Science Meetings

Evolution and Application of the SMOS Level 2 Ocean Salinity Ocean Target Transformation (OTT)
Spurgeon, P. (16-Apr-13)

Soon after launch it became clear there was a consistent and drifting mismatch between SMOS reconstructed L band sea surface temperatures (TBs) and Level 2 processor forward models, due to temporal changes in the instrument and Level 1 performance. To mitigate this the Level 2 OS team decided to apply a snapshot correction (Ocean Target Transformation, OTT)) to Level 1 TBs, generated periodically by smoothing the difference between forward model and Level 1 TBs over a region in the South Pacific ocean where salinity is relatively stable and SMOS measurements are reasonably free from contamination from external sources such as RFI and land.

With over 3 years of continuous data, the temporal and spatial evolution of OTTs will be shown, revealing periodic and long term drift variations driven by external sources (thermal, solar and galactic radiation), and spatial bias patterns due to reconstruction issues. OTTs therefore provide both a diagnostic for Level 1, and a correction for Level 2 in order to successfully retrieve salinity. Analysis and evolution of algorithms for accurate computation and application of OTTs will be presented, together with proposals for more effective correction of real-time ground processing and reprocessing.