It’s getting hot in here: The Evaluation of Heat Uptake and Release in the Arctic and Impacts on Sea ice Concentration

Abstract:

As the Arctic Ocean loses its sea ice cover, there is a larger oceanic heat gain from the net surface flux throughout the spring and summer; meaning that there is more energy to transfer from the ocean to the atmosphere and outer space in the autumn and winter. Recent work has shown that the increased oceanic heat content at the end of summer delays autumn ice growth, with implications for marine shipping and other economic activities. Depending on patterns of seasonal sea ice retreat and weather conditions, the spring-summer heat uptake and autumn-winter heat loss can be highly variable from year to year and regionally. Here, we examine how the seasonality in upper ocean heat uptake and release has evolved over the period 1979-2018 using three different atmospheric reanalyses (MERRA-2, ERA-5, CFSR) and the relationships between this seasonal change and the evolution of sea ice cover. A statistical relationship is calculated between ocean heat gain, total column water, total cloud cover and sea ice concentration. We determine which regions have seen the largest increases in total seasonal heat uptake and how variable this uptake can be in comparison with an entire Arctic Ocean analysis. What changes have been observed in the rates of seasonal heat uptake and release? Do multiple reanalyses agree with each other with respect to patterns and magnitudes of heat gain and loss? Are there different relationships between surface fluxes and sea ice concentration depending on which reanalysis is used? Do these relationships change when evaluated regionally? In future work, these variables and relationships will be used to construct a statistical model for sea prediction and evaluate which variables have the strongest predictive power.