Dataset: Biofloat_48 Optode dissolved oxygen sensor Profiles
Deployment: Biofloat_48

Dissolved oxygen (parameter names O2_cal): The Seabird SBE-43 oxygen sensor and the Aanderra Optode on float 48 both require calibration and removal of various sensor errors. The Optode is poorly calibrated in terms of dissolved oxygen, temperature and pressure.  During times of low flow and a closed drogue, it can have biases exceeding 10 μmol/kg, probably due to oxygen consumption by the float.  The SBE-43 exhibits mode-variable biases due to our attempts to reduce pumping energy.  By inter-comparing these sensors and comparing them with the Winkler bottle samples from the R/V Knorr and SBE-43 sensor taken on calibration casts during R/V Knorr cruise 193-03, adjustments were developed to bring both float 48 oxygen sensors and the R/V Knorr CTD SBE-43 sensor into agreement and into absolute calibration to an accuracy of better than 2 μmol/kg.  These corrections are applied to the float data. The best float 48 oxygen data was obtained from the SBE-43 in all float modes and the Optode in down and drift modes. The Optode data from settle and up mode still contains systematic errors.   For more details, see Oxygen_Calibration-NAB08.pdf.

<p>Dissolved oxgyen (O2_cal) was cross-calibrated with RV Knorr's SBE43 sensor and Winkler oxygen during KN193-03.&nbsp; Oxygen saturation value (O2sat) was computed using temperature and salinity (Garcia and Gordon, 1992.)</p>