Impact of irrigation methods on LSM spinup and initialization of WRF forecasts

Irrigation represents the largest consumption of freshwater in the United States and has been shown to modify local hydrology and regional climate. This study utilizes both the Land Information System (LIS) and the Weather Research and Forecasting model (WRF) to investigate changes in land-atmosphere interactions resulting from drip, flood, and sprinkler irrigation methods in the Southern Great Plains. Five-year irrigated LIS spin-ups are used to initialize two-day WRF forecasts in relatively dry and wet years (2006 and 2008, respectively). The offline and coupled simulation results show that both LIS spin-ups and LIS-WRF forecasts are sensitive to irrigation and irrigation methods, as exhibited by significant changes to temperature, soil moisture, boundary layer height, and the partitioning of latent and sensible heat fluxes. Dry year impacts are greater than those in the wet year suggesting that the magnitude of these changes is dependent on the existing precipitation regime. Sprinkler and flood irrigation schemes impact the LIS-WRF forecast the most, while drip irrigation has a comparatively small effect.