Impact of wind farms on surface and air temperatures

Socioeconomic forcings and policy decision are causing an increase of wind farm installations. If spatially large enough, wind farms become an important element of a regional climate system due to their influence on mean and turbulent kinetic energy. A wind turbine converts the wind's mean kinetic energy into electricity and induces turbulent kinetic energy downwind of the turbine, which in turn affects the vertical distribution of atmospheric variables such as temperature, dew point, wind speed and direction amongst others. A recent observational study using satellite data has shown significant change in local surface temperatures. Previous numerical modeling studies have shown a warming of the surface and reduced sensible heat flux but have been limited to idealized hypothetical wind farm scenarios. In this work we possible investigate the impacts of realistic wind farms identified using FAA data. We employ the Weather Research and Forecast (WRF) model as a regional climate model with 1km spatial resolution over a region in West Central Texas where four of the world's largest wind farms containing 2,359 individual turbines are located. The WRF model is compared to satellite and station observations. The high spatial resolution provided by WRF is used to analyze the transport of aforementioned atmospheric variables in and downwind of the wind farms. Results show that turbulent mixing induced by wind turbines causes an increase in surface temperatures while the boundary layer is stable. In a well-mixed or unstable boundary layer, surface temperatures signals are mixed, although the affect is much less pronounced.