Multi-temporal monitoring of salinity in Eastern Mediterranean Region using SMOS L2 OS satellite data and in situ measurements

Περίληψη

This study has been motivated to assess, for the first time, the performance of Sea Surface Salinity, SSS of the Soil Moisture and Ocean Salinity (SMOS) satellite launched by the European Space Agency (2009), on the Mediterranean Region. The SMOS satellite is a microwave radiometer which records at 1.4 Ghz frequency and at a wavelength l = 21cm, the microwave radiation emitted from the surface of the oceans. The physical properties of the sea water, salinity and temperature are the key factors that need to be constantly monitored. This constant monitoring contributes to a better understanding of the motion of ocean currents. Ocean currents transfer a large amount of heat from the equatorial regions to the poles, sustaining this way the global climate. Until recently the monitoring of salinity and temperature, took place mainly by ship measurements and monitoring stations (Buoys) located in the open ocean, which were sparse, regional and highly costly to maintain. The SMOS mission launched in November 2009, would record for the first time the soil moisture and ocean salinity from space. The missions objective is the global observation of salinity with a monthly accuracy of 0.1 psu. The data used for the study are L2 OS gridded in bins of 0.5° in latitude and longitude (by Reul, N.) and in-situ data provided by the Hellenic Centre of Marine Research/HCMR and the POSEIDON project. The area of interest is the East part of the Mediterranean (Fig.1) and both the satellite and in-situ data cover a period of three years (2010-2012). Due to the absence of Buoys in the broader area of East Mediterranean, hydro dynamical forecasting models were used provided by the HCMRs Live Access Server/LAS portal for the comparison of the data. The results of the study show very poor quality of SMOS-derived SSS values due to land contamination and RFI emissions.