Comparison between high and coarse spatial resolution surface soil moisture products over two Mediterranean sites in Tunisia and France

The surface soil moisture (SSM) is an essential component in hydrologic modelling. Therefore, an accurate retrieval of SSM with high repetitiveness in time and space will improve the hydrologic performance. In the present paper, we compare between 1-km SSM product available every 6 days (HRSM) with operational SSM products namely Soil Moisture Active and Passive (SMAP) and ESA CCI combined (CCI) characterized with coarse spatial resolution and high revisit time up between 1 and 3 days over two Mediterranean sites in Tunisia and Occitanie in France. The analyses of SSM time series are performed as function of SSM product date in first step and monthly in a second step. The results revealed that HRSM time series, over the two sites, are in coherence with SMAP and CCI time series and marked by seasonality from one year to another (2017-2021). Over the Occitanie site, the comparison between HRSM monthly averages and the SMAP and CCI averages is characterized by an RMSE values varying between 5 and 9.8 vol.%, respectively. The RMSE values decreased, over Tunisia, and reached a maximum of 5 vol.%. The aforementioned findings underlined the potential of 1-km product to be included in future applications such as drought identification.