Estimation of actual evapotranspiration in 3 river basins in Okayama prefecture - Comparison of Morton method and modified Brutsaert & Stricker method -

In the study, the actual evaporation was estimated in the Asahi River, the Takahashi River, and the Yoshii River basins in Okayama prefecture for four years from January 1999 to December 2002. The Morton method and the modified Brutsaert and Stricker (B & S) method were applied to the three river basins to estimate the actual evapotranspiration and compare the two methods.
As a result, the actual evapotranspiration by the Morton method was all almost equal to that by the Penman’s potential evapotranspiration, and the evapotranspiration was overestimated rather than the actual evapotranspiration. The actual evapotranspiration by the modified B & S method was below the Penman’s potential evapotranspiration throughout the year, and the total annual amount was about 80% of the potential evapotranspiration. In addition, the modified B & S method showed the general tendency that the actual evapotranspiration was lower in urban area than in the hilly and mountainous areas.

研究論文　環境管理工学科