The overall purpose of the project is to assess the potential for NASA satellite data (MODIS and Landsat) and Land Information System (LIS) land surface model output products to improve performance of U.S. Bureau of Reclamation's AWARDS ET (evapotranspiration) Toolbox decision support tool. The ET Toolbox is used in forecasting water demands within the RiverWare river operations system in the Middle Rio Grande (MRG). The purpose of the DST is for better monitoring and management for irrigation farmers, reservoir managers, meeting endangered species regulations, and other water management needs. Crop irrigation is the largest surface water use in the Basin, accounting for up to 90 percent of surface water withdrawals. Estimates of water demands is uncertain due to spatial variability of evapotranspiration (ET) and changes in ET from year to year.

The primary project emphasis is with 1) water availability including ET through the NASA Land Information System (LIS) software environment and the land surface models, and 2) NASA satellite products derived through the METRIC-ET. LIS water availability estimates and METRIC ET are compared with results from the AWARDS ET Toolbox and independent ground surface observations. For this study, LIS is set up and calibrated for comparisons with the current ET Toolbox configuration and datasets. A variety of satellite datasets are used to help parameterize and drive the models, including data from NASA MODIS data (e.g., land cover and LAI). The basis for the satellite ET products has been MODIS and Landsat imagery processed by the University of Idaho (UI) METRIC (Mapping ET at High Resolution with Internalized Calibration) routine. Direct integration of primarily MODIS and Landsat data into ET ToolBox will circumvent the costly and quickly out-of-date current crop classification and land-use type inputs to ET Toolbox estimation.

Preliminary results comparing NASA LIS Noah and Catchment land surface models with surface in situ heat flux measurements has demonstrated a capability to model riparian and agriculture evapotranspiration along the riparian corridor. The LIS modeling framework will permit Reclamation to forecast (1-7 days) water loss demands. Evapotranspiration derived from Landsat images have been used to validate MODIS based ET maps and to assist with development of automated calibration of MODIS based METRIC. METRIC ET images, because of their surface energy balance basis, contain accurate information on ET over wide ranges of vegetation type and growth stage. METRIC ET may also be used to provide updated “crop coefficient”, Kc (crop coefficient and is the ratio of actual ET from a specific pixel or area to weather-based reference ET) as used by the AWARDS/ET Toolbox. The ET Toolbox crop coefficients are derived under near optimal conditions and are largely outdated. Future plans are to further intercompare LIS ET modeling, ET Toolbox and METRIC ET results.