Evaporation from Deep Lakes in Japan

Abstract

A method of estimating evaporation from a relatively deep lakes using the climatological data of wind velocity, air temperature and vapor pressure over lake is developed. Merit of this method is that these data are easy to infer from those at the meteorological stations in the vicinity of the lake, even if there are no direct observations over the lake. The method consists of solving the equation of heat conduction in the lake together with the heat balance equation at the water surface taking into account some results of the turbulent transfer theory, and thus obtaining evaporation and water temperature simultaneously; the surface value of the latter being deeply related to evaporation. Estimation of these values by this method is made on representative lakes in Japan and the estimated results are compared with the observed ones. In addition, some climatologicalfeatures of lake evaporation are pointed out with the help of the estimated values.