preliminary data report
may 19, 1995
A.	Cruise Narrative

A.1	Highlights

A.1.a	WOCE Designation	PR18
A.1.b	EXPOCODE		49TU9210/1
A.1.c	Chief Scientist         Yoshisuke Tomiyama, NMO
A.1.d	Ship                    R/V Chofu Maru
A.1.e	Port of Call            Nagasaki to Nagasaki
A.1.f	Cruise Dates            October 5 to October 17, 1992

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

A.3	List of Principal Investigators


Table 1. Principal Investigators for All Measurements
-----------------------------------------------------
       Name           Responsibility      Affiliation
-----------------------------------------------------
      T. Tomiyama      CTD,S                 NMO
      K. Kimura        O2,Nutrients          NMO
-----------------------------------------------------
  
A.4	Scientific Programme and Methods

Observations of PR18 were carried out as a part of the R/V
Chofu Maru Cruise NC9210 Leg 1. The ship sailed from Nagasaki at
0600 UTC on 5 October 1992.  By 1738 UTC on 8 October, the ship was
at the first station of a section PR18. 

At the station PN-d', the Raytheon acoustic fathometer system
broke down.  After this incident, the bottom depths were the
estimated value from the navigation chart or a bottom depth which
is observed in the last time cruise.

The observations of PR18 finished at 1711 UTC on 10 October. 
Water sampling on the cruise included mesurements of salinity both
by CTD and water bottle samples, CTD temperature, bottle sample
oxygen determination, and nutrients (nitrates, nitrites, and
phosphates).  

A.5	Major Problems and Goals not Achieved

None Reported

A.6	Other incidents of Note

A.7	List of Cruise Participants

    


		Table 2. Cruise Participants
--------------------------------------------------------------
       Name           Responsibility      Affiliation
--------------------------------------------------------------
      Y. Tomiyama      Chief Scientist,       NMO
                       CTD,S,O2
      E. Moriyama      CTD Hardware           NMO
      T. Tashiro       Watch Stander          NMO
      T. Shiga         S                      NMO
      T. Shimizu       O2,Nutrients           NMO
      J. Jifuku        O2,Nutrients           NMO
      S. Saito         CTD Software           NMO
      S. Shiraishi     CTD Software           NMO
      H. Fukushima     Maritime Meteorology   NMO
-------------------------------------------------------------

B.	Underway Measurements
B.1	Navigation and bathymetry
B.2	Acoustic Doppler and 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


The NBIS Mark III B CTD (1600 dbar sensor without oxygen
sensor) mounted on the 12 x 1.7 Liter General Oceanics rosette
multisampler frame was used for all of the vertical CTD work.

The performance of the CTD was good throughout the cruise, but
the multisampler was no good in leg one, because there were some
mis-firings and double-tripping of the water sampling bottles. So,
the rossete commander unit replaced by sub one, but this problem
was not settled. Eventually this problem was caused by slippage
between the stepping motor and the tripping mechanism. The CTD re-
cast were carried out at the station of PN-8 and PN-7 for double
tripping. At the station of PN-6, one of the Niskin bottles was
broken, therefore, that repleced by another one.   

The CTD full sampling was started from this cruise. The
details of the data collection and data processing methods are
described in "CTD Full Sampling and Data Processing Method Used at
Nagasaki Marine Observatory". These methods were based on Millard
and Yang ( 1992 ). 

The results of the laboratory calibration for the temperature
and pressure are shown in Table 3. These calibration constants were
used from this cruise. 


Table 3. CTD calibration constants at laboratory
---------------------------------------------------------------
          Temperature; linear fit
             Time             Bias        Slope
Pre -Cruise 26 Sep. 1992      0.0042191   0.9999142
 
          Pressure increasing (0-1600 dbar range); linear fit
             Time             Bias        Slope
Pre -Cruise 28 Sep. 1992     -0.175173    0.9992790

          Pressure decreasing (0-1600 dbar range); linear fit
             Time             Bias        Slope
Pre -Cruise 28 Sep. 1992     -1.4067743   0.9999869
---------------------------------------------------------------

The conductivity scaling factor given in Table 4 is derived
from a linear fit of CTD data to water sample data and were used
for the final data load. The salinity determination of the water
samples was with the Guildline AUTOSAL 8400A. Standard Seawarter
batch of P114 was used to standardize the AUTOSAL. The precision of
the salinity determination of the water samples was 0.0003 PSS
derived from the standard deviation of the fifteen water samples
collected from the same bottle.


Table 4. The conductivity scaling factor; linear fit
----------------------------------------------------
Station No.         Bias           Slope
PN-1 - PN-9         0.008894       0.999761
----------------------------------------------------

A temperature time lag was decided using the CTD time constant
dicision program, time lag was 0.288 seconds. The ITS-90 scale was
used for the temperature and potential temperature scale.

3. 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 oxygen analises by three analysts
------------------------------------------------------------
          Sample Number  Average   One sigma      precision
                         umol/l    umol/l         %

Analyst A      10        210.6     0.36           0.18
Analyst B       9        210.7     0.18           0.09
Analyst C      10        209.7     0.28           0.13
------------------------------------------------------------
                                                      

4. 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-9,PN-8,PN-7,PN-5,PN-4' and PN-3.  

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
6. The precision of the onboard Phosphate analysis estimated from
the standard deviation of the four samples from the same working
standard solutions are also shown in Table 5. The concentrations of
the working standard of nitrate, nitrite and phosphate 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.
--------------------------------------------------------------
       Nitrate          Nitrite          Phosphate     unit:%
--------------------------------------------------------------
        0.287            1.457            0.824
    (0.040-2.875)    (0.063-10.560)   (0.106-2.947)       
--------------------------------------------------------------    

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 salinity 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-9      26.8      PN-8      26.8      PN-7      29.5
PN-6      29.5      PN-5      24.8      PN-4'     27.8
PN-4      27.8      PN-3'     25.8      PN-3      26.2
PN-2      24.8      PN-1      24.                    
-----------------------------------------------------------
                                                
5. 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;

     NC9210R.SUM, 
     NC9210R1.SEA 


5.1 --.SUM

Since some of the water depth of the cast 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".


5.2 --.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.


5.3 --.CTD

     The files name were given in the Comments of --.SUM files.


6. GPS

For examine the accuracy of the position data of the GPS
systems, standard deviations were caluculated in after cruise. The
position data were good throughout the cruise. The results are
shown in Table 8.


Table 8. Standard deviation of position data
-------------------------------------------------
Date      Port           Standard deviation
                         Latitude       Longitude
Oct. 22   Nagasaki       19.6m          26.4m
--------------------------------------------------
                                             
 
D.	Acknowledgments
E.	References

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

Aoyama,M, S.Saito, T.Kobuchi and S.Shiraishi, 1993: CTD full
Sampling and Data Processing Method Used at Nagasaki Marine
Observatory. (Draft)

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 tu92071.sum, 
tu92071.hyd, tu92071.csl and *.wct files.  The tu92071.sum file contains a 
summary of the location, time, type of parameters sampled, and other pertient
information regarding each hydrographic station.  The tu92071.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 tu92071.wct.zip. The tu92071.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 tu92071.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