A Numerical Study of the Impact of Wind Farms on Mesoscale Boundaries

Observational and modeling studies have shown wind farms can impact their local microclimate in part due to the removal of momentum from the atmosphere and the creation of turbulence in the boundary layer. High resolution Weather Research and Forecasting Model simulations are used to explore the sensitivity of the propagation of 7 mesoscale boundaries through and in the immediate vicinity of a collection of real world wind farms in west central Texas. Model sensitivity experiments are performed using three wind turbine parameterizations including the default WRF parameterization and two developed for this study. The experimental wind turbine simulations are compared to a control simulation with no turbines present. When compared to the control run, all experimental simulations showed an acceleration of the propagation of the mesoscale boundaries when the boundaries approached the wind farms and a deceleration as the boundaries propagated away from the wind farms. Due to the reduction of winds by the wind farms, boundaries propagating away from the wind farms experience less winds behind the boundaries and propagation speeds are reduced. Boundaries propagating towards wind farms experience less winds ahead of the wind farms and propagation speeds increase. As a consequence, the sensitivity of mesoscale boundary propagation speed to wind turbine type are a function of the non-linear interactions between the wind turbines thrust and power coefficients and the hub-height wind speeds