MIRAI MR05-01 Conductivity-Temperature-Depth Profiler (CTD) Calibration

  1. Sensors
  2. • Water Temperature (Type : SBE3, S/N : 031525)
    (a) Calibration date
    Pre-calibration : 13 Jan.,2005 at SBE T-sensor
    Post-calibration: 19 Apr.,2005 at SBE T-sensor
    (b) Drift
    0.00081 degrees-C/year
    (c) Estimated error
    As presented above, the drift rate for temperature is calculated from pre and post calibrations as 0.00081 degrees-C/year. Hypothesizing the linearity in T-sensor drift, the error of water temperature is tried to estimate using the drift rate.
    From pre-calibration date, 13 Jan.,2005 until the last day of MR05-01 on 24 Mar.,2005, it takes about 0.19 year. Then the error of water temperature data observed by CTD is estimated as 0.0002 degrees-C for the cruise of MR05-01.

    • Salinity (Type : SBE4, S/N : 042240)
    (a) Calibration date
    Pre-calibration : 15 Jan.,2005 at SBE C-sensor
    Post-calibration: 28 Jul.,2005 at SBE C-sensor
    (b) Drift
    0.0000 PSU/month

    • Pressure (Type : SBE9plus, S/N : 42423)
    Calibration date, coefficients
    The calibration coefficients for the sensor are as follows;
    Pre-calibration : 28 Apr.,2004 at JAMSTEC slope1: 0.9999312 , offset1: 0.1400218
    Post-calibration: 05 Apr.,2005 at JAMSTEC slope2: 0.9999566 , offset2: 0.1851940
    The observed value is computed as
    Observed value [dbar] = slope1 * computed pressure[dbar] + offset1[dbar]

    • Pressure (Type : SBE9plus, S/N : 79492)
    Calibration date, coefficients
    The calibration coefficients for the sensor are as follows;
    Pre-calibration : 30 Jul.,2004 at JAMSTEC slope1: 0.9999004 , offset1: 0.9452709
    Post-calibration: 18 Apr.,2005 at JAMSTEC slope2: 1.0000630 , offset2: 0.8195010
    The observed value is computed as
    Observed value [dbar] = slope1 * computed pressure[dbar] + offset1[dbar]

    • Dissolved Oxygen (Type : SBE43, S/N : 430394)
    (a) Calibration date
    Pre-calibration : 01 Feb.,2005 at SBE D.O.-sensor
    Post-calibration: 04 Jun.,2005 at SBE D.O.-sensor
    (b) Drift
    -68.3707 ml/l /year
    (c) Estimated error
    As presented above, the drift rate for dissolved oxygen is calculated from pre and post calibrations as -68.3707 ml/l /year. Hypothesizing the linearity in D.O.-sensor drift, the error of dissolved oxygen is tried to estimate using the drift rate.
    From pre-calibration date, 01 Feb.,2005 until the last day of MR05-01 on 24 Mar.,2005, it takes about 0.14 year. Then the error of dissolved oxygen data observed by CTD is estimated as -9.572 ml/l for the cruise of MR05-01.

    • Dissolved Oxygen (Type : SBE43, S/N : 430205)
    (a) Calibration date
    Pre-calibration : 21 Sep.,2004 at SBE D.O.-sensor
    Post-calibration: 10 May, 2005 at SBE D.O.-sensor
    (b) Drift
    0.0638 ml/l /year
    (c) Estimated error
    As presented above, the drift rate for dissolved oxygen is calculated from pre and post calibrations as 0.0638 ml/l /year. Hypothesizing the linearity in D.O.-sensor drift, the error of dissolved oxygen is tried to estimate using the drift rate.
    From pre-calibration date, 21 Sep.,2004 until the last day of MR05-01 on 24 Mar.,2005, it takes about 0.50 year. Then the error of dissolved oxygen data observed by CTD is estimated as 0.032 ml/l for the cruise of MR05-01.

  3. Comparison with sampled water analysis
  4. The comparison between the CTD measurement and the bottle measurement can be used on the following pages.