Toward an understanding of Arctic cloud-sea ice feedbacks from observations

Arctic sea ice extent has decreased dramatically over the last thirty years, and this trend is expected to continue through the 21st century. Changes in sea ice extent impact cloud amount. In September 2007, sea ice extent reached a record low for the satellite period, which began in the 1970s. Significantly positive cloud amount anomalies occurred over the newly opened water, which in turn influence the surface energy budget. To what extent do changes in sea ice cover influence cloud amount and vice versa? Here we assess the feedback between Arctic cloud amount and sea ice extent using satellite products and reanalysis data from 2000 to the present, including MODIS cloud amount, sea ice concentration from SSM/I, and NCEP reanalysis. Lead/lag correlations are used to infer cloud-sea ice interaction. In the Arctic, MODIS cloud amount varies accordingly with NCEP cloud amount, though they have very different absolute values. Positive cloud amount anomalies correspond to the newly opened water, particularly in autumn. Cloud amount anomalies are correlated with anomalies in relative vorticities at 850 hPa, which implicates the close relationship between cloud amount and large-scale circulation. A statistical method is also applied to quantify the cloud feedback on the Arctic climate. The feedback efficiency of cloud on the sea ice and Arctic climate will be presented.