The Arctic Ocean response to the North Atlantic oscillation

The climatically sensitive zone of the Arctic Ocean lies squarely within th e domain of the North Atlantic oscillation (NAO), one of the most robust re current modes of atmospheric behavior. However, the specific response of th e Arctic to annual and longer-period changes in the NAO is not well underst ood. Here that response is investigated using a wide range of datasets, but concentrating on the winter season when the forcing is maximal and on the postwar period, which includes the most comprehensive instrumental record. This period also contains the largest recorded low-frequency change in NAO activity-from its most persistent and extreme loa index phase in the 1960s to its most persistent and extreme high index phase in the late 1980s/early 1990s. This long-period shift between contrasting, NAO extrema was accompa nied, among other changes, by an intensifying storm track through the Nordi c Seas, a radical increase in the atmospheric moisture flux convergence and winter precipitation in this sector, an increase in the amount and tempera ture of the Atlantic water inflow to the Arctic Ocean via both inflow branc hes (Barents Sea Throughflow and West Spitsbergen Current), a decrease in t he late-winter. extent of sea ice throughout the European subarctic, and (t emporarily at least) an increase in the annual volume flux of ice hom the F ram Strait.