Exploring the potential of SCAT-SAR SWI for soil moisture retrievals at selected COSMOS-UK sites

ABSTRACT

The need for information on soil moisture at large scale to facilitate a sustainable intensification of agricultural land and to ensure food security due to increasing populations cannot be overstated. Remote sensing provides a platform for potential national coverage of soil moisture monitoring. This study explores the potential for using a Synthetic-Aperture-Radar Soil Water Index (SCAT-SAR SWI) product as a method of accurately monitoring soil moisture across the UK by comparing its output with the COSMOS-UK cosmic-ray soil moisture observation network. Using the daily data from these stations, SWI data from SCAT-SAR were compared during 2015 for the UK. Five COSMOS-UK network sites were selected across the UK for assessment, and the respected SCAT-SAR SWI pixels were extracted for their soil moisture values. Statistical test that were computed allowed quantifying the correlation between the truth data of the TDT soil moisture sensors and the COSMOS and SCAT-SAR soil moisture product. It was found that the SCAT-SAR product consistently underestimated the soil moisture with elevation affecting the level of agreement. The COSMOS network slightly overestimated soil moisture but was found, at least in this study, noticeably more accurate than the SCAT-SAR. The RMSD of the SCAT-SAR product was noticeably higher at sites with the highest elevation.

Acknowledgements

Authors thank Centre for Ecology & Hydrology (CEH) for the provision of theASAR-SCAT product version available the period this study was conducted. GPP’s contribution has been funded by a UK Research Council award (STFC ST/N006836/1) and the author gratefully acknowledges this financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).