Abstract:

With the sea ice extent decreasing significantly in recent years, freshwater content(FWC) in the Arctic Ocean has accordingly shown rapid changes. Research on freshwater content variability in the Canada Basin, the main area storing fresh water, has a profound significance for understanding the input-output freshwater in the Arctic Ocean. Based on the data from the Chinese National Arctic Research Expeditions in 2003 and 2008, and the data from expeditions aboard the Canada icebreaker Louis S. St-Laurent （LSSL） in 2004-2007, the FWC in the Canada Basin was calculated. The results showed that the upper ocean in the Canada Basin had been becoming fresher continuously from 2003 to 2008, except for that of 2006. The FWC increased at a rate of more than 1m/yr, and the maximum increase was in the central part of the basin, by 7m, compared between 2003 and 2008. Variability of the FWC was almost limited to the layer above the winter Bering Sea Water (wBSW), below which the FWC was maintained around 3m during this study period. The contributors to the FWC increase were generally considered as the net precipitation, the changes of runoff, the Pacific water inflow through the Bering Strait, the sea ice extent, and the Arctic Oscillation. However, as we determined that the first three contributors did not have apparent impact on the FWC changes, this paper focused on the analysis of the later two factors and the results indicated they were the key contributors to the FWC variability in the basin.

Key words: Freshwater content, Canada Basin, sea ice, Arctic Oscillation(AO)