I am trying to understand the differences between the oxygen data on OOINet and ERDDAP for Station Papa moorings A and B. These data are not currently available through the Data Explorer.
Here is the OOINet link:
I was only able to access oxygen data for Mooring B. For mooring A, there is no Dissolved Oxygen instrument listed in the Data Catalog.
Here is the ERDDAP link:
I can access both Mooring A and mooring B.
For OOINet, the data for mooring B ends in early 2019. The ERDDAP data for both moorings ends in early 2020 and there are fewer data gaps.
What units are being used for oxygen in the OOINet and ERDDAP datasets (umol/kg or umol/L)? ERDDAP has the variable name ‘mole_concentration_of_dissolved_molecular_oxygen_in_sea_water’ and OOINet has ‘dissolved_oxygen’.
For most of the time-series, the OOINet oxygen is about 25% lower (70 umol/kg or umol/L lower) than the ERDDAP data. What is causing this large offset? Is it because in the OOINet oxygen data, the solubility is calculated assuming a constant salinity and in the ERDDAP oxygen data, the solubility is corrected to the measured salinity?
The O2 data from ERDDAP is showing strange behaviour for both moorings in late 2019 - values are oscillating between high and low oxygen values. For mooring A the difference between the high and low values is around 20 and for mooring B it is around 250. I was hoping to go back to the OOINet raw optode data and see if the issue is present there, but can’t access the data from late 2019 through OOINet.
I’ve attached a figure showing the whole time-series as well as the data from late 2019.
Thanks for your time and assistance.