Comparison of wintertime mesoscale winds over the ocean around southeastern Greenland in WRF and ERA-Interim

Abstract

Strong, mesoscale tip jets and barrier winds that occur over the ocean near southern Greenland have the potential for impacting deep convection in the ocean. The self-organizing map (SOM) training algorithm was used to identify and classify the range of 10 m wind patterns present during ten winters (1997–2007, NDJFM) in the ECMWF interim reanalysis (ERA-I) and from a regional simulation using the weather research and forecasting (WRF) model at 50 km into a SOM. The SOM is used to identify differences in the manifestation of westerly tip jets, easterly tip jets, and barrier flow. The North Atlantic Oscillation (NAO) index is well correlated with the type of tip jet present at Cape Farewell, but the NAO was not well correlated with the absence or presence of barrier flow. WRF simulated patterns with strong barrier-parallel flow more frequently than ERA-I, and WRF also had faster coastal winds than ERA-I during all types of strong wind events. The difference in coastal winds is likely related to model resolution and the resulting ability of each model to simulate strong mesoscale winds that are driven by Greenland’s steep terrain.