A model-based comparison of extreme winds in the Arctic and around Greenland

摘要

This paper compares extreme value statistics of daily maximum 10 m wind speed in winter simulated by the regional climate model COSMO-CLM at a horizontal resolution of 15 km (C15) with the reanalyses ERA-Interim and Arctic System re-analysis (ASR version 1 and 2) and with a satellite data set (CCMPv2). Our C15 simulation (1979/1980-2015/2016, November-April) is thereby the longest high-resolution simulation available for the Arctic. The results show that the extreme wind speeds tend to increase over the ocean with increasing the horizontal model resolution. A horizontal resolution of = 15 km is required to sufficiently capture all extreme wind characteristics, in particular for the tip jets and barrier winds over the Irminger Sea and in the Denmark Strait, and for the low-level jets in the Nares Strait. Of almost equal importance are physical parameterizations of surface fluxes and of turbulence. Capturing extreme wind characteristics has a direct effect on climate relevant air-ice-ocean interactions, such as triggering open-ocean deep convection, polynya dynamics, or on the sea ice and freshwater balance of the Arctic.