A coupled groundwater-atmospheric model for wind energy forecasting

Complete models of the hydrologic cycle have gained recent attention as research has shown interdependence between the coupled land and energy balance of the subsurface, land surface and lower-atmosphere. We have developed a new model, PF.WRF, which is the combination of the Weather Research and Forecasting (WRF) atmospheric model and ParFlow (PF) a parallel hydrology model that fully integrates three-dimensional, variably-saturated subsurface flow with overland flow. These models are coupled via the Noah land surface model (LSM). We demonstrate the improvement in important physical processes afforded by the coupled model using a number of semi-idealized simulations over the Little Washita watershed in the Southern Great Plains of the US. To quantify the significance of subsurface physics, compared with other physical processes calculated in WRF, we carry out these simulations with two different surface spin-ups and three different microphysics parameterizations in WRF. These simulations illustrate enhancements to coupled model physics for wind energy forecasting. Because soil moisture is expected to impact boundary-layer winds, we demonstrate the applicability of the model to wind-energy applications by using PF.WRF and WRF simulations to provide estimates of wind and wind-shear that are useful indicators of wind-power output.