Connecting early summer cloud­controlled sunlight and late summer sea ice in the Arctic

Abstract

This study demonstrates that absorbed solar radiation (ASR) at the top of the atmosphere in early summer (May-July) plays a precursory role in determining the Arctic sea ice concentration (SIC) in late summer (August-October). The monthly ASR anomalies are obtained over the Arctic Ocean (65°N-90°N) from the Clouds and the Earth's Radiant Energy System during 2000-2013. The ASR changes primarily with cloud variation. We found that the ASR anomaly in early summer is significantly correlated with the SIC anomaly in late summer (correlation coefficient, r - 0.8 with a lag of 1 to 4 months). The region exhibiting high (low) ASR anomalies and low (high) SIC anomalies varies yearly. The possible reason is that the solar heat input to ice is most effectively affected by the cloud shielding effect under the maximum TOA solar radiation in June and amplified by the ice-albedo feedback. This intimate delayed ASR-SIC relationship is not represented in most of current climate models. Rather, the models tend to over-emphasize internal sea ice processes in summer.