Mechanisms of the recent sea ice decay in the Arctic Ocean related to the Pacific-to-Atlantic pathway

The sea ice cover in the Arctic Ocean has been reducing and hit the low record in the summer of 2007. The anomaly was extremely large in the Pacific sector. The sea level height in the Bering Sea vs. the Greenland Sea has been analyzed and compared with the current meter data through the Bering Strait. A recent peak existed as a consequence of atmospheric circulation and is considered to contribute to inflow of the Pacific Water into the Arctic Basin. The timing of the Pacific Water inflow matched with the sea ice reduction in the Pacific sector and suggests a significant increase in heat flux. The other component is the Arctic Dipole Mode (ADM) as the second EOF of sea level pressure with dipoles over Siberia and Canada at opposite signs. In last 50 years, the Pacific sector had low ice cover at a 1–2 year lag from the ADM with a low pressure over Siberia. Since this mode was extremely intense in 2007 summer, the sea ice is predicted to be low in 2008. It has been claimed that most projections underestimate sea ice reduction in the Arctic during this century. Our tasks include removal of possible biases due to different sensors and accurate estimates of the important feedbacks contained in the atmosphere-ice-ocean system. Then, an answer will be found for the questions when the Arctic sea ice becomes a seasonal ice cover.