Assessing the retrieval accuracy of SMOS soil moisture product in a Greek agricultural setting

Soil moisture is an important parameter of the Earth system and plays a key role in understanding soil-atmosphere interactions through energy balance and the hydrological cycle. Information on its spatiotemporal variability is of crucial importance in several research topics and applications. Remote sensing, today, provides a very promising avenue towards obtaining information on the variability of soil moisture at varying spatial and temporal resolutions. Also, currently, a number of relevant operational products is available from different satellite sensors.

The objective of the present study has been to evaluate one such product specifically that from the SMOS satellite in a typical Mediterranean setting located in Greece. In particular, this study examines the agreement of the SMOS soil moisture product with collocated field measurements from the Prefecture of Larisa for calendar year of 2020 acquired from Neuropublic S.A.. The agreement between the two datasets was evaluated on the basis of several statistical measures. Also, the effect of topographical and geomorphological features, land use/cover and the relative satellite orbit type and the Radio Frequency Interference (RFI) was examined as part of our analysis.

To our knowledge, this study is one of the few providing an insight of the SMOS soil moisture product accuracy in a Greek setting. Findings of our study can provide important insights towards understanding the practical value of such products in agricultural and arid/semi-arid Mediterranean environments such that of Greece and also help efforts directed towards improving their retrieval accuracy.

Keywords: soil moisture; operational product; remote sensing; SMOS; validation; agriculture; Mediterranean setting