SMOS and Aquarius Salinity Measurements and Validation in the Indian Ocean
[17-Apr-13] Subrahmanyam, B., Nyadjro, E., and Felton, C.
Presented at the 2013 SMOS-Aquarius Science Workshop
The non-availability of global-scale salinity observations has been a challenge in many studies that require salinity data. The Aquarius salinity mission is currently providing complete global coverage of sea surface salinity (SSS) measurements with a temporal resolution of 7 days. In this study, we assess the validity of preliminary Aquarius salinity measurements in the Indian Ocean by comparing it to the Soil Moisture and Ocean Salinity (SMOS) mission SSS, Argo float SSS data and the 1/12 high resolution HYbrid Coordinate Ocean Model (HYCOM) SSS output. Comparisons of Aquarius passes with HYCOM, SMOS, and Argo indicate Aquarius is performing better than the SMOS mission for daily measurements. However, contamination of SSS measurements still occurs at this resolution. Analysis of monthly Aquarius data with other SSS measurements indicates Aquarius is highly correlated with HYCOM and Argo in the open ocean and on average, the differences in SSS rarely exceed above 0.4 psu at this temporal resolution. Aquarius SSS is able to capture the salinity features and distribution in the Indian Ocean. Notably among these are the high SSS in the Arabian Sea, the low SSS in the Bay of Bengal and the low salinity tongue from the Indonesian Throughflow (ITF). Boxed-averaged comparison of salinity differences and root mean square error statistic suggested that the most differences between the salinity products occur in the Bay of Bengal, possible the consequence of high salinity variability, precipitation and river runoff in that region.