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This repository contains the code to post-process data from RBR CTDs on Argo floats

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This repository contains the code to post-process data from RBRargo|2k CTDs on Argo floats. Users are invited to consult Argo Quality Control Manual For CTD and Trajectory Data (DOI: 10.13155/33951), where more details are provided on how to properly use these tools.

These DMQC tools are provided "as is" to the community and should be used with caution and knowledge of their requirements. Both Python and MATLAB codes are made available.


For RBRargo|2k CTDs calibrated before April 2021, an additional correction must be applied to PSAL to account for compressibility errors. This repository includes:

  • A database RBRargo3_compressibility_table.csv listing the affected RBRargo|2k CTDs, along with the new calibration coefficients to be used.
  • A routine RBRargo_compressibility that relies on the database mentioned above to automatically apply the compressibility correction if necessary.
  • A routine RBRargo_compressibility_example that shows an example on how RBRargo_compressibility can be used.


The variable TEMP_CNDC on RBRargo|2k CTDs corresponds to the temperature measured internally to the conductivity cell. It is a necessary variable to be able to correct for the long-term thermal inertia of the conductivity cell. If the variable is non-present, or the data quality is bad, TEMP_CNDC can be infered using the temperature history measure by the marine thermistor (TEMP variable) along with an IIR filter. Repository includes:

  • A routine RBRargo3_TEMP_CNDC_from_TEMP_ADJUSTED that reconstructs the TEMP_CNDC using a recursive filter described in Lueck and Picklo (1990).
  • A routine RBRargo3_TEMP_CNDC_from_TEMP_ADJUSTED_example that shows an example on how RBRargo3_TEMP_CNDC_from_TEMP_ADJUSTED can be used.

Thermal inertia

Thermal inertia errors in conductivity measurements can be corrected using a combination of corrective algorithms, extensively described in Dever, Owens, Richards, Wijffels, Wong, Shkvorets, Halverson, and Johnson (2022)(DOI: 10.1175/JTECH-D-21-0186.1) Repository includes:

  • A routine RBRargo3_celltm that computes the thermal error associated with the thermal inertia of the conductivity cell (TEMP_celltm)
  • A routine RBRargo3_celltm_example that shows an example on how RBRargo3_celltm can be used.


In January 2024, RBR discovered an inconsistency between salinity readings reported by an instrument while streaming and the salinity readings calculated by Ruskin with the downloaded data (RBR Report RBR#0016488revA). The root cause of the discrepancy between the onboard calculated and the Ruskin calculated salinity was quickly attributed to an approximation in the square root calculation onboard the instrument. The error can be adjusted for in post-processing using the set of routines provided in the SQRT_adjustment folder. Repository includes:

  • A routine correct_sqrt_error that adjusts the salinity data for the square root discrepancy
  • A routine correct_sqrt_error_testcase that shows an example on how correct_sqrt_error can be used.


This repository contains the code to post-process data from RBR CTDs on Argo floats







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