An improved inland water detector using standard l1 data: application to cygnss

Earth's inland water detection under thick biomass remains unresolved. Optical sensors are limited by night, clouds and upwelling biomass. The SWAMPS product (active + passive microwave sensors) has a coarse spatial resolution similar to 25 km. C-band Sentinel-1 radar is limited by the upwelling biomass and has a high revisit period. In this work, a new retrieval algorithm based on L1 Cyclone Global Navigation Satellite System (CYGNSS) mission data is developed and results show the capability of water detection under thick biomass similar to 450 ton/ha. The use of the recent IEEE Global Navigation Satellite Systems Reflectometry (GNSS-R) Standard would enable the application of this algorithm by all the present and future GNSS-R missions, and thus generating an unbeatable spatio-temporal sampling by this "virtual" constellation of SmallSats. The capability to accurately resolve surface water extend has an important impact on estimating global methane emissions to the atmosphere.