On the spatial coherence of the Atlantic Water inflow across the Nordic Seas

International audienceThe co-variability of the Atlantic Water (AW) branches in the Nordic Seas is investigated over the period 1979-2012 using an eddy permitting model. A noticeable circulation change is found in the mid-1990s. Prior to the mid-1990s, the leading mode of variability defines a large scale pattern, with concomitant variations in the Atlantic Water (AW) inflow in the Faroe-Shetland Channel (FSC), the Norwegian Atlantic Slope Current (NwASC), the AW inflow to the Barents Sea and the West Spitsbergen Current (WSC). After the mid-1990s, the co-variability between the NwASC and the AW inflow in both the FSC and the WSC is lost. Consequently, the northern Barents Sea circulation anomaly pattern, which is present throughout the full period, becomes the leading mode of circulation in the northern Nordic Seas after the mid-1990s. The circulation change of the mid-1990s appears to be linked to a weakening of the southwesterly wind anomalies in Norwegian Sea, as the northern center of action of the first mode of sea level pressure (NAO) weakens. Passive tracer experiments suggest that this circulation change may be accompanied by increased heat transfer from the AW current to the interior Nordic Seas. This in turn may have limited the influence of the recently observed AW warming in the Iceland-Scotland Passage on the NwASC downstream