IMPACT OF THE ELEVATION ANGLE ON CYGNSS GNSS-R REFLECTIVITY OVER DIFFERENT SCATTERING MEDIA OVER LAND AND OCEAN

Earth's surface bistatic reflectivity ΓLHCP,CyGNSS profiles are obtained using Global Navigation Satellite Systems Reflectometry (GNSS-R) products from NASA's Cyclone Global Navigation Satellite Systems (CyGNSS). The focus of this study is to evaluate the influence of the GNSS satellites' elevation angle θe on ΓLHCP,CyGNSS. Specific target areas with differentiated scattering media are selected to characterize these profiles as a function of the land-cover type and the wind-speed regimes for ocean-surfaces. In the former case, the main interest is to further understand the function ΓLHCP,CyGNSS=f(θe,...) in preparation of the potential application of the so-called Tau-Omega model to GNSS-R. In the latter case, the objective is to analyze the impact of the coherent scattering component in GNSS-R observables. Preliminary results show ΓLHCP,CyGNSS increases ~ 3.7 dB over land and ~ 5.3 dB ocean, as θe moves from~ [70], [90]° to ~ [20], [40]°.