Skip to content

RBR

The Hakai RBR CTD Profiles standard processing procedure follows the recommandations provided within the Report Guidelines for processing RBR CTD profiles and RBR recommendations.

The main matlab tool used to process Hakai RBR CTD profiles is maintained and available at hakai-data-tools/ctd-tools/rbr-proc.

Profile Processing Pipeline

For each profiles the following steps executed via the Hakai RBR CTD Processing script:

  1. Convert Ruskin R-Eng Text format to RSKTool compatible format
  2. Correct Sea Pressure for atmospheric pressure:
    1. Use post deployment deck pressure
    2. Use a constant of 10.1325 dbar
  3. Apply auxilliary instrument calibration1
  4. Correct Rinko Data for Ruskin>=2.5,<2.102
  5. Retrieve Static Measurements
  6. Correct Zero-order hold values (Maestro units): Pressure, Temperature and Conductivity
  7. Derive Depth and Profiling Velocity
    1. Derive Depth based on the deployed station latitude.
    2. Derive Profiling velocity from depth filtered with a window length of 3 samples.
  8. Filter Correction
    1. Apply a 0.5s triangle filter on: Temperature and Conductivity
    2. Apply a 1s triangle filter on
  9. Alignment Correction
    1. Conductivity Alignment
      1. 1st Generation Conductivity Cell (black cell): +0.333s
      2. 2nd Generation Conductivity Cell (red cell): +0.04s (Dever e al (2020))3
    2. Dissolved Oxygen
      1. JFE Rinko Sensor: -3.0s
      2. RBR CodaL: Unknown
    3. Turbidity: -0.25s
    4. Fluorescence: -0.25s
  10. Derive Variables
    1. [TEOS-10] Practical Salinity
    2. Dissolved Oxygen Concentration (mL/L) derived from Rinko saturation percentage value by following the conversion equations from Bittig et al. (2018)4 and 4.175s triangle filtered Temperature, Salinity and Pressure values.
  11. Separate up and down cast
  12. Loop Edit Correction:
    1. Minimum Speed: 0.25 m/s
    2. Maximum Deceleration: -0.5đť‘š/đť‘  2
  13. Vertical Bin Average
    1. Bin type: decibar b. Bin size: 1

Static Deployments

A static deployment is a special case where the instrument is maintained at a specific location and depth for a minimum duration.

This type of deployment has been implemented to provide the ability to sample regions associated with very shallow waters.

To be considered as a static measurement, a sample needs to respect the following conditions. The instrument needs to be"

  1. Maintained at a specific location and depth for at least 2 minutes and 30 seconds (We recommend leaving the instrument for at least 3 minutes).
  2. The depth throughout that period can only vary by either 10cm, 33% of the depth or up to 1m, whichever is greater.
  3. The instrument needs to be deeper than 10cm in the water.

  1. This is specific to platforms equipped with Seabird ECO Puck sensors which are outputting data in raw count units ↩

  2. Ruskin 2.5 to <2.10 applied a bad temperature correction to their JFE Rinko sensor and were using a constant temperature value associated to the very first record of temperature record by the CTD unit when the CTD gets turned on and the Rinko units starts outputing good data. The issue was corrected in Ruskin 2.10 but the following section corrects the issue for some of the historical data. ↩

  3. Dever, M., M. Freilich, J. T. Farrar, B. Hodges, T. Lanagan, A. J. Baron, and A. Mahadevan, 2020: EcoCTD for Profiling Oceanic Physical–Biological Properties from an Underway Ship. J. Atmos. Oceanic Technol., 37, 825–840, https://doi.org/10.1175/JTECH-D-19-0145.1. ↩

  4. Bittig et al. (2018): SCOR WG 142 Quality Control Procedures for Oxygen and Other Biogeochemical Sensors on Floats and Gliders. Recommendations on the conversion between oxygen quantities for Bio-Argo floats and other autonomous sensor platforms, DOI 10.13155/45915 ↩