R/V MOANA WAVE (EQ CRUISES) - THERMOSALINOGRAPH DATA R. Lukas (UH, USA) ------------------------------------------------------------------------------- Announced availability: 1 August 1995 Last modified: 11 November 1995 Data Access R/V Moana Wave thermosalinograph data for the COARE Enhanced Monitoring Period mooring maintenance cruises are available from the TOGA COARE International Project Office (TCIPO). Data can be accessed via anonymous FTP from tcdm.coare.ucar.edu in subdirectory pub/COARE_DATA/ocean_mixing/Moana_EQ_tsg. Data are also available upon request from NOAA's National Oceanographic Data Center (NODC) in Washington, D.C. Background Thermosalinograph data were acquired on the COARE EQ1 (17 April 1992 - 14 May 1992), COARE EQ2 (3 - 31 March 1993) and COARE EQ3 (11 April - 8 May 1994) cruises on the R/V Moana Wave. During EQ1 and EQ2, the thermosalinograph was mounted in the pumped intake line for cooling one of the winches. This intake is in the ship's hull in the engine room at ~4 m. Data were acquired at a rate of 1 Hz using a Monserv system connected to a Sun Microsystems workstation. Bottle salinity samples were taken periodically throughout the cruise with the intention of using them to calibrate the conductivity sensor. During EQ3, a Sea-Bird themosalinograph logged temperature and conductivity data every 10 seconds. This thermosalinograph system had a temperature sensor near the bow and an internal temperature sensor near the conductivity sensor that was used to calculate salinity. The unit was installed in the bow chest at a depth of about 3 meters. Data File Information File format The 10-second thermosalinograph ASCII data files contain the following columns: Column 1 (EQ1, EQ2, EQ3): time (decimal Julian day since 1 January 1992) Column 2 (EQ1, EQ2, EQ3): temperature (C) Column 3 (EQ2, EQ3): salinity (psu) FORTRAN Format: (f9.5, f8.4, f9.5) C Format: "%9.5f %7.4f %8.5f" Data Example 108.10771 28.2613 108.10783 28.2625 108.10795 28.2623 108.10806 28.2634 108.10818 28.2645 108.10829 28.2667 108.10841 28.2676 Data Acquisition, Processing and Calibration Calibration The following factory calibrations were used to convert the data to engineering units. EQ1 Temperature: SeaBird sensor number 621 was used. The 20 February 1992 calibration was used to calculate the temperature from the sensor frequency. Assuming that the temperature sensor drifted linearly, the correction was obtained from the 14 August 1986 and the 20 February 1992 calibrations. The correction of 0.0033C was applied. Conductivity: SeaBird sensor number 235 failed on the first day of operation. No spare was available; therefore, no data were acquired or processed. EQ2 Temperature: SeaBird sensor number 621 was used. The post-calibration (19 June 1993) was used. The sensor drift between the previous calibration was calculated to be 0.000025 deg C for the time of the cruise. Since the drift was inconsequential no drift was applied. Conductivity: SeaBird sensor number 375 was used. Coefficients from the 14 January 1993 calibration were applied. No post-cruise calibration was done. Pressure of 20 dbars (assuming the pressure of the pump is 30 psi) was used to calculate salinity. EQ3 Temperature: SeaBird sensor number 1392 was used. The pre-cruise calibration (19 June 1993) was used to convert the data to engineering units. The sensor drift correction was calculated to be 0.0014 deg C at the beginning of the cruise (11 April 1994) and 0.0015 deg C at the end (8 May 1994). Since this variation is very small, 0.0014 deg C was used for the entire cruise. Conductivity: SeaBird sensor number 1392 was used. Coefficients from the 19 June 1993 calibration were applied. Pressure of 3 dbar was used to calculate salinity. Processing Gross error check: Detect out-of-range temperatures and use linear interpolation to replace them. Running median filter: Use a 5-point running median filter to detect temperature glitches. If a glitch is found, the temperature of this record is immediately replaced by the median. Triangular running mean filter: Use a 3-point triangular running mean filter to smooth the edited temperature. Salinity: Calculate salinity assuming pressure including pressure from the pump is 20 dbar. Bottle data: EQ2: The salinity samples were stored in plastic bottles for ~95 days before being analyzed. According to studies done by Sean Kennan these plastic bottles allow the samples to evaporate giving saltier readings. An evaporation rate of 0.05e-3 psu per day was calculated from laboratory tests. This evaporation correction was applied to the data. The thermosalinograph conductivities were corrected using a smoothing cubic spline fit of the bottle-thermosalinograph conductivity time series. EQ3: Water samples were taken three times a day during the entire cruise. Thermosalinograph data corresponding to the time the water samples were taken were compared to the water samples. The thermosalinograph conductivities for each of the two legs were individually corrected using a smoothing cubic spline fit of the bottle-thermosalinograph conductivity time series. ------------------------------------------------------------------------------- For more information, please contact: Roger Lukas Department of Oceanography University of Hawaii 1000 Pope Road MSB # 312 Honolulu, HI 96822 USA e-mail: rlukas@iniki.soest.hawaii.edu Phone: (808) 956-7896 FAX: (808) 956-4104 ------------------------------------------------------------------------------- Reference Shinoda, T., S. DeCarlo, S. Kennan, R. Lukas, F. Santiago-Mandujano, and J. Snyder, 1995: Shipboard Measurements from R/V Moana Wave during TOGA COARE Enhanced Monitoring Cruises. Data Report SOEST-95-07, SOEST, University of Hawaii, Honolulu, HI 96822, 201 pp. ------------------------------------------------------------------------------- www/data/ocean_mixing/moana_eq_tsg.html