Interannual variability in water masses in the Greenland Sea and adjacent areas

Oceanographic data covering the period 1950-1998 are used to determine interannual variations in the convection intensity and water mass structure in the Greenland Sea and adjacent areas. Extremely cold winters throughout 1965-1970 assisted intensification of the water vertical exchange in the Greenland and Norwegian seas. As a result, cols and fresh Greenland Sea Deep Water (GSDW) production was extremely high in the central Greenland Sea while in the southern Norwegian Sea warm and salty waterwater spread downwards. The recent rapid warming in the Greenland Sea Gyre interior from 1980 originates, we argue, from an increase in the Atlantic Water temperature due to the advection of warm waters into the region with the Return Atlantic Current. The negative water temperature and salinity trends are indicative of a warming of that layer. Observation series obtained onboard Ocean Weathership Mike confirmed the existence of layers with advection-driven high oxygen concentrations in intermediate and deep layers. the depth of oxygen maxima and the values of oceanograpgic parameters at this horizon can be regarded as indicators of the convection intensity in the Arctic Domen. A simultaneous rise in NAO index and GSDW temperature points to a link between atmospheric and thermohaline circulation. Weakening in water exchange with the North Atlantic could be the reason for the Polar Water recirculation increase within the Nordic seas.