Advection-Aridity(AA) model can calculate actual evapotranspiration by using only meteorological data. However, comparing the model with Penman equation showed that AA model doesn’t properly evaluate evapotranspiration from urban moisture area. In urban area, Actual evaporation from water calculated by AA model(E) are much less than that by Penman equation(Epo). Multiple regression analysis using estimation results indicates that the difference between the models is due to the difference of the sensitivity to vapor pressure deficit between the models. To improve this problem, modification coefficient k, defined as k=a･albedo+b, is suggested. Regression coefficients a, b are determined as satisfying k=Epo/E for water and k=1 for urban surface. By using this coefficient k, evaporation from water is nearly equal to value estimated by Penman equation, while evaporation from urban surface is changeless
