Representativity of near surface wind measurements from coastal stations at the German Bight

Abstract

The public interest in wind climate is increasing because of the continuously growing wind energy sector on the one hand and the large effects of recent extraordinary events in the storm climate like the severe storm Kyrill in 2007 on the other. Therefore, there is a high demand for high quality wind data for investigations into the regional wind climate. Even though the sensitivity of the measurand wind and the related difficulties in obtaining homogenous series of measurements are well-known (Wieringa, 1996; WMO, 2008), near surface wind measurements are nevertheless often used as representatives for the regional wind climate. In the offshore wind energy sector it is a common approach to extrapolate data from coastal stations for estimating the wind conditions at prospective offshore sites. To evaluate the reliability of such coastal wind data series, measurements from five near coastal weather stations over the same 53 year period were collected. Comparisons to observations of a different measuring net were conducted to investigate the influence of changes in the sampling frequency. Intercomparisons between the yearly means and 99th percentiles of the five stations show a low similarity. This emphasizes that wind speed measurements are strongly influenced by the particular environment. To focus on the effect of station relocations, a case study for Helgoland, the data of which are often used as a proxy for the regional wind climate in the German Bight, is conducted including a valuation of the effect of the station relocation on wind power statistics.