Evaluation of Irrigation Physics in a Land Surface Modeling Framework and Impacts on Coupled Prediction

Abstract:

Soil moisture controls water and energy fluxes from the land surface to the planetary boundary layer and determines plant stress and productivity. Therefore, developing a realistic representation of irrigation is critical to understanding land-atmosphere interactions in agricultural areas. Irrigation parameterizations are becoming more common in land surface models and are growing in sophistication, but there is difficulty in assessing the realism of these schemes, due to limited observations (e.g., soil moisture, evapotranspiration, etc.) and unknown timing of human practices and real world application. This study addresses some of these issues by using a high-resolution soil moisture observational product and detailed field-scale irrigation data to evaluate the following: 1) the realism of irrigation amounts and timing simulated by the sprinkler irrigation algorithm in NASA’s Land Information System (LIS), 2) the irrigation water’s impact on soil moisture and fluxes, and 3) the effects of realistic irrigation-induced soil moisture changes on land-atmosphere energy exchanges as simulated by the NASA-Unified WRF (NU-WRF) coupled to LIS.