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Validation of SMOS and Aquarius Salinity Data in the Agulhas Region
[17-Apr-13] Button, N. and Subrahmanyam, B.
Presented at the 2013 SMOS-Aquarius Science Workshop
Western boundary currents are important to study because they influence regional climates and may impact climate change. The Agulhas Current, in particular, is vital to transport of heat and salt from the Indian Ocean to the Atlantic, especially through Agulhas rings. In order to better understand and assess the role of these rings in the global climate system, accurate measurements of the salinity within the current must be made. This study validates data within the Agulhas region from the recently launched NASA Aquarius/SAC-D salinity mission and ESA's Soil Moisture and Ocean Salinity (SMOS) mission. Argo float data and HYbrid Coordinate Ocean Model (HYCOM) estimates serve as the best in situ and model comparisons to the satellite data respectively. There are approximately 100 Argo floats in the Agulhas Return Current that contribute to the monthly average. The in situ data is important because of its accuracy; however, it lacks in being able to provide spatial and temporal salinity measurements of the entire current. Also, these measurements stop 5- m below surface. The satellite data are able to provide the coverage that Argo data cannot. It is crucial that the satellite data is as accurate as possible within the Agulhas Current for use in for future studies. The data sources were compared by focusing on five regions, both inside and outside of the current. The regions inside the current were compared to the areas of high and low salinity outside of the current. Results show that Aquarius salinity measurements tend to be higher when compared to SMOS measurements as well as both observed (Argo) and modeled values. Through the analysis of the salinity measurements within these regions, this study determined the accuracy of salinity measurements within the Agulhas region from the NASA Aquarius/SAC-D salinity mission and ESA's SMOS mission.

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