Using SST for imporved mesoscale modelling of the coastal zone

Many offshore wind farms are located and planned in the near-coastal areas, where the winds are higher and connection to the grid is easier. Existing wind measurements in near-shore and offshore areas are sparse and scarce, therefore simulations from state-of-the-art meso-scale models are used for wind resource predictions.

In coastal and near-shore areas, models are inaccurate and uncertain, mainly because of numerical approximations, which do not resolve the large changes in local topographic features and atmospheric stability well (Floors 2013). In coastal and near-shore areas, such models are rather inaccurate and uncertain, primarily due to their numerical approximations, which do not resolve the large changes in local topographic features and atmospheric stability well.

The accuracy of modelled wind resource predictions can be improved by using local wind measurements to calibrate the models. The RUNE project aimed at Reducing Uncertainty of Near-shore wind resource Estimates and investigated cost-effective measurement solutions for improving the wind resource modelling of coastal areas.

During the RUNE project, the wind over a coastal area was measured by land-based lidar systems, an offshore lidar buoy and satellite radar remote sensing (SAR and scatterometers) while simulations from the Weather Research & Forecasting (WRF) mesoscale model were performed. The purpose of the analysis is to evaluate the uncertainty of the modelled wind in the coastal zone and further improve it.

The high-resolution daily SST analysis product from the Danish Meteorological Institute (DMI) (Høyer and Karagali, 2016), specifically developed for the North Sea and Baltic Sea region was introduced as a boundary condition to WRF. In addition, to improve the physical description of the domain, the elevation, topography and land use, the CORINE land cover with a spatial resolution of 100~m to 250~m and the SRTM elevation database were used as boundary conditions.

This study provides an overview of the measurement campaign and the lidar systems in Section 2 and the description of the model set-up in section 3. Some preliminary results regarding the sensitivity of the model to different options for the SST, land use, resolution and PBL scheme are presented in Section 4.1 while comparisons with the lidar measurements are presented in Section 4.2.

Finally, the conclusions are available in Section 5.