Winter Oceanic Response During Strong Wind Events Around Southeastern Greenland in the Regional Arctic System Model (RASM) for 1990-2010

Strong, mesoscale tip jets and barrier winds that occur along the southeast Greenland coast have the potential for impacting deep convection in the Irminger Sea. The self-organizing map (SOM) training algorithm was used to identify 12 wind patterns that represent the range of winter (NDJFM) wind regimes identified in the fully coupled Regional Arctic System Model (RASM) during 1990-2010. For all wind patterns the ocean loses buoyancy, primarily through the turbulent sensible and latent heat flux thermal terms; haline contributions to buoyancy change were found to be insignificant compared to the thermal contributions. Patterns with westerly winds at the Cape Farewell area had the largest buoyancy loss over the Irminger and Labrador Seas due to large turbulent fluxes from strong winds and the advection of anomalously cold, dry air over the warmer ocean. Similar to observations, RASM simulated typical ocean mixed layer depths of ~400 m throughout the Irminger Basin with individual years experiencing mixed layer depths of 800 m or greater. The ocean mixed layer deepens over most of the Irminger Sea following wind events with northerly flow, and the deepening is greater for patterns of longer duration. Seasonal deepest mixed layer depth is strongly and positively correlated to the frequency of westerly tip jets with northerly flow.