CYGNSS GNSS-R Data for Inundation Monitoring in the Brazilian Pantanal Wetland

Global Navigation Satellite System Reflectometry (GNSS-R) that uses signals of opportunity in L-band microwave frequency is an optimal system for Earth surface remote sensing. Spaceborne GNSS-R is a very promising bistatic radar system to detect, estimate and monitor inundation extents as it collects GNSS reflections in a good spatiotemporal resolution and is not affected by clouds and, to some extent, aboveground vegetation. In this contribution, we propose a new method to estimate the inundation extent of the Brazilian Pantanal wetland using three years (Aug. 2018 - Jul. 2021) of data from NASA Cyclone GNSS (CYGNSS) mission. The proposed method is independent in variations of the transmitted signal power and angle of incidence as the inundation extent is estimated track by track. We find very good agreement between the GNSS-R inundation extent retrievals and those derived from different remote sensing techniques with a correlation of 0.92.