The impact of combining SMOS and ARGO data on the SMOS Level 2 and 3 products and effect of the vicinity of the coast

The SMOS (Soil Moisture and Ocean Salinity) Mission is the second of the ESApsilas Living Planet Programme Earth Explorer Opportunity Missions and it is scheduled for launch on November 2008. Its objective is to provide global and frequent Soil Moisture (SM) and Sea Surface Salinity (SSS) maps. SMOSpsila single payload is the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS) sensor, an L-band two-dimensional aperture synthesis interferometric radiometer. To help in the retrieval process, auxiliary data must be used in combination with the brightness temperatures measured by MIRAS. The output products of SMOS at Level 3 will be SSS remote measurements with global coverage and an accuracy of 0.1-0.4 psu (practical salinity units) over 100 x 100 - 200 times 200 km² in 30 - 10 days. In this study pseudo SMOS Level 3 Products have been obtained in order to test the impact at Level 3 of introducing ARGO salinity measurements in the SMOS data processing chain. To do so: 1) The Ocean Parallelise (OPA) Model has been run to provide geophysical parameters; 2) The SMOS End-to-end Processor Simulator (SEPS) has been used to compute the brightness temperatures as measured by the MIRAS; 3) The SMOS Level 2 Processor Simulator (SMOS-L2PS) has been applied to retrieve SSS values for each point and overpass. To asses also the possible impact of the coastal vicinity effect, two different zones have been simulated; the first one in open ocean and the second one in a coastal region, near the Canary islands (Spain) where SMOS and Aquarius CAL/VAL activities are foreseen. The results for both simulation scenarios are presented and discussed.