Improved evapotranspiration estimates to aid water management practices in the Rio Grande River Basin

To improve the efficiency of water management and irrigation scheduling in the Rio Grande River basin, the U.S. Bureau of Reclamation helped create the Agricultural Water Resources Decision Support (AWARDS) system. Through its Evapotranspiration (ET) Toolbox interface, the AWARDS system provides guidance to local farmers on when and where to deliver water to the crops. The ET Toolbox is based on water usage estimates (evapotranspiration and open water evaporation) on a grid cell basis (4 km/spl times/4 km). Currently, crop water use estimates are determined using a modified-Penman ET approach. To improve upon this parameterization, we use the Community Land Model (CLM2.0) within the LDAS system downscaled to a 1 km grid cell resolution. Our work aims to improve evapotranspiration and soil moisture estimates in the Rio Grande River basin through the improvement of the CLM2.0 parameterization of surface processes. We specifically intend to assimilate up to four land surface temperature (LST) observations per day from the Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) instruments, at 1 km resolution, into the CLM2.0 land surface model. To verify the performance of the assimilation approach we deploy flux towers at two different sites. We focus our ground data collection on riparian and agricultural areas. Ultimately, our results should improve the daily forecasts of vegetation water requirements and, when integrated into operational decision support tools, aid water resource managers in making flood and drought assessments and predictions.