preliminary data report may 19, 1995 A. Cruise Narrative A.1 Highlights A.1.a WOCE designation PR18 A.1.b EXPOCODE 49TU9107/2 A.1.c Chief Scientist Tomoaki Hinata, NMO A.1.d Ship R/V Chofu Maru A.1.e Port of Call None A.1.f Cruise Dates August 3 to August 10, 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 A.3 List of Principal Investigators Table 1. Principal Investigators for All Measurements Name Responsibility Affiliation ----------------------------------------------- Y. Tomiyama CTD NMO M. Aoyama S,O2,Nutrients NMO H. Nakane Maritime Meteorology NMO ------------------------------------------------ A.4 Scientific Programme and Methods Observations of PR18 were carried on the R/V Chofu Maru Cruise NC9107. The ship sailed from Naha at 0500 UTC on 3 Augist 1991. By 1200 UTC on 3 August the ship was at the first station of a section PR18. The CTD and multisampler were good throughout the cruise. The observations of PR18 ended at 0555 UTC on 6 August. 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 T. Hinata Chief Scientist, NMO CTD Hardware, CTD Software Y. Tomiyama Watch Stander NMO E. Moriyama Watch Standar NMO Y. Takatsuki S,CTD Hardware, NMO CTD Software T. Nakano Watch stander NMO H. Kamiya Watch Stander NMO T. Shimizu O2,Nutrients NMO S. Shiraishi 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 Thermosalinograph and underway dissolved oxygen, fluorometer, etc. B.4 XBT and XCTD B.5 Meteorological observations B.6 Atmospheric chemistry C. Hydrographic Measurements The Neil Brown Mark III B CTD (1600 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 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 tempera- ture 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 12 Mar. 1991 0.0022534 0.9999701 Post-Cruise 10 Jan. 1992 -0.0061256 0.9998243 Pressure increasing (0-1600 dbar range); linear fit Time Bias Slope Pre -Cruise 12 Mar. 1991 -0.0525 0.999349 Post-Cruise 11 Oct. 1991 0.2826 0.999153 ----------------------------------------------------------------- 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 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 sample with the Guildline AUTOSAL 8400A was 0.0007 PSS derived from the standard deviation of the 39 water samples collected from the same bottle on August 7 and 0.009 PSS for 35 water samples on August 8, respectively. Table 4. The conductivity scaling factor ------------------------------------------ Station No. Bias Slope PN-1 - PN-9 - 0.99986 ------------------------------------------ Oxygen measurements The determination of dissolved oxygen was done by the modi- fied 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 precision was generally better than 1 umol/l at the concentration of surface level. No estimation of accuracy has been made. 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 smples were refrigerated and stored up to one hour on every stations during this cruise. 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 5. 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 5. The median and the range ( in the parentheses) of the precision of the onboard nutrients analyses. unit:% Nitrate Nitrite Phosphate ----------------------------------------- 0.52 0.23 0.79 (0.21-1.02) (0.05-0.43) (0.20-1.75) ----------------------------------------- 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 6. Table 6. Laboratory temperature for each station. Station Temp. Station Temp. Station Temp. ------------------------------------------------------- PN-1 26. PN-2 25. PN-3 26. PN-3' 26. PN-4 25. PN-4' 26. PN-5 26. PN-6 24. PN-7 24. PN-8 23. PN-9 23. -------------------------------------------------------- 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; NC9107R.SUM, NC9107R2.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. 5.3 --.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. Acknowledgement 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 tu91072.sum, tu91072.hyd, tu91072.csl and *.wct files. The tu91072.sum file contains a summary of the location, time, type of parameters sampled, and other pertient information regarding each hydrographic station. The tu91072.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 tu91072.wct.zip. The tu91072.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 tu91072.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 Evaulation