Improvement of the complementary relationship-based evapotranspiration Models

Abstract

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 averagely 380mm/year less than that by Penman equation(E_pen). To improve this problem, modification coefficient k, defined as k=a*alpha+b, is suggested. Regression coefficients a,b are determined as satisfying k=E_pen/E for evaporation from water and k=1 for evaporation from 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.