Evaporation from Lake Biwa

Abstract An experiment has been under way since 1985 to determine the best method to estimate the evaporation from Lake Biwa. A comparison of direct measurements by the eddy correlation method and large evaporation pan method, and the indirect estimation by aerodynamic method and heat balance method was made. As a result, the estimation of evaporation from Lake Biwa was carried out for a long continuous time by the bulk transfer method, based on measurements of surface water temperature, wind velocity, air temperature and humidity at about 6 m above the lake surface, made on a platform 200 m offshore. The annual variation of evaporation was found to be greater in autumn and winter seasons, from September to March, than in spring and summer seasons from April to August.