Comparison of the atmospheric forcing and oceanographic responses between the Labrador Sea and the Norwegian and Barents seas

A comparison of the mean conditions and variability in the climate and physical oceanographic characteristics between the Labrador Sea and surrounding shelves and the Norwegian and Barents seas is presented. The two regions are strongly advective systems being influenced by both cold, low saline flows from the Arctic and warm, high saline flows from the Atlantic. However, Arctic flows are more dominant in the Labrador Sea region, especially on the shelves, while Atlantic flows dominate in the Norwegian and a large part of the Barents Seas. In spite of this, the study reveals a general latitudinal dependence for several climate and oceanographic variables, including air temperatures, eastward winds, heat fluxes, and seasonal sea surface temperature range, within each of the two regions but with regional varying rates of change with latitude. We also confirm the previously reported out-of-phase relationships on interannual to decadal time scales of air and sea temperatures and sea-ice conditions between the Labrador Sea and the Norwegian and Barents seas regions from the 1950s until the mid-1990s. This is owing to their opposite response to the variability in the North Atlantic Oscillation (NAO). However, from the mid-1990s, air and sea temperatures in both regions generally have been in phase, showing strong warming and reduced ice coverage. The cause of this change is related to changes in the spatial structure of the atmospheric pressure patterns, resulting in a general reduction in the importance of NAO forcing over the North Atlantic.