干旱区生态环境知识资源中心

A comparison of output from two models estimating spatially distributed surface energy fluxes from remotely sensed imagery is analyzed. A major difference between the two models is whether the soil and vegetation components are treated separately (two-source) or lumped (one-source) in the parameterization of radiative and turbulent exchanges. Comparisons are performed using data from two large-scale field experiments covering sub-humid grassland (Southern Great Plains '97) and semi-arid rangeland (Monsoon '90) having very different landscape properties. In general, there was reasonable agreement between flux output from both models versus a handful of flux tower observations. However, spatial intercomparisons yielded relatively large discrepancies (-100 W/m(2)) in the turbulent heat fluxes that appeared to be related to land cover. Sensitivity to a key input for each model indicates that the uncertainty in specifying this input hits a greater impact on one-source model output for all land cover types.