Preliminary data report
may 19, 1995
A. 	Cruise Narrative

A.1	Highlights 

A.1.a	WOCE Designation 	PR18 
A.1.b	EXPOCODE		49TU9110/1 (PR18)
				

A.1.c	Chief Scientist		Eiichi Moriyama, NMO
A.1.d	Ship			R/V Chofu Maru

A.1.e	Ports of Call		Leg 1 Nagasaki to Naze
				

A.1.f	Cruise Date		October 16 to October 29, 1991
 				


A.2	Cruise Summary
A.2.a	Geographic boundaries
A.2.b	Total number of stations occupied
A.2.c	Floats and drifters deployed
A.2.d	Moorings deployed or recovered

A.3	List of Principal Investigators

 Table 1: 	List of Principal Investigators

	Table 1. Principal Investigators for All Measurements

          Name               Responsibility          Affiliation
      ----------------------------------------------------------	
      Yoshisuke Tomiyama     CTD,S                     NMO
      Michio Aoyama          O2, Nutrients             NMO
      Nobuaki Shikama	     Mooring		       MRI 
      Keizou Sakurai         Maritime Meteorology      NMO
      ----------------------------------------------------------

A.4	Scientific Programme and Methods

Observation of PR19 were carried out on the R/V Chofu Maru Cruise
NC9110.  The ship sailed from Nagasaki at 0600 UTC on 16 October 1991
and finished the observation PR18.  By 2140 UTC on 23 October the ship
was at the first station of section PR19.

The observation was cut at the station IS-6a and course was set for
Amami Is. to avoid the typhoon "T9123".  After we let it go past, the
ship called at Naze and Ishigaki.  The ship sailed for the ADCP mooring
at east Taiwan at 0500 UTC on 5 November.  The ADCP mooring was
deployed on 6 November, then the ship sailed for NS-1.  However, the
observation was stopped at the station NS-6 to avoid the coming typhoon
"T9124" again.  The observation of PR19 ended at 1800 UTC on 7 November.

Water sampling on the cruise included measurements of salinity both by
CTD and water bottle samples, CTD temperature, bottle sample oxygen
determination, and nutrients (nitrate, nitrite, and phosphate).

During the cruise CTD stations were occupied using a 12 bottle rosette
equipped with 1.7 liter Niskin water sampling bottles.

A.5	Major Problems and Goals not achieved
A.6	Other incidents of Note
A.7	List of Cruise Participants

       Name               Responsibility              Affiliation
      ------------------------------------------------------------   
      Eiichi Moriyame     Chief Scientist              NMO 
      S. Michio Aoyama    O2,Nutrients                 NMO
      Tomoaki Hinata      CTD Hardware,                NMO
                          CTD Software
      Hitomi Kamiya       Watch Stander                NMO
      Junichi Jifuku      O2,Nutrients                 NMO
      Toshihiro Ishihara  Watch Stander                NMO
      Takao Shimizu       O2,Nutrients                 NMO
      Shoji Shiraishi     CTD Software                 NMO
      Keizou Sakurai      Maritime Meteorology         NMO
      -----------------------------------------------------------

B.	Underway Measurements

B.1	Navigation and Bathymetry
B.2	Acoustic Doppler Current Profiler (ADCP)
B.3	Thermosalinograph and underway dissolved oxygen, fluorometer, etc
B.4	XBT and XCTD
B.5	Meteorological observations
B.6	Atmospheric chemistry

C.	Hydrographic Measurements

CTD Measurements

The EG&G NBIS Mark III B CTD (6500 dbar sensor, without
oxygen sensor) mounted in the 12 x 1.7 liter General Oceanics
rosette multisampler frame was used for all of the vertical CTD
work. In general at the CTD stations of which depth are shallower
than 100 meters and than 4000 meters, the package was lowered to
within 5 meters of the bottom and lowered to the depth of 95
percents of the bottom depth, respectively, because unable to use
the acoustic pinger on DSF-6000 fathometer.
     
The performance of the CTD and multisampler was good throughout
the cruise.

A Hewlett Packard HP9000-320 with a 2 MByte of memory was
used as a primary data collection device and all CTD data was
backed up onto the audio tape. The original sampling rate is
31.25 samples per second, however, our software can get around 20
samples per second and compress it one tenth of the collected
data due to the limitation of the memory. All of the CTD data of
our observatory was loaded on the basis of the compressed data
described above.

The results of the laboratory calibration for the tempera-
ture and pressure are shown in Tables 3, however, these were not
used because the calibration methods for temperature and pressure
are not decided.

Table 3. CTD calibration constants at laboratory
----------------------------------------------------------------
           Temperature; linear fit
                   Time          Bias         Slope

Pre -Cruise       12 Mar.1991    0.0067286    0.9998651
Post-Cruise       13 Jan.1992    0.0090696    0.9996329

           Pressure Increasing (0-6000 dbar range); linear fit
                   Time          Bias         Slope

Pre -Cruise       11 Oct.1991    3.9799       1.000511
Post-Cruise       13 Jan.1992    2.5492       1.000661
----------------------------------------------------------------

The conductivity scaling factor given in Table 4 is derived
from not a linear fit but a ratio of CTD data to water sample
data and were used for the final data load. The salinity determi-
nation of the water sample with the Guildline PORTASAL 8410.
Standard Seawater batch of P114 was used to standardize the
PORTASAL. The precisions of the salinity determination were
0.0006 PSS for 16 water samples from the same bottle.

Table 4. The conductivity scaling factor
----------------------------------------------
Station No.             Bias            Slope
PN-1  - PN-9              -            0.99977
----------------------------------------------

                                              
Oxygen measurements

The determination of dissolved oxygen was done by the
modified version of the Winkler method described in "Kaiyou
kansoku shishin (Manual of Oceanographic Observation)" published
by the Oceanographical Society of Japan (1970). The reagent blank
was not subtracted. The results of the estimation of precision
are shown in Table 5. No estimation of accuracy has been made.

Table 5. The precision of the oxygen analyses by three analyst
--------------------------------------------------------------
                      Experiment A      Experiment B
Sample Number              17               21   
Average               214.41 umol/l     222.56 umol/l
One sigma               0.25 umol/l       0.46 umol/l
precision               0.11 %            0.21 %
--------------------------------------------------------------

Nutrient analyses

The nutrients analyses were done by the Technicon Auto
Analyzer II described in "Kaiyou kansoku shishin (Manual of
Oceanographic Observation)" published by the Oceanographical
Society of Japan (1970). 

Sampling for nutrients followed that for dissolved oxygen on
average 10-20 minutes after the casts were on deck. Samples were
drawn into 10 cm3 glass, narrow mouth, screw-capped bottles. Then
they were immediately introduced on the sampler tray of the
Technicon Auto Analyzer II for the analysis and generally the
analyses were begun within one hour after the casts were on deck.
if the delays were anticipated to be more than one hour, the
samples were refrigerated. Samples were refrigerated and stored
up to one hour on stations PN-3, PN-6 and PN-8.  

The precisions of the onboard Nitrate and Nitrite analyses
estimated from the standard deviation of the five samples from
the same working standard solution on each analysis are shown in
Table 5. The precision of the onboard Phosphate analysis estimat-
ed from the standard deviation of the four samples from the same
working standard solutions are also shown in Table 6. The concen-
trations of the working standard of nitrate, nitrite and phos-
phate were 40 umol/l, 2 umol/l and 3 umol/l, respectively. No
estimation of accuracy have been made.


Table 6. The median and the range ( in the parentheses) of the
precision of the onboard nutrients analyses throughout PR18 and
PR19.
-------------------------------------------------
     unit:%
     Nitrate        Nitrite        Phosphate

      1.20           0.40            1.20
   (0.10-5.00)    (0.06-2.80)    (0.40-2.50)       
-------------------------------------------------    

The concentrations in umol/kg of oxygen, nitrate, nitrite
and phosphate were converted from the concentrations in umol/l
using the density calculated from the room temperature and salin-
ity of the water samples. The laboratory temperature for each
station are given in Table 7.

Table 7. Laboratory temperature for each station.
--------------------------------------------------------
Station   Temp.     Station   Temp.     Station   Temp.
PN- 1     22.       PN- 2     24.       PN- 3     25.
PN- 3'    24.       PN- 4     24.       PN- 4'    26.
PN- 5     28.       PN- 6     28.       PN- 7     28.
PN- 8     28.       PN- 9     28.
--------------------------------------------------------                                                        


Notes for the --.SUM,--.SEA and --.CTD files

The first 2 characters of the file name of --.SUM, --.SEA
and --.CTD files  are NC for R/V Chofu Maru of Nagasaki Marine
Observatory. These characters are followed by the last two digits
of year, the month and character R (R for PR18) or character S (S
for PR19) for the --.SUM and --.SEA files. In addition, the leg
of the cruise is appended in the file name of --.SEA files. For
the --.CTD files The characters NC are followed by the unique
station number and the cast number given in the Comments.

The file names of the --.SUM and --.SEA for this cruise are
as follows;

     NC9110R.SUM, 
     NC9110R1.SEA 

--.SUM

Since some of the time at the bottom (BO) and completion
(EN) of the cast, the positions at the beginning (BE), bottom
(BO) and the completion (EN) of the cast and the water depth of
station were not recorded, we leave the column of them blank. 

Since the surface water samplings were by a stainless steel 
water bucket, "Number of bottles" includes this bucket sampling.
  
The unique station numbers given by the Japan Meteorological
Agency with the cast numbers, which are used as the --.CTD files
name, are given in the "Comments".


--.SEA

We leave "the sample number (SAMPNO)" blank because the
sample numbers are different among the salinity, oxygen and
nutrients on our assignments.  

Since the surface water samplings were by a stainless steel 
water bucket, we leave the column of  "The Bottle Number
(BTLNBR)" at the surface layer blank. 

All water sample quality flags for the oxygen during this
cruise were "3" because the precision did not exceed the WOCE
standard of 0.1% and no estimation of accuracy has been made.


--.CTD

The number of samples averaged at the pressure level, NUM-
BER, was the estimated value because original CTD data were lost
in the processing described in "Section 2. CTD".


D.	Acknowledgements
E.	References

Oceanographical Society of Japan, 1970. Kaiyou kansoku shishin
(Manual of Oceanographic Observation). Ed. by the Japan Meteoro-
logical Agency. (in Japanese)


Unesco, 1983. International Oceanographic tables. Unesco Technical Papers in 
Marine Science, No. 44.

Unesco, 1991. Processing of Oceanographic Station Data, 1991. By JPOTS
editorial panel.

F.	WHPO Summary

Several data files are associated with this report.  They are the TU91101.sum, 
TU91101.hyd, TU91101.csl and *.wct files.  The TU91101.sum file contains a 
summary of the location, time, type of parameters sampled, and other pertient
information regarding each hydrographic station.  The TU91101.hyd file contains
the bottle data. The *.wct files are the ctd data for each station.  The *.wct 
files are zipped into one file called TU91101wct.zip. The TU91101.csl file is 
a listing of ctd and calculated values at standard levels.

The following is a description of how the standard levels and
calculated values were derived for the TU91101.csl file:

Salinity, Temperature and Pressure:  These three values were smoothed from
the individual CTD files over the N uniformly increasing pressure levels.
using the following binomial filter-

	t(j) = 0.25ti(j-1) + 0.5ti(j) + 0.25ti(j+1) j=2....N-1

When a pressure level is represented in the *.csl file that is not
contained within the ctd values, the value was linearly interpolated
to the desired level after applying the binomial filtering.   

Sigma-theta(SIG-TH:KG/M3), Sigma-2 (SIG-2: KG/M3), and Sigma-4(SIG-4:
KG/M3): These values are calculated using the practical salinity scale
(PSS-78) and the international equation of state for seawater (EOS-80)
as described in the Unesco publication 44 at reference pressures of the
surface for SIG-TH; 2000 dbars for Sigma-2; and 4000 dbars for Sigma-4.

Gradient Potential Temperature (GRD-PT: C/DB 10-3) is calculated as the
least squares slope between two levels, where the standard level is the
center of the interval.  The interval being the smallest of the two
differences between the standard level and the two closest values.
The slope is first determined using CTD temperature and then the
adiabatic lapse rate is subtracted to obtain the gradient potential
temperature.  Equations and Fortran routines are described in Unesco
publication 44.

Gradient Salinity (GRD-S: 1/DB 10-3) is calculated as the least squares
slope between two levels, where the standard level is the center of the
standard level and the two closes values.  Equations and Fortran
routines are described in Unesco publication 44.

Potential Vorticity (POT-V: 1/ms 10-11) is calculated as the vertical
component ignoring contributions due to relative vorticity, i.e.
pv=fN2/g, where f is the coriolius parameter, N is the bouyancy
frequency (data expressed as radius/sec), and g is the local
acceleration of gravity. 

Bouyancy Frequency (B-V: cph) is calculated using the adiabatic
leveling method, Fofonoff (1985) and Millard, Owens and Fofonoff
(1990).  Equations and Fortran routines are described in Unesco
publication 44.

Potential Energy (PE: J/M2: 10-5) and Dynamic Height (DYN-HT: M) are
calculated by integrating from 0 to the level of interest.  Equations and 
Fortran routines are described in Unesco publication, Processing of 
Oceanographic station data.

Neutral Density (GAMMA-N: KG/M3) is calculated with the program GAMMA-N
(Jackett and McDougall) version 1.3 Nov. 94.  


G.	Data Quality Evulation                                                                           


