Earth Observations and Land Surface Models to Support Agricultural Water Resources Management (Centennial)

The objective of this work is to enhance the use of Earth observations, hydrological and land surface models to assess the exchange of water between the soil, the vegetation and the atmosphere in support of agricultural water resources management and irrigation scheduling. The project outcomes provide timely and relevant assessments of agricultural water use and available water supply from local to regional scales, with the capability to predict the impact of different climate and water resources management scenarios. The approach is based on the use of ground and satellite-based observations to calibrate models describing surface water exchange processes at different scales (from the field to the watershed), and short-term climate forecast to assess the evolution of water availability for the next week and the crop season. We focused on a diverse set of pilot sites in Argentina, New Zealand, Tanzania and the United States that are representative of a range of agricultural systems, water issues and climate impacts. Over corn fields in Iowa, the assimilation of land surface temperature products from Landsat-8 was used to simulate continuous time series of hourly surface evapotranspiration with root mean square errors less than 60 W m^-2 during the crop season. In Tanzania, precipitation estimates from IMERG were used to describe the spatial variability of rainfall within the Wami basin and to significantly improve the simulated streamflow compared to simulations based on information from sparse rain gauge networks.

This work is funded by the NASA Applied Sciences Water Resources Program and is part of the NASA Harvest Consortium. This presentation will provide an overview of the project objective and methods used to assess water resources.