Aquarius Data Release V2.0 Validation Analysis
[17-Apr-2013] Lagerloef, G. and Kao, H-Y.
Presented at the 2013 SMOS-Aquarius Science Workshop
The Aquarius project released V2.0 data in February 2013. This was the first release to have an accompanying validation analysis based on in situ data, along with other supporting documents, whereas previous versions V1.X were for "evaluation" only. For SST > 5C and wind speed < 15m/s, the Aquarius V2.0 data is shown to have a global rms error of ~0.30 psu on 150 km and monthly averages, and ~0.27 psu for seasonal (3-month) averages. The previous publicly released data version (V1.3) had corresponding estimated rms errors of 0.44 and 0.38 psu respectively. The important changes between the two versions include a 0.5 degree pointing angle offset (which affected both geo-location and a number of geophysical models), new antenna gain pattern, and a radiometer calibration correction that applies a secular exponentially decaying gain correction and non-monotonic quasi-monthly offset corrections (aka "wiggles"). It is evident from differences between ascending and descending passes that there are remaining errors with a distinct annual cycle, likely due to the roughness-adjusted galactic reflection coefficient, and regional static errors due to low-level RFI. This presentation will review the current understanding of the V2.0 data and a number of these issues, as well as plans for the next data version, and includes input from several members of the Aquarius team.