Submitted to: Decennial National Irrigation Symposium
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2010
Publication Date: 12/5/2010
Citation: Johnson, L., Nemani, R., Melton, F., Michaelis, A., Votava, P., Wang, D., Trout, T.J. 2010. Information Technology Supports Integration of Satellite Imagery with Irrigation Management in California's Central Valley. Decennial National Irrigation Symposium. Proceedings of the 5th National Decennial Irrigation Conference (CDROM). Phoenix, AZ Dec 5-7, 2010. ASABE Paper Number IRR10-9645. 7 pages. Interpretive Summary: A common method to estimate crop water use is through use of reference evapotranspiration (ETo) calculated from meteorological parameters, and a crop coefficient based on crop type and growth stage. California has an excellent weather station network and information management system (CIMIS) that provides growers with ETo information. A challenge with this approach is estimating a crop coefficient (Kc) to convert ETo to crop ET (ETc) for the wide range of crop types, planting configurations, and growing conditions of California's Central Valley. This paper describes a demonstration capability to automatically retrieve and pre-process appropriate satellite imagery, calculate vegetation index values, convert to Fc and hence Kc or basal (primarily, transpiration) crop coefficient (Kcb), and deliver or archive the output map products.
Technical Abstract: Remotely sensed data can potentially be used to develop crop coefficient estimates over large areas and make irrigation scheduling more practical, convenient, and accurate. A demonstration system is being developed under NASA's Terrestrial Observation and Prediction System (TOPS) to automatically retrieve and pre-process appropriate satellite imagery, calculate vegetation index values, convert to estimates of fractional cover and crop coefficients, and deliver or archive the output maps. A user interface will allow convenient retrieval of spatially explicit crop coefficient estimates (e.g., individual fields, irrigation district) for combination with reference evapotranspiration (ETo) and other supporting datasets for derivation of crop ET. The system is intended to eventually support practical irrigation scheduling based on climatic information (as from the California Irrigation Management Information System) for more accurate irrigation water applications that meet crop water requirements.