
preliminary data report
may 19, 1995
A.	Cruise Narrative

A.1	Highlights

A.1.a	WOCE designation	PR18
A.1.b	EXOCODE			49TU9207_1
A.1.c	Chief Scientist		Eiichi Moriyama, NMO
A.1.d	Ship			R/V Chofu Maru
A.1.e	Port of Call		None
A.1.f	Cruise Dates		July 24 to July 31, 1992

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. Principal Investigators for All Measurements
-----------------------------------------------------
       Name           Responsibility      Affiliation
-----------------------------------------------------
      T. Tomiyama      CTD,S                 NMO
      M. Aoyama        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 NC9207 Leg 1. The ship sailed from Nagasaki at
0600 UTC on 24 July 1992.  By 0358 UTC on 27 July. the ship was at
the first station of a section PR18. The cruise track and station
locations are shown in Figure 1. The observations of PR18 finished
at 0938 UTC on 29 July.  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
A.6	Other Incidents of Note
A.7	List of Cruise Participants

		Table 2. Cruise Participants
---------------------------------------------------------------
       Name           Responsibility      Affiliation
---------------------------------------------------------------
      E. Moriyama      Chief Scientist,       NMO
                       CTD Hardware
      T. Tomiyama      CTD,S                  NMO
      T. Hinata        CTD Software           NMO
      T. Shiga         S,CTD Hardware         NMO
      N. Nagai         Watch Stander          NMO
      T. Shimizu       O2,Nutrients           NMO
      T. Kobuchi       Watch Stander          NMO
      S. Saito         Watch Stander          NMO
      H. Nakane        Maritime Meteorology   NMO
----------------------------------------------------------------      

B.	Underway Measurements

B.1	Navigation and bathymetry
B.2	Acoustic Doppler Current Profiler (ADCP)
B.3	Thermosakinograph 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.

     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 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 first we fixed the joint of sea cable, but this problem was not
settled. Eventually this ploblem was caused by slippage between the
stepping motor and the tripping mechanism. After leg one, we
exchanged parts for the tripping mechanism and adjusted it in Naha.
And then we exchanged Rosette Commander, too. Therefore this
problem was settled.  


     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 sixth 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 temperature
and pressure are shown in Table 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 16 Jan. 1992     -0.0061256   0.9998243
 
          Pressure increasing (0-1600 dbar range); linear fit

             Time             Bias        Slope

Pre -Cruise 15 Jan. 1992     -0.469709    0.9993401
Post-Cruise 28 Sep. 1992     -0.175173    0.9992790
-----------------------------------------------------------------

     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 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
0.0005 PSS derived from the standard deviation of the eighteen
water samples collected from the same bottle.
     About the tempreture scale, we used the ITS-90 scale.


Table 4. The conductivity scaling factor
--------------------------------------------
Station No.         Bias      Slope
PN-1 - PN-9           -       0.99983
--------------------------------------------          
 
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             30
Average                  204.2     umol/l
One sigma                  0.84    umol/l
precision                  0.4     %
-----------------------------------------------------------
                                                      

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-6,PN-5,PN-4',PN-4,PN-3
and PN-1.  

     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.

---------------------------------------------------
     unit:%
     Nitrate        Nitrite        Phosphate
---------------------------------------------------
      1.53           1.24            1.78
   (0.53-2.49)    (0.49-16.67)    (1.05-7.82)       
---------------------------------------------------    

     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      27.2      PN-8      27.2      PN-7      27.2
PN-6      26.8      PN-5      26.8      PN-4'     27.0
PN-4      27.0      PN-3'     27.4      PN-3      28.6
PN-2      26.7      PN-1      26.3                    
--------------------------------------------------------
                                                     

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;

     NC9207R.SUM
     NC9207R1.SEA 


5.1 --.SUM

     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. 

     Bottle quality flag "4" is double-tripping of the water
sampling bottles.

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

                                                      

6. GPS
     For examine the accuracy of the position data of the GPS
systems, standard deviation were caluculated 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
-----------------------------------------------------
August 5  Naha           34.3m          19.9m
-----------------------------------------------------                   

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)

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.  
