Relation between GG-R Carrier Phase Signal Coherency and Sea ICE Concentration over Hudson Bay

This study presents a comparison of Spire Global, Inc. carrier phase Global Navigation Satellite System-Reflectometry (GNSS-R) dual-frequency signals under grazing angle (GG-R) signal coherency and altimetric retrievals, with ice concentration from January to October 2021 over the Hudson Bay region. Monthly analysis reveals higher coherency during periods when ice is present. Additionally, a greater number of retrievals are derived from January to May (winter) compared to the period from July to October (summer), with the exception of July, which exhibits exceptionally larger coherency. The comparison between summer and winter periods show a difference of approximately 6 cm in Root Mean Square Error (RMSE) and 21 cm of standard deviation between the reference surface model and the GG-R altimetry results. Moreover, there are 62% fewer retrievals from January to October in the months with no ice presence.