This page shows monitoring statistics of surface soil moisture satellite products. It include monitoring of the Advanced SCATterometers ASCAT on METOP-A and METOP-B. ASCAT is a real-aperture radar instrument measuring radar backscatter VV polarisation in the C-band (5.255 GHz). ASCAT surface soil moisture is a EUMETSAT operational product disseminated on EUMETCAST. Its retrieval algorithm is based on a change detection algorithm. Backscattering coefficients are extrapolated to a reference angle at 40Â° and then scaled using the lowest and highest backscattering coefficient values measured over a long period. ASCAT surface soil moisture is a soil moisture index. At ECMWF it is CDF-matched to ECMWF volumetric surface soil moisture range and variability, Monitoring statistics are therefore expressed in volumetric units (m3/m3).