Winds in the South Baltic Sea: Working towards a Wind Atlas

The South Baltic Sea is surrounded by several countries that already have or plan to have offshore wind farms. The countries include Denmark, Estonia, Germany, Latvia, Lithuania, Poland and Sweden. Winds offshore are being mapped in a joint effort using several sources of information as well as modeling of the atmospheric flow. The bservations from local meteorological masts are collected and analyzed. The data series are not very long, around 3 years. Satellite remote sensing observations from both scatterometer and synthetic aperture radar (SAR) are collected and analyzed. It is the gridded ocean wind vector product from QuikSCAT from Remote Sensing Systems (RSS) used. This data series span 10 years, from 1999 to 2009. The SAR data are from the European Space Agency (ESA) satellite Envisat with the Advanced SAR (ASAR) on-board. This data series spans from 2002 to present. It should be noted that QuikSCAT covers the entire South Baltic Sea twice per day whereas Envisat ASAR only cover with ~10 wind maps per month. The wind statistics from SAR is thus based on far fewer observations than QuikSCAT. The advantage of SAR ocean winds is the high spatial resolution around 1 km by 1 km grid. The atmospheric modeling is done using Weather Research and Forecasting (WRF) mesoscale model. It is run in a forecasting mode for around 3 years and the results are weighted by long-term statistics from NCEP re-analysis. The presentation will discuss the advantages and limitations of the various data sources and also the uncertainty on the model results. The work is part of the EU-Norsewind and EU-South Baltic OFFER projects.