Atmospheric forcing and oceanic response during strong wind events around southeastern Greenland as modeled over 20 winters in the Regional Arctic System Model (RASM)

Alice K. DuVivier1, 2, John J. Cassano1, 2, Anthony Craig3, Wiesalaw Maslowski3, Robert Osinski3, 4, Andrew Roberts3

Abstract
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 wind regimes present during twenty winters (1990-2010, NDJFM) in the fully coupled Regional Arctic System Model (RASM). For all wind patterns the ocean loses buoyancy, primarily through the turbulent sensible and latent heat flux thermal terms; haline contributions to buoyancy loss were found to be insignificant compared to the thermal contributions. Patterns with westerly winds at Cape Farewell 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. Patterns with easterly flow at Cape Farewell have large buoyancy loss along the sea ice edge in the Denmark Strait and a secondary, local maximum immediately west of Cape Farewell. The ocean mixed layer is anomalously deep for wind patterns that have northerly flow with either easterly or westerly winds at Cape Farewell; mixed layer deepening is positively correlated to the frequency of those patterns and of greater magnitude for longer duration events.