MEASUREMENT 

Sampling 

All seawater samples were collected from depth using 12 liter Niskin bottles 
basically at every other stations. The seawater samples for AT were taken with 
a plastic drawing tube (PFA tubing connected to silicone rubber tubing) into 
borosilicate glass bottles of 130 ml. The glass bottle was filled with seawater 
smoothly from the bottom after rinsing it with seawater of a half a or a full 
bottle volume. A few hours before analysis, the seawater samples were kept at 
25°C in a water bath. 


Analysis 

For AT measurement, we selected electrodes, which showed signals close to 
theoretical Nernstian behavior. 

At the start of each leg, we conducted calibration of the acid titrant, which 
was prepared on land. The calibration was made by measuring AT of 5 solutions 
of Na2CO3 in 0.7 M NaCl solutions. The computed ATs were approx. 0, 100, 1000, 
2000 and 2500 µmol kg-1. The measured values of AT (calculated by assuming 0.05 
M acid titrant) should be a linear function of the AT contributed by the 
Na2CO3. The linear function was fitted by the method of least squares. 
Theoretically, the slope of the linear function should be unity. If the 
measured slope is not equal to unity, the acid normality should be adjusted by 
dividing initial normality by the slope, and the whole set of calculations is 
repeated until the slope = 1. 

Before starting analyses of seawater samples, we measured AT of dummy seawater 
samples to confirm a condition of the measuring system. If repeat measurements 
of AT were constant within ~3 µmol kg-1, we initiated measurement of seawater 
samples. We analyzed reference materials (RM), which were produced for CT 
measurement by JAMSTEC, but were efficient also for the monitor of AT 
measurement. In addition, certified reference materials (CRM, batch 69, 
certified value = 2114.42 µmol kg-1) were also analyzed periodically to monitor 
systematic differences of measured AT. The reported values of AT were set to be 
traceable to the certified value. 

The preliminary values were reported in a data sheet on the ship. Repeatability 
calculated from replicate samples and vertical profiles of AT based on raw data 
for each station helped us check performance of the measuring system. 

In the cruise, we finished all the analyses for AT on board the ship. We did 
not encounter such serious problems that we had to give up the analyses. 
However, we experienced some malfunctions of the system during the cruise, 
which are listed in the followings: 

After analyses of a large number of samples, we often experienced a drift of an 
electrode, which appeared as differences of pH or e.m.f. against a constant 
volume of titrant injected into a seawater sample. In this case, we changed pH 
or e.m.f. ranges for the subsequent calculation of AT. 


(4) QUALITY CONTROL 

We examined vertical profiles of AT. Then, taking other information of analyses 
into account, we determined a flag of each value of AT. 

The average and standard deviation of absolute values of differences of AT 
analyzed consecutively were 1.8 and 1.6 µmol kg-1 (n = 207), respectively. 
 


3.7 pH 
    (12 October, 2006) 


(1) PERSONNEL 
    Akihiko Murata (IORGC, JAMSTEC)
    Fuyuki Shibata (MWJ)
    Taeko Ohama (MWJ)


(2) INTRODUCTION 

Concentrations of CO2 in the atmosphere are now increasing at a rate of 1.5 
ppmv y-1 due to human activities such as burning of fossil fuels, 
deforestation, cement production, and so on. It is an urgent task to estimate 
as accurately as possible the absorption capacity of the oceans against the 
increased atmospheric CO2, as well as to clarify the mechanism of the CO2 
absorption, because the magnitude of anticipated global warming depends on the 
levels of CO2 in the atmosphere, and the ocean currently absorbs 1/3 of the 6 
Gt of carbon emitted into the atmosphere each year by human activities. 

In this cruise (revisit of WOCE P10 line), we aimed to quantify how much 
anthropogenic CO2 absorbed in North Pacific Intermediate Water, which is one of 
the characteristic waters in the North Pacific. For the purpose, we measured 
CO2-system properties such as dissolved inorganic carbon (CT), total alkalinity 
(AT), pH and underway pCO2. 

In this section, we describe data on pH obtained in the cruise in detail. 


(3) APPARATUS 

Measurement of pH was made by a pH measuring system (Nippon ANS, Inc.), which 
adopts spectrophotometry. The system comprises of a water dispensing unit and a 
spectrophotometer (Carry 50 Scan, Varian). 

Seawater is transferred from borosilicate glass bottle (300 ml) to a sample 
cell in the spectrophotometer. The length and the volume of the cell are 8 cm 
and 13 ml, respectively, and the sample cell was kept at 25.00 ± 0.05°C in a 
thermostated compartment. First, absorbances of seawater only are measured at 
three wavelengths (730, 578 and 434 nm). Then an indicator is injected and 
circulated for about 4 minutes to mix the indicator and seawater sufficiently. 
After the pump is stopped, the absorbance of seawater + indicator are measured 
at the same wavelengths. 

The pH is calculated based on the following equation (Clayton and Byrne, 1993): 

                                  A1/A2 - 0.00691 
                pH = pK2 + log ---------------------- ,            (1)
                               2.2220 - 0.1331(A1/A2) 

where A1 and A2 indicate absorbance at 578 and 434 nm, respectively, and pK2 is 
calculated as a function of water temperature and salinity. 


(3) SHIPBOARD MEASUREMENT 

Sampling 

All seawater samples were collected from depth with 12 liter Niskin bottles 
basically at every other station. The seawater samples for pH were taken with a 
plastic drawing tube (PFA tubing connected to silicone rubber tubing) into a 
300 ml borosilicate glass bottle, which was the same as used for CT sampling. 
The glass bottle was filled with seawater smoothly from the bottom following a 
rinse with a sea water of 2 full, bottle volumes. The glass bottle was closed 
with a stopper, which was gravimetrically fitted to the bottle mouth without 
additional force. 

A few hours before analysis, the seawater samples were kept at 25°C in a water 
bath. 

Analysis 

For an indicator solution, m-cresol purple (2 mM) was used. The indicator 
solution was produced on board a ship, and retained in a 1000 ml DURAN(r) 
laboratory bottle. We renewed an indicator solution 3 times when the headspace 
of the bottle became large, and monitored pH or absorbance ratio of the 
indicator solution by another spectrophotometer (Carry 50 Scan, Varian) using a 
cell with a short path length of 0.5 mm. In most indicator solutions, the 
absorbance ratios of the indicator solution were initially in the range 1.4 -
1.6, and decreased to 1.1. 

It is difficult to mix seawater with an indicator solution sufficiently under 
no headspace condition. However, by circulating the mixed solution with a 
peristaltic pump, a well-mixed condition came to be attained rather shortly, 
leading to a rapid stabilization of absorbance. We renewed a TYGON(r) tube of a 
peristaltic pump periodically, when a tube deteriorated. 

Absorbances of seawater alone and seawater + indicator solutions were measured 
15 times each, and averages computed from the last five values of absorbance 
were used for the calculation of pH (Eq. 1). 

The preliminary values of pH were reported in a data sheet on the ship. 
Repeatability calculated from replicate samples and vertical profiles of pH 
based on raw data for each station helped us check performance of the measuring 
system. 

We finished all the analyses for pH on board the ship. We did not encounter 
such a serious problem that we had to give up the analyses. However, we 
sometimes experienced malfunctions of the system during the cruise: 

Differences between absorbances of seawater alone and those of seawater + 
indicator solution were infrequently greater than ± 0.001. This implies dirt of 
the cell. In this case, we cleaned or replaced the cell. 


(4) QUALITY CONTROL 

It is recommended that correction for pH change resulting from addition of 
indicator solutions is made (DOE, 1994). To check perturbation of pH due to the 
addition, we measured absorbance ratios by doubling the volume of indicator 
solutions added to a same seawater sample. We corrected absorbance ratios based 
on an empirical method (DOE, 1994). Figure 3.7.1 illustrates an example of 
perturbation of absorbance ratios by adding indicator solutions. 

We surveyed vertical profiles of pH. In particular, we examined whether 
systematic differences between before and after the renewal of indicator 
solutions existed or not. Then taking other information of analyses into 
account, we determined a flag of each value of pH. 

The average and standard deviation of absolute values of differences of pH 
analyzed consecutively were 0.0006 and 0.0006 pH unit (n = 203), respectively. 


REFERENCES 

Clayton, T.D. and R.H. Byrne (1993): Spectrophotometric seawater pH 
    measurements: total hydrogen ionconcentration scale calibration of m-cresol 
    purple and at-sea results. Deep-Sea Research 40, 2115-2129.

DOE (1994): Handbook of methods for the analysis of the various parameters of 
    the carbon dioxide system in sea water, version 2, A. G. Dickson & C. 
    Goyet, eds. (unpublished manuscript). 



3.8 CHLOROFLUOROCARBONS (CFCs) 
    (2 October 2006) 


(1) PERSONNEL 
    Ken'ichi SASAKI (MIO, JAMSTEC)
    Masahide WAKITA (MIO, JAMSTEC)
    Hideki YAMAMOTO (MWJ)
    Katsunori SAGISHIMA (MWJ)
    Yuichi SONOYAMA (MWJ)


(2) INTRODUCTION 

Chlorofluorocarbons (CFCs) are completely man-made gasses that are chemically 
and biologically stable gasses in the environment. The CFCs have accumulated in 
the atmosphere since 1930s (Walker et al., 2000) and the atmospheric CFCs can 
slightly dissolve in sea surface water. The dissolved CFCs concentrations in 
sea surface water should have changed year by year and then penetrate into the 
ocean interior by water circulation. Three chemical species of CFCs, namely 
CFC-11 (CCl3F), CFC-12 (CCl2F2) and CFC-113 (C2Cl3F3), dissolved in seawater 
are useful transient tracers for the ocean circulation with times scale on the 
order of decades. In this cruise, we determined concentrations of these CFCs in 
seawater on board. 


(3) APPARATUS 

Dissolved CFCs were measured by a typical method modified from the original 
design of Bullister and Weiss (1988). Two systems were used for CFCs 
measurement. A custom made purging and trapping system was attached to gas 
chromatograph (GC-14B: Shimadzu Ltd) having an electron capture detector (ECD-
14: Shimadzu Ltd). Stainless steel tube packed Porapak T(r) was used as a cold 
trap. Silica Plot capillary column [i.d.: 0.53 mm, length: 4 m, tick:  0.25 µm] 
and a complex capillary column (Pola Bond-Q [i.d.: 0.53 mm, length: 7 m, tick: 
6.0 µm] followed by Silica Plot [i. d.: 0.53 mm, length: 22 m, tick: 0.25 µm]) 
was used as a pre-column and main column, respectively. 


(4) SHIPBOARD MEASUREMENT 

Sampling 

Before casting CTD, the water sampling system was cleaned by diluted acetone to 
remove any oils which could cause contaminations of CFCs. Seawater sub-samples 
for CFCs measurement were collected from 12 liter Niskin bottles into 300ml 
glass bottle. The bottle had been filled with pure nitrogen gas before the sub-
sampling. The two times bottle volumes of seawater sample were overflowed. The 
bottles filled with seawater were kept in water bathes roughly controlled on 
the sample temperature. The CFCs concentrations were determined as soon as 
possible. 

Analysis 

Constant volume of sample water (50ml) was taken into the purging & trapping 
system. Dissolved CFCs were de-gassed by nitrogen gas purge and concentrated in 
a trap column cooled to -40°C. The CFCs were desorbed by electrically heating 
the trap column to 140°C within 1.5 minutes, and led into the pre-column. CFCs 
and other compounds were roughly separated in the pre-column and the compounds 
having earlier retention time than CFCs were sent to main analytical column. 
And then the pre-column was flushed buck by counter flow of pure nitrogen gas 
(Back flush system). The back flush system prevented any compounds that had 
higher retention time than CFCs from entering main analytical column and 
allowed short time analysis. CFCs which were sent into main column were 
separated further and detected by an electron capture detector (ECD). Retention 
time of each CFC was around 1.5, 

4.2 and 10.5 minutes for CFC-12, CFC-11 and CFC-113, respectively. Temperatures 
of an analytical column and a detector were 95 and 240°C, respectively. Pure 
nitrogen gas (99.9999) was purified by a molecular sieve 13X gas purifier and 
was used for CFCs analysis. Mass flow rates of nitrogen gas were 21, 16, 20 and 
200 ml/min for carrier, detector make up, back flush and sample purging gasses, 
respectively. 

Gas loops whose volumes were around 1, 3 and 10 ml were used for introducing 
standard gases into the analytical system. The standard gasses had been made by 
Japan Fine Products co. ltd. Cylinder numbers of CPB30524 and CPB30525 of 
standard gasses were used for reference gas and running gas, respectively. 
These gasses contained roughly 300, 160 and 30 ppt (v/v) of CFC-11, CFC-12 and 
CFC-113, respectively (nitrogen base). Precise mixing ratios of the standard 
gasses were calculated by gravimetric data. The standard gases used in this 
cruise have not been calibrated to SIO scale standard gases yet because SIO 
scale standard gasses is hard to obtain due to legal difficulties for CFCs 
import into Japan. The data will be corrected as soon as possible when we 
obtain the standard gasses. 


(4) QUALITY CONTROL 

Blank 

Some blank water samples which were made by nitrogen purge of seawater in CFCs 
sample bottle were analyzed and any CFCs were not detected. Significant 
increase in CFCs concentration during keeping sampling bottle in a water bath 
was not found for around one week. CFCs concentrations in deep water which was 
one of the oldest water masses in the ocean were low but not zero for CFC-11 
and -12. Average concentrations of CFC-11, 12 in denser water than 27.5 sigma-0 
were 0.022 ± 0.011, 0.004 ± 0.004 (n = 449). These values were assumed as 
sampling blanks which was contaminations from Niskin bottle and/or during sub-
sampling and were subtracted from all data. 

Interfering compound for CFC-113 analysis 

A large and broad peak was interfered determining CFC-113 peak area for samples 
collected from surface 200 m depth in the latitude band between 33°N and 8°N,. 
Retention time of the interfering peak was around 3% shorter than that of CFC-
113. The peak of a compound interfering CFC-113 determination could not be 
completely separated from the peak of CFC-113 by our analytical condition. We 
tried to split these peaks on chromatogram analysis and give flag "4". In the 
case of the interfering peak completely covering the CFC-113 peak, we could not 
determine CFC-113 peak area and give flag "5". 

Precisions 

The analytical precisions were estimated from replicate sample analyses. The 
replicate samples were basically collected from two sampling depths which is 
around 250 m and 800 m depth. Because lateral and vertical variations of CFC 
concentrations were very large, CFC data were divided into two groups for the 
estimation based on concentration ranges, i.e. high concentration group which 
was more than 1.0 pmol kg-1 of CFC-11 and -12 and 0.1 pmol kg-1 of CFC-113 and 
low concentration group which was below the above concentrations. The 
precisions were estimated by two methods. One (A) is estimated by following 
equation, s= (∑ (∆C2)/(2n-1))0.5, where ∆C is difference between replicate 
analyses (Table 1). Another (B) is average difference of replicate analyses 
(with standard deviation, SD) (Table 2). 


Table 1. Analytical precisions of CFC concentrations estimated from method (A). 
         __________________________________________________________________

                    Conc. Range    Mean (SD)     Precisions     
          CFCs      (pmol kg-1)   (pmol kg-1)    (pmol kg-1)   Data number
          -------   -----------   -----------    -----------   -----------
          CFC-11       Whole      1.33 (1.13)       0.008          219 
                       ≥ 1.0      2.17 (0.80)       0.009          121 
                       < 1.0      0.29 (0.29)       0.005           98 
          CFC-12       Whole      0.71 (0.61)       0.006          219 
                       ≥ 1.0      1.46 (0.33)       0.008           69 
                       < 1.0      0.36 (0.34)       0.005          150 
          CFC-113      Whole      0.08 (0.09)       0.005          155 
                       ≥ 0.1      0.20 (0.08)       0.007           43 
                       < 0.1      0.04 (0.02)       0.000          112 
         __________________________________________________________________


Table 2. Analytical precisions of CFC concentrations estimated from method (B). 
         __________________________________________________________________

                    Conc. Range    Mean (SD)      Precisions    
          CFCs      (pmol kg-1)   (pmol kg-1)    (pmol kg-1)   Data number
          -------   -----------   -----------    -----------   -----------
          CFC-11       Whole      1.33 (1.13)   0.007 (0.008)      219 
                       ≥ 1.0      2.17 (0.80)   0.010 (0.009)      121 
                       < 1.0      0.29 (0.29)   0.004 (0.005)      98 
          CFC-12       Whole      0.71 (0.61)   0.006 (0.006)      219 
                       ≥ 1.0      1.46 (0.33)   0.008 (0.007)      69 
                       < 1.0      0.36 (0.34)   0.004 (0.005)      150 
          CFC-113      Whole      0.08 (0.09)   0.005 (0.005)      155 
                       ≥ 0.1      0.20 (0.08)   0.007 (0.006)      43 
                       < 0.1      0.04 (0.02)   0.004 (0.005)      112 
         __________________________________________________________________
 
 
REFERENCES 

Walker, S.J., Weiss, R.F. and Salameh, P.K., Reconstructed histories of the 
    annual mean atmospheric mole fractions for the halocarbons CFC-11, CFC-12, 
    CFC-113 and Carbon Tetrachloride, Journal of Geophysical Research, 105, 
    14,285-14,296, (2000). 

Bullister, J.L and Weiss, R.F. Determination of CCl3F and CCl2F2 in seawater 
    and air. Deep Sea Research, 35, 839-853 (1988). 



3.9 LOWERED ACOUSTIC DOPPLER CURRENT PROFILER 
    (25 August 2006) 


(1) PERSONNEL 
    Shinya Kouketsu (JAMSTEC)
    Yasushi Yoshikawa (JAMSTEC)


(2) INSTRUMENT AND MEASUREMENT 

Direct flow measurement from sea surface to the bottom was carried out using a 
lowered acoustic Doppler current profiler (LADCP). The instrument used was the 
RDI Workhorse Monitor 307.2 kHz unit (RD Instruments, USA). The instrument was 
attached on the CTD/RMS frame, orientating downward. The CPU firmware version 
was 16.05. The firmware was updated at station P10-002 to version 16.27. 

One ping raw data were recorded. Settings for the collecting data are listed in 
Table 3.9.1. A total of 128 operations were made with the CTD observations. The 
performance of the LADCP instrument was good in northern stations (in the 
subarctic region of North Pacific). Profiles were obtained over 100 m distance 
from LADCP in shallow depth and almost 60 m in deeper depth. On the other hand, 
the performance was bad in southern stations in the subtropical region of North 
Pacific. In the deeper depth, good quality data were obtained only 3 or 4 bins, 
which means the LADCP could observe only about 25 m. It would due to a weak 
echo intensity, which agreed with ship's ADCP. Data transfer errors were often 
occurred during upload process from the LADCP to PC. 


(3) DATA PROCESS AND RESULT 

Vertical profiles of velocity are obtained by the inversion method (Visbeck, 
2002). Both the up and down casts are used for the inversion. Since the first 
bin from LADCP is influenced by the turbulence generated by CTD frame, the 
weight for the inversion is set to small value of 0.1. The GPS navigation data 
are used in the calculation of the reference velocities and the bottom-track 
data are used for the correction of the reference velocities. Shipboard ADCP 
(SADCP) data averaged for 3 minites are also included in the calculation. The 
CTD data are used for the sound speed and depth calculation. IGRF 
(International Geomagnetic Reference Field) 10th generation data are used for 
calculating magnetic deviation to correct the direction of velocity. In the 
processing, we use Matlab routines provided from M. Visbeck and G. Krahmann 
(http://ladcp.ldeo.columbia.edu/ladcp/). 


Table 3.9.1. LADCP Settings for the collecting data. 
_________________________________________________________________________________

 Station      143-50,48,47   49      46        45         44,X04        42-
 Bin length       8 m        8 m     12 m      12 m        12 m         16 m 
 Bin number       24         20      16        20          16           10 
 Standard dev.  2 cm/s     2 cm/s   1.6 cm/s  1.6 cm/s    1.6 cm/s    1.4 cm/s  
 Ping interval  1.2 sec    1 sec    1.2 sec   1.2 sec     1.2 sec      1 sec 
 Percent Good   Collect    Collect  Collect   Collect   Not collect  Not collect 
_________________________________________________________________________________


Figure 3.9.1 and 3.9.2 show the results of the cross-section velocity (eastward 
is positive) and the along-section velocity (northward is positive). The major 
currents in the Western Pacific such as the Kuroshio Extension (P10N-116-114), 
the Equatorial Under Current (around P10-18), and New Guinea Coastal Under 
Current (P10-002) appeared in the figures. Figure 3.9.3 shows error velocity 
estimated by the inversion method. The error velocities are very small (less 
than 5 cm/s) upper 1000 dbar and adjacent to the bottom. Since the absolute 
velocities are obtained only by LADCP data from bottom track, the error 
velocity near the bottom is small. Upper 1000 dbar, the error velocity is small 
due to SADCP data. The velocity profile obtained from LADCP without SADCP 
resembles the one from SADCP. The uncertainty of velocity from SADCP is about 
10 cm/s. So we think the error velocity from LADCP upper 1000 dbar is about 10 
cm/s. The error velocities are less than 10 cm/s on the northern side of the 
Kuroshio Extension. However, error velocities are large in the subtropical 
gyre. It is probably due to the short range of the LADCP signal, which makes 
the shears suspicious. In the estimation of the velocity from LADCP data, it is 
the biggest problem that there is less information of the CTD frame motion, 
which is only determined from bottom track data and GPS data. 


REFERENCE 

Visbeck, M. (2002): Deep velocity profiling using Lowered Acoustic Doppler 
    Current Profilers: Bottom track and inverse solutions. J. Atmos. Oceanic 
    Technol., 19, 794-807. 




FIGURE CAPTIONS 

Figure  1: Station locations for WHP P10 revisit cruise with bottom topography 
           based on Smith and Sandwell (1997). 

Figure  2: Bathymetry measured by Multi Narrow Beam Echo Sounding system. Cross 
           mark indicates CTD location. 

Figure  3: Surface wind measured at 25 m above sea level. Wind data is averaged 
           over 1-hour and plotted every 0.5 degree in latitude. 

Figure  4: Sea surface temperature (SST) and salinity (SSS). Temperature and 
           salinity  data are averaged over 1hour.

Figure 5: Difference in the partial pressure of CO2 between the ocean and the 
           atmosphere, ∆pCO2. 

Figure  6: Surface current at 100 m depth measured by shipboard acoustic 
           Doppler current profiler (ADCP). 

Figure  7: Potential temperature (°C) cross section calculated by using CTD 
           temperature and salinity data calibrated by bottle salinity 
           measurements. Vertical exaggeration of the 0-6,500 m section is 
           1000:1. Expanded section of the upper 1000 m is made with a vertical 
           exaggeration of 2500:1. 

Figure  8: CTD salinity (psu) cross section calibrated by bottle salinity 
           measurements. Vertical exaggeration is same as Figure 7. 

Figure  9: Same as Figure 8 but with SSW batch correction(1). 

Figure 10: Density (σ0) (kg/m3) cross section calculated using CTD temperature 
           and calibrated salinity data with SSW batch correction. Vertical 
           exaggeration is same as Figure 7. 

Figure 11: Same as Figure 10 but for σ4 (kg/m3). 

Figure 12: Neutral density (yn) (kg/m3) cross section calculated using CTD 
           temperature and calibrated salinity data with SSW batch correction. 
           Vertical exaggeration is same as Figure 7. 

Figure 13: Cross section of bottle sampled dissolved oxygen (µmol/kg). Data 
           with quality flags of 2 were plotted. Vertical exaggeration is same 
           as Figure 7. 

Figure 14: Silicate (µmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 15: Nitrate (µmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration of the upper 1000 m section is same 
           as Figure 7. 

Figure 16: Nitrite (µmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 17: Phosphate (µmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 18: Dissolved inorganic carbon (µmol/kg) cross section. Data with 
           quality flags of 2 were plotted. Vertical exaggeration is same as 
           Figure 7. 

Figure 19: Total alkalinity (µmol/kg) cross section. Data with quality flags of 
           2 were plotted. Vertical exaggeration is same as Figure 7. 

Figure 20: pH cross section. Data with quality flags of 2 were plotted. 
           Vertical exaggeration is same as Figure 7. 

Figure 21: CFC-11 (pmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 22: CFC-12 (pmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 23  CFC-113 (pmol/kg) cross section. Data with quality flags of 2 were 
           plotted. Vertical exaggeration is same as Figure 7. 

Figure 24  Cross section of current velocity (cm/s) normal to the cruise track 
           measured by LADCP (eastward is positive). 

Figure 25: Difference in potential temperature (°C) between results from WOCE 
           (from Oct. to Nov., 1993) and the revisit cruise (from May to Jul., 
           2005). Red and blue areas show the areas where potential temperature 
           increased and decreased in revisit cruise, respectively. On white 
           areas differences in temperature do not exceed the detection limit 
           of 0.002°C. Vertical exaggeration is same as Figure 7. 

Figure 26: Difference in salinity (psu) between results from WOCE and the 
           revisit cruise. Red and blue areas show the areas where salinity 
           increased and decreased in the revisit cruise, respectively. CTD 
           salinity data with SSW batch correction1 are used. On white areas 
           differences in salinity do not exceed the detection limit of 0.002 
           psu. Vertical exaggeration is same as Figure 7. 

Figure 27: Difference in dissolved oxygen (µmol/kg) between results from WOCE 
           and Revisit. Red and blue areas show the areas where salinity 
           increased and decreased in the revisit cruise, respectively. CTD 
           oxygen data are used. On white areas differences in salinity do not 
           exceed the detection limit of 2 µmol/kg. Vertical exaggeration is 
           same as Figure 7. 

Note 1. As for the traceability of SSW to Mantyla's value, the offset for the 
        batches P114 (WOCE P10), and P145 (Revisit) is +0.0007 and -0.0013, 
        respectively (Kawano et al., 2006). 


REFERENCES 

Jackett, D. R. and R. J. McDougall (1997): A neutral density variable for the 
    world's oceans, Journal of Physical Oceanography, 27, 237-263. 

Smith, W. H. F. and D. T. Sandwell (1997): Global seafloor topography from 
    satellite altimetry and ship depth soundings, Science, 277, 1956-1962. 

Kawano, T., M. Aoyama, T. M. Joyce, H. Uchida, Y. Takatsuki and M. Fukasawa 
    (2006): The Latest Batch-to-batch Difference Table of Standard Seawater and 
    Its Application to the WOCE Onetime Sections, Journal of Oceanography, 62 
    (6), 777-792.
