Sensitivity of Sentinel-1 to Rain Stored in Temperate Forest

The sensitivity of radar backscatter to the amount of intercepted rain in a Douglas-fir and a beech stand was analyzed to determine the feasibility of retrieval canopy storage capacity from Sentinel-1 (C-band). On average, backscatter of a wet Douglas-fir canopy is ~1.5 dB and ~1 dB higher than the backscatter when the canopy is dry at VH and VV polarization respectively. No consistent differences were found in the case of the beech stand between wet and dry conditions. It is argued that the use of Sentinel-1 to retrieve the amount of intercepted rainfall is limited at best to a reliability of 50% and to canopies with large storage capacity.