1994 Volume 38 Pages 167-172
The main objective of this study is to develop an methodology for estimating the evaporation from macro-scale hydrologic grid. Macro-scale evaporation formulas, into which the subgrid-scale distribution of related physical equations can be incorporated, were derived from ordinary estimation of formulas of evaporation by means of perturbation method. These formulas are expressed in terms of variance and covariance of the physical quantities. The sensitivity of the sub-grid-scale distributions of surface soil moisture and temperature on the evaporation estimation was examined using bulk method. The major conclusions obtained here are as follows:(1) The estimated values of evaporation is smaller than those without considering subgrid-scale distributions of physical quantities, and (2) Mean and variance of subgrid-scale distribution have the most significant effect on macro-scale evaporation estimation
