Northeast Atlantic and North Sea storminess as simulated by a regional climate model 1958-2001 and comparison with observations.

Abstract

An analysis of the storm climate of the Northeast Atlantic and the North Sea as simulated by a regional climate model for the past 44 years is presented. The model simulates the period 1958-2001 driven by the National Center for Environmental Prediction's (NCEP's) weather re-analysis. Comparison with observations shows that the model is capable of reproducing impact related storm indices such as the number of severe and moderate storms per year or the total number of storms and upper intra-annual percentiles of near-surface wind speed. The indices describe both, the year-to-year variability of the frequency as well as changes in the average intensity of storm events. Analysis of these indices reveals that the average number of storms per year has increased near the exit of the North Atlantic Storm track and over the Southern North Sea since the beginning of the simulation period (1958), but the increase has later leveled off over the North Sea and the average number of storms per year is even decreasing over the Northeast Atlantic since about 1990-1995. The frequency of the most severe storms follows a similar pattern over the Northeast North Atlantic while there occurred too few severe storms in other areas of the model domain preventing a statistical analysis for these areas.