No abstract

Turbulent heat transfer from surface to atmosphere is important in the atmospheric energy balance over the Arctic, thereby impacting the remarkable warming that occurs in this region. The impact of heat transfer over the Arctic land and sea (approximate Arctic Ocean) on Arctic warming could be distinct, owing to different heat sources and physical processes on the interfaces. This study sought to analyse the heat transfer and changes over the Arctic land and sea and their contributions to those over the entire Arctic, and discuss the connection between the heat transfer changes and Arctic warming based on ERA5 reanalysis. The Arctic surface releases heat to the atmosphere, with an annual average of 4.5 × 10 14 W, which is mainly contributed by the Arctic land in summer and sea in winter. From 1979 to 2018, the amount of heat release was found to markedly increase, with an annual trend of 0.94 ± 0.31 W/(m 2 decade). A faster increase occurred in summer and was contributed by both the Arctic land and sea. In contrast, a slower increase occurred in winter and was only contributed by the sea. The heat transfer changed heterogeneously over the Arctic land and sea, with three major changes: Northern Russia Increase over northern Russia in summer, Northern Barents Increase over the northern Barents Sea in winter, and Nordic Sea Decrease over the Nordic Sea and northern Greenland Sea in winter. Notably, the heat transfer change over the Arctic land and sea could be connected to Arctic warming, especially the three major changes, based on distinct feedback processes, which could impact future Arctic warming. Overall, the Arctic land and sea play distinct roles in the heat transfer change and connection to Arctic warming, with the land being more important in summer and the sea being more important in winter.