Biological Engineering Commons^™

A Modified Surface Energy Balance For Modeling Evapotranspiration And Canopy Resistance, Luis O. Lagos

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

A modified surface energy balance (SEB) model based on the Shuttleworth-Wallace and Choudhury-Monteith methods was developed to estimate evaporation from soil covered by crop residue, and transpiration from crop canopies. The model describes the energy balance and flux resistances for partially-vegetated and residue-covered surfaces. Physical and biochemical energy storage terms and lateral fluxes are neglected in the model. Net radiation is one of the inputs in the SEB model and provides the energy needed for soil evaporation, crop transpiration and heat transfer through the canopy, soil/residue surfaces and the atmosphere.

A sensitivity analysis of the SEB model parameters showed that …

Variability Analyses Of Alfalfa-Reference To Grass-Reference Evapotranspiration Ratios In Growing And Dormant Seasons, Suat Irmak, Ayse Kilic, T. A. Howell, Derrel Martin, J. O. Payero, K. S. Copeland

Biological Systems Engineering: Papers and Publications

Alfalfa-reference evapotranspiration (ET_r) values sometimes need to be converted to grass-reference ET (ET_o), or vice versa, to enable crop coefficients developed for one reference surface to be used with the other. However, guidelines to make these conversions are lacking. The objectives of this study were to: (1) develop ET_r to ET_o ratios (K_r values) for different climatic regions for the growing season and nongrowing (dormant) seasons; and (2) determine the seasonal behavior of K_r values between the locations and in the same location for different seasons. Monthly average K_r values …