Two Modes of Interaction of the Atmosphere and the Ocean in the Atlantic Sector of the Arctic Basin
The paper examines the influence of the main mode of interannual variability of the North Atlantic climate system – the North Atlantic Oscillation (NAO) – on the hydrophysical and hydrometeorological characteristics of the Nordic Seas. A new scheme of the ocean–atmosphere interaction in the Atlantic sector of the Arctic basin is proposed. In the positive phase of the NAO, the volume of Atlantic water inflow through the Faroe-Shetland Canal into the Norwegian Sea decreases, as well as their specific heat transfer to the atmosphere. Cyclonic activity over the marginal seas of the Euro-Asian shelf in winter in the positive phase of the NAO becomes more active. Cyclone trajectories are displaced to the north, which contributes to the advection of warm air to the water area of the Nordic Seas, and in the Barents Sea region, the frequency of southerly winds increases. The water temperature in this period in the Nordcape Current rises, and the ice extent of the Barents Sea decreases. The processes in the ocean–atmosphere–ice system of the Western Arctic in the negative phase of the NAO proceed in the opposite direction. These conclusions were obtained for a time interval characterized by negative values of the Atlantic Multi-Decade Oscillation (AMO index). During the positive phase of AMO, which began to prevail in the 2000s, the processes in the ocean–atmosphere–ice system of the Barents Sea occurred, apparently, mainly under the influence of the advection of Atlantic waters of elevated temperature.