Modeling Atlantic Water pathways and variability in the Norwegian, Greenland and Barents Seas in the past 60 years

The accelerating retreat of sea ice cover in the Arctic Ocean requires understanding of all of its forcings, both by the atmosphere and the ocean. One of the important sources of heat in the eastern Arctic is associated with warm Atlantic Water (AW) advected from the North Atlantic, across the Barents Sea and through Fram Strait into the Arctic Ocean. A version of the Regional Arctic System Model (RASM) forced with realistic atmospheric data from the Common Ocean Reference Experiment version 2 (CORE2) 1948-2009 reanalysis shows an increased northward volume transport across Fram Strait in the 2000s. One of the questions we attempt to address with the RASM model is if this is a unique occurrence or a repeating event in the past 60 years. RASM results suggest that events with even stronger West Spitsbergen Currents (WSC) have happened in the past, for instance in the early 1990s. The unique situation in the first decade of the 21st century was that a substantial amount of volume and heat carried by the WSC entered the Arctic Ocean directly, whereas in the past most Atlantic Water recirculated within the Greenland Sea and Fram Strait. Finally, we also analyze results related to AW entering Barents Sea Opening (BSO), which show significant correlations between the strength of the WSC and heat and volume fluxes across BSO.