Abstract
The annual and monthly evapotranspiration is estimated using water budget method in the Kiryu and Kawamukai Experimental Catchments located in Shiga Prefecture to the south of Lake Biwa, in hilly mountains consisting of weathered granite. The annual evapotranspiration is estimated at 720_??_760mm by annual water budget in this area. The seasonal variations of evapotranspiration estimated in Kiryu, in Kawamukai and in Kamigamo located in Kyoto City are similar to one another. The monthly evaporation of rainfall interception, calculated by the model reported in the previous paper, varies with rainfall amount, but the range of variation is smaller than the other items. The transpiration is estimated from the evapotranspiration and evaporation of rainfall interception, assuming that the evaporation from the soil surface or forest floor in crown-closed forest is negligible. The annual transpiration in Kiryu (average 1972_??_1976) is 396.8mm, 53 percent of the gross evapotranspiration. The monthly transpiration is 0_??_13mm in winter and 50_??_65mm in summer. Transpiration is a major component of evapotranspiration from May to November, and the evaporation of rainfall interception predominates in the other months in the Kiryu Catchment.
