The causes of the interannual variability of the Atlantic water inflow to the Arctic Ocean

Abstract:

Recent decline of sea ice in the Arctic Ocean influences the climate system around the Northern polar region. One of the potential reasons of the sea ice decrease is the warming of Atlantic Water, which is transported to the subsurface layer in the Arctic Ocean through the Fram Strait. We utilize a realistically configured OGCM to investigate the mechanisms of the interannual variability of the inflow of the Atlantic water. The horizontal grid size of our model is less than 5 km around the Fram Strait and the Barents Sea Opening. The penetration of warm water to the subsurface layer through the Fram Strait is well reproduced in our model. The eddy activity around the Fram Strait, which enhances the recirculation to the Atlantic Ocean, is also simulated by the horizontally high resolution. Since there is significant correlation between the inflow of the Atlantic Water at the Fram Strait and the NAO index, the synoptic pattern of wind stress is one of the dominant factors on the heat flux between the north Atlantic and the Arctic Ocean. Here we also examine the other causes (e.g., eddy activity and sea surface cooling) of interannual variability of heat flux at the Fram Strait.