[09-Mar-2020] Tang, W. et al. . Hudson Bay (HB) is the largest semi-inland sea in the Northern Hemisphere, located at the southern margin of the Arctic Ocean. The bay is completely covered by ice and snow in winter, and open water in summer. For about six months each year, satellite remote sensing of sea surface salinity (SSS) is retrieved over open water. SSS links freshwater contributions from various processes. Given the strategic importance of HB, SSS has great potential in monitoring the HB freshwater cycle and studying its relationship with climate change. However, SSS retrieved in polar regions from currently operational space-based L-band microwave instruments has large uncertainty (~1 psu) mainly due to sensitivity degradation in cold water (<5C) and sea ice contamination. Given this large uncertainty, we explore the potential use of satellite SSS in monitoring HB freshwater cycle.