NORSEWIND – Mesoscale model derived Wind Atlases for the Irish Sea, the North Sea and the Baltic Sea

As a part of the EU Framework 7 R&D Program NORSEWInD, Wind Atlases for the Irish Sea, the North Sea and the Baltic Sea have been developed and made public available. In the present study the development of the offshore Wind Atlases is focused on the use of mesoscale model data since the access to measurements and satellite data have been limited. Mesoscale model runs were carried out for focus areas with high spatial model resolution (2 km) and the entire Wind Atlas domain with coarser resolution (6 km). The annual average wind speed data have been long-term adjusted. Through the NORSEWInD project we have experienced that mesoscale models are efficient and accurate tools for generating offshore Wind Atlases. Long-term annual average wind speeds are estimated to have a random uncertainty of ±4.2 % and a bias of -1.3 % which is lower than what is experienced onshore. For the Weibull k-parameter we estimate a random uncertainty of ±4.0 % and a bias of -6.4 % which is higher than for the average annual wind speed. It is emphasized that the amount of validation data is small and considerable spatial variability of the uncertainty may be expected. For example, near coastal zones model errors could be expected to be larger than far offshore.