R/V Ryofu Maru Cruise RY9401

1. Cruise Narrative

1.1 Highlights

Expedition Designation(EXPOCODE): 49RY9401/1

Chief Scientist:        Katsuhiko Fushimi,
                        Japan Meteorological Agency,
                        1-3-4, Otemachi, Chiyoda-ku,
                        Tokyo 100, Japan

Ship:     R/V Ryofu Maru

Ports of Call:
          Leg 1: Tokyo, Japan to Naha, Japan

Cruise Dates:
          Leg 1: January 18, 1994 to February 7, 1994

1.2 Cruise Summary

Cruise Track
          The cruise track and station locations are shown in
Figure 1. Observations of PR02 were carried out as part of the R/V
Ryofu Maru cruise RY9401 Leg 1.

Number of Stations
          A total of 33 CTD/rosette stations for PR02 was occupied
using a General Oceanics 12 bottle rosette equipped with 12 2.5-
liter Niskin water sample bottles, and an FSI ICTD. No additional
sensors were used with the CTD system.

Sampling
          The following water sample measurements were made:
salinity, oxygen, nitrate, nitrite and phosphate on all
stations. The depths sampled were: 10, 25, 50, 75, 100, 125,
150, 175, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000,
1250, 1500, 2000, 2500, 3000, 4000 in meters. Surface water
samples were collected by a bucket at every station.

1.3 List of Principal Investigators

          The principal investigators responsible for each parameter
measured on the cruise are listed in Table 1. (All the
correspondence on these data should be addressed to the Director
of the Oceanographical Division, Marine Department, Japan
Meteorological Agency.)



          Name                  Responsibility           Affiliation

          I. Kaneko             CTD, S                   JMA/MD
          K. Fushimi            O2, Nutrients            JMA/MD

          JMA/MD  Marine Department, Japan Meteorological Agency

Table 1. Principal Investigators for all measurements.


2. Measurement Techniques and Calibrations

2.1 CTD

          The CTD is FSI ICTD. An DESKpro 486/33 (Compaq) with 16 
MByte of memory was used as the primary data collection device and
all FSK signals of CTD data were backed up using the digital audio 
tape (DAT). The sampling rate is 32 samples per second. All the 
data were collected and processed same as the Nagasaki Marine 
Observatory does, which were based on Millard and Yang (1993). 

          The temperature and pressure sensor were calibrated at the
calibration facility of FSI Co., Ltd. before the shipping. The
results are shown in Table 2.


                    Temperature; linear fit

                    Time               Bias         Slope
Pre-Cruise (8 October 1993)         +0.0000      1.000000

                    Pressure(increase); linear fit

                    Time               Bias         Slope
Pre-Cruise (7 October 1993)         +0.0000      1.000000

Table 2. CTD Calibration contents at laboratory


          The conductivity sensor was calibrated at sea using data
from the measurements of salinity collected at 13 stations. The
salinometer is Guildline PORTASAL 8410 for the measurements of salinity
of the water samples. The results are shown in Table 3. The
calibration constant is determined assuming that the bias zero.


                                          Bias               Slope

        Stn. 1- 6 (RY8567-8572)            0.0             0.99950
        Stn. 7-11 (RY8573-8577)            0.0             0.99961
        Stn.12-15 (RY8578-8581)            0.0             0.99950
        Stn.16-25 (RY8582-8591)            0.0             0.99942
        Stn.26-33 (RY8592-8599)            0.0             0.99936


Table 3. The conductivity scaling factor

          The temperature in "-.SEA" and "-.CTD" files are described
with the international temperature scale of 1990 (ITS-90).

2.2 Oxygen Measurements

          The determination of dissolved oxygen was done by the
modified version of the Winkler method described in "Kaiyo Kansoku
Shishin (Manual on Oceanographic Observation)" published by the
Japan Meteorological Agency(1970). The reagent blank was not
subtracted. No estimation of accuracy and precision has been done.

          Because no temperature data when samples were taken from
bottles are recorded, it was assumed that the density of samples
is 1022.156 kg/m3 (which assume the temperature for 28 degree C and
salinity for 34.68) and use this value to convert from umol/l to
umol/kg.

2.3 Nutrients Analyses

          The nutrients analyses were done by the Technicon Auto
Analyzer II described in "Kaiyo Kansoku Shishin (Manual on
Oceanographic Observation)" published by the Japan Meteorological
Agency(1970). No estimation of accuracy and precision has been
done.

          Because no temperature data while analyses are recorded,
it was assumed that the density of samples is 1022.156 kg/m3 (which
assume the temperature for 28 degree C and salinity for 34.68) and
use this value to convert from umol/l to umol/kg.

2.4 Noted for the -.SUM, -.SEA and -.CTD files

2.4.1 -.SUM

          Since the surface water samples were taken by a stainless
steel water bucket, "Number of bottle" includes this bucket sampling.

2.4.2 -.SEA

          Our following parameters have the less precision than the
required, we describe the last digit of data as blank to meet the
data format: CTD temperature, CTD salinity, salinity, oxygen and
nitrates. 
          SAMPNO and BTLNBR for the surface water samples taken by 
a bucket is described 0 and -9, respectively.

3. References

Japan Meteorological Agency, 1970: Kaiyo Kansoku Shishin (Manual
          on Oceanographic Observation). (in Japanese)
Millard, R and Keqi Yang, 1993: CTD Calibration and Processing 
          Methods used at Woods Hole Oceanographic Institution.
          Woods Hole Oceanographic Institution Technical Report,
          WHOI-93-44.
