The Role of Moisture Transport for Precipitation on the Interannual and Inter-Daily Fluctuations of the Arctic Sea Ice Extension

By considering the moisture transport for precipitation (MTP) for a target region to be the moisture that arrives in this region from its major moisture sources and which then results in precipitation in that region, we explore i) whether the MTP from the main moisture sources for the Arctic region are linked with interannual fluctuations in the extent of Arctic Sea ice superimposed on its decline and ii) the role of extreme MTP events in the inter-daily change of the Arctic Sea Ice Extent (SIE) when extreme MTP simultaneously arrives from the four main moisture regions that supply it. The results suggest 1) that ice-melting at the scale of interannual fluctuations against the trend is favoured by an increase in moisture transport in summer, autumn, and winter, and a decrease in spring and, 2) on a daily basis, extreme humidity transport increases the formation of ice in winter and decreases it in spring, summer and autumn; in these 3 seasons it therefore contributes to Arctic Sea Ice Melting. These patterns differ sharply from that linked to the decline, especially in summer when the opposite trend applies.