HR: 0800h
AN: OS31A-0563    [Abstracts]
TI: Cruise Summary of WHP P6, A10, I3 and I4 Revisits in 2003
AU: * Kawano, T
EM: kawanot@jamstec.go.jp
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Uchida, H
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Schneider, W
AF: Universidad de Concepcion, Departamento de Oceanografia, Barrio Universitario S/N,, Cabina 5, Concepcion Chile
AU: Kumamoto, Y
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Nishina, A
AF: Faculty of Fisheries, Kagoshima University, 4-50-20, Shimoarata, Kagoshima, 890-0056 Japan
AU: Aoyama, M
AF: Meteorological Research Institute, 1-1, Nagamine, Tsukuba, 305-0052 Japan
AU: Murata, A
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Sasaki, K
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Yoshikawa, Y
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Watanabe, S
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AU: Fukasawa, M
AF: JAMSTEC, 2-15, Natsushima, Yokosuka, 237-0061 Japan
AB: Japan Agency for Marin-Earth Science and Technology (JAMSTEC) conducted a research cruise to round in the southern hemisphere by R/V Mirai. In this presentation, we introduce an outline of the cruise and data quality obtained during the cruise. The cruise started on Aug. 3, 2003 in Brisbane, Australia and sailed eastward until it reached Fremantle, Australia on Feb. 19, 2004. It contained six legs and legs 1, 2, 4 and 5 were revisits of WOCE Hydrographic Program (WHP) sections P6W, P6E, A10 and I3/I4, respectively. The sections consisted of about 500 hydrographic stations in total. On each station, CTD profiles and up to 36 water samples by 12L Niskin-X bottles were taken from the surface to within 10 m of the bottom. Water samples were analyzed at every station for salinity, dissolved oxygen (DO), and nutrients and at alternate stations for concentration of freons, dissolved inorganic carbon (CT), total alkalinity (AT), pH, and so on. Approximately 17,000 samples were obtained for salinity. The standard seawater was measured repeatedly to estimate the uncertainty caused by the setting and stability of the salinometer. The standard deviation of 699 repeated runs of standard seawater was 0.0002 in salinity. Replicate samples, which are a pair of samples drawn from the same Niskin bottle to different sample bottles, were taken to evaluate the overall uncertainty. The standard deviation of absolute differences of 2,769 replicates was also 0.0002 in salinity. For DO, about 13,400 samples were obtained. The analysis was made by a photometric titration technique. The reproducibility estimated from the absolute standard deviation of 1,625 replicates was about 0.09 umol/kg. CTD temperature was calibrated against a deep ocean standards thermometer (SBE35) which was attached to the CTD using a polynomial expression Tcal = T - (a +b*P + c*t), where Tcal is calibrated temperature, T is CTD temperature, P is CTD pressure and t is time. Calibration coefficients, a, b and c, were determined for each station by minimizing the sum of absolute deviation from SBE35 temperature below 2,000dbar. CTD salinity and DO were fitted to values obtained by sampled water analysis using similar polynomials. These corrections yielded deviations of about 0.0002 K in temperature, 0.0003 in salinity and 0.6 umol/kg in DO. Nutrients analyses were accomplished on 16,000 samples using the reference material of nutrients in seawater (RMNS). To establish the traceability and to get higher quality data, 500 bottles of RMNS from the same lot and 150 sets of RMNSs were used. The precisions of phosphate, nitrate and silicate measurements were 0.18 %, 0.17 % and 0.16 % in terms of median of those at 493 stations, respectively. The nutrients concentrations could be expressed with uncertainties explicitly because of the repeated runs of RMNSs. All the analyses for the CO${2}$-system parameters in water columns were finished onboard. Analytical precisions of CT, AT and pH were estimated to be \sim1.0 umol/kg, \sim2.0 umol/kg, and \sim7*10$^{-4}$ pH unit, respectively. Approximately 6,300 samples were obtained for CFC-11 and CFC-12. The concentrations were determined with an electron capture detector - gas chromatograph (ECD-GC) attached the purge and trapping system. The reproducibility estimated from the absolute standard deviation of 365 replicates was less than 1% with respect to the surface concentrations.
DE: 4215 Climate and interannual variability (3309)
DE: 4271 Physical and chemical properties of seawater
DE: 4294 Instruments and techniques
DE: 4299 General or miscellaneous
DE: 4500 OCEANOGRAPHY: PHYSICAL
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting