Integrated retrieval of sea-ice salinity, density, and thickness using polarimetric GNSS-R

This study presents a novel methodology for estimating sea-ice thickness (SIT) using polarimetric Global Navigation Satellite System – Reflectometry (GNSS-R). Building on previous work that demonstrated the capability of GNSS-R to measure thin sea ice, this research extends the application to thicker and multi-year sea ice using data from the Soil Moisture Active Passive (SMAP) mission. The study employs three key datasets: polarimetric GNSS-R data from SMAP, sea-ice thickness data from CryoSat-2 and SMOS, and ice temperature data from ERA5. A detailed model correlating the GNSS-R reflectivity to SIT and incorporating the impact of sea-ice salinity is developed. Results show high correlation coefficients between the GNSS-R derived parameters and the CryoSat-2/SMOS SIT data, indicating the method's robustness. The study concludes that full polarimetric GNSS-R can be useful to estimate sea ice salinity and density, critical to improve SIT models for its use in GNSS-R, other radar, and microwave radiometry instruments.