Extreme indices and return levels of daily maximum 10m wind speed in the Arctic and around Greenland

A polar-adjusted version of the regional climate model COSMO-CLM was used at a horizontal resolution of about 15km (0.125°; C15) to simulate and analyse extreme 10m wind speeds from 1979-2016 in winter (Nov to Apr) in the Arctic and around Greenland. Based on daily maximum 10m wind speeds, extreme indices (95% percentiles, average strong gale and hurricane days per winter) and return levels up to the 20year return period are calculated and compared with state-of-the-art reanalysis data sets (ERA-Interim, ASR version 1 and 2) and with the satellite product CCMP version 2. The return levels were calculated by the 'peaks-over-threshold' (POT) method which fits a General Pareto distribution (GPD) to extreme values exceeding a specified high threshold (for this study the local 95% and 99% percentiles). The model comparison was based on the overlapping winter period 2000-2012 (Nov to Apr). Before the analysis all data sets were interpolated onto the rotated model grid of C15 (450x350 grid boxes, with the rotated pole located at 100°W and 0°N).