Changes in The Seasonality of Sea Ice and The Underlying Mechanisms Across Hudson Bay (HB) from 1979-2018

Sea ice in Hudson Bay (HB) holds great importance ecologically, climatologically, economically, and for the Inuit culture. It has been widely established that sea ice seasons: Break-Up (BU), Ice-Free (IF), Freeze-Up (FU) and Ice-Covered (IC) have been shifting, but the underlying mechanisms remain unknown. Energy and Radiation Budget data-set was downloaded from North American Regional Reanalysis (NARR). The analysis has revealed that over the past 40 years, ocean energy exchange is sensitive to astronomical cycles. As the timing of the BU season shifts away from the summer solstice toward the spring equinox the strength of the ice-albedo feedback weakens, slowing the melt of ice. As the IF season is lengthening primarily into the fall/winter, the benefits of low albedo are diminished and the trend is toward net energy loss. Overall, this research fills important gaps in understanding the duration and energetics of each ice season. It also addresses the limitations of NARR albedo data in studying sea ice.