VARIABILITY OF CROP COEFFICIENTS IN SPACE AND TIME - EXAMPLES FROM CALIFORNIA

摘要

Crop coefficients are calculated for almonds, citrus, and grapes in California based on arncombination of remote sensing of actual crop evapotranspiration from the Surface EnergyrnBalance Algorithm for Land (SEBAL~?) and ground-based reference evapotranspiration from thernCalifornia Irrigation Management Information System (CIMIS). Crop coefficients are calculatedrnat the field scale, and the apparent variability in crop coefficients among fields and over time isrnexamined. Crop coefficients derived from remote sensing are compared to published values usedrnwith reference evapotranspiration for estimation of crop water use. The opportunity to refinerncrop coefficients for irrigation management and water resources planning through improvedrnunderstanding of the variability in crop water use via remotely sensed crop evapotranspirationrnestimates is discussed.