Author(s): Li Qun; Lei Ruibo
Keywords: No Keywords
Abstract: It has been revealed that large scale atmospheric forcing can only partly explain the dramatic decline of summer sea ice extent and thickness in the past decades, while other contributions are likely come from the upper ocean thermal-dynamic process. In this talk, we investigated the lifecycle of summer mesoscale warm-core eddy in the Western Arctic Ocean and its role on the upper ocean heat redistribution. The model used here is the finite-element global ice-ocean coupled model (FESOM), and a global configuration with regional focus on the western Arctic is implemented. Benefit from the finite element technology and its flexible refinement properties, the regional focus region reachededdy-resolving. Special attention is paid to the summer Alaskan Coastal current (ACC), which has a high temperature (up to 5℃ or more) in the upper layer due to the solar radiation over theopen water in the lower latitude. Downstream of the ACC after Barrow Point, surface-intensified anticyclonic eddy with warm-core is frequently generated and propagate towards the Canada basin during the summer season when sea ice has retreated away from the coast. Such kind warmcore eddy has tremendous heat content and a more direct impact on the sea ice, compared with other eddy types. Spiral structure of sea ice is similar to that seen in satellite images of this region, and is a reflection of the eddy process. The sea ice melt induced by such eddies is very efficient, since a high spiral velocity together with increased temperature gradient could increase heat transfer between ice and ocean.