Comparing satellite SAR and wind farm wake models

C B Hasager,A Di Bella,R Husson,A Palomares,P Vincent,J Badger,A Peña,P Volker,E Cantero,P M F Correia,M Badger,A Mouche

doi:10.1088/1742-6596/625/1/012035

Abstract

The aim of the paper is to present offshore wind farm wake observed from satellite Synthetic Aperture Radar (SAR) wind fields from RADARSAT-1/-2 and Envisat and to compare these wakes qualitatively to wind farm wake model results. From some satellite SAR wind maps very long wakes are observed. These extend several tens of kilometres downwind e.g. 70 km. Other SAR wind maps show near-field fine scale details of wake behind rows of turbines. The satellite SAR wind farm wake cases are modelled by different wind farm wake models including the PARK microscale model, the Weather Research and Forecasting (WRF) model in high resolution and WRF with coupled microscale parametrization.

Highlights

The wake of the offshore wind farms are observed from Synthetic Aperture Radar (SAR) satellite data [1, 2, 3]
The aim of the paper is to present offshore wind farm wake observed from satellite Synthetic Aperture Radar (SAR) wind fields from RADARSAT-1/-2 and Envisat and to compare these wakes qualitatively to wind farm wake model results
The simulations performed by the micro- and meso-scale models tried to reproduce the real effects of several wind farms on the downstream wind observed through SAR satellite images

Summary

Introduction

The wake of the offshore wind farms are observed from Synthetic Aperture Radar (SAR) satellite data [1, 2, 3]. The basic measurement principle consists of emitted microwave radiation at C-band (wavelength around 5 cm) that is backscattered from the natural surface and objects . Ocean swell waves, tidal flow over shallow water areas and sea ice produce imprint. The ocean objects observed are ships, wind turbines, oil/gas platforms and other man-made structures at sea. The roughness of the sea appears darker for lower wind speed and brighter for higher wind speed because the backscatter from capillary and short-gravity waves at the surface of the ocean relates to surface wind speed. Small white dots seen in SAR images over the ocean are most likely ships or wind turbines. The backscatter is very high for hard targets [4]

Objectives

Conclusion