HR: 1330h
AN: H12B-0997    [PDF]
TI: Investigation of influence of ETc estimation methods to simulate water balance using MIKE SHE
AU: * Islam, M N
EM: mislam@ucdavis.edu
AF: Graduate Student, Dept. of Biological and Agricultural Engineering, University of California, Davis, CA 95616 United States
AU: Wallender, W W
AF: Professor, Dept. of Biological and Agricultural Engineering, University of California, Davis, CA 95616 United States
AU: Wicks, S
AF: Graduate Student, Dept. of Agriculture and Resources Economics, University of California, Davis, CA 95616 United States
AU: Howitt, R
AF: Professor, Dept. of Agriculture and Resources Economics, University of California, Davis, CA 95616 United States
AU: Mitchell, J P
AF: Extension Specialist, Dept. of Vegetable Crops, University of California, Davis, CA 95616 United States
AB: Potential evapotranspiration, ETc plays an important role in simulating soil water content, drainage and water table elevation. Among many different methods to estimate ETc, crop coefficient approach (ETc = ET0*Kc), the effect of the various weather conditions are incorporated into reference evapotranspiration, ET0 and the crop characteristics into the crop coefficient Kc, has been adopted in this study. However, Kc can be obtained from either single or dual crop coefficient methods according to FAO guidelines. In single crop coefficient approach, the effect of both crop transpiration and soil evaporation are integrated into a single crop coefficient to obtain crop ETc. On the other hand, crop coefficient can be improved for estimating the effects of daily evaporation from wet soil on Kc and by splitting the coefficient into evaporation and transpiration has been demonstrated in many studies. This study investigates how ETc obtained from these two methods influences the simulation of water content using MIKESHE, a physically based hydrologic model, keeping all other parameter and dynamic variables constant. The results indicate that little improvement in terms of RMSE can be achieved using the dual crop coefficient method.
DE: 1818 Evapotranspiration
DE: 1829 Groundwater hydrology
DE: 1836 Hydrologic budget (1655)
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting