抄録
The present paper describes a new method to precisely calculate hourly evaporation flux under quasi-unsteady wind velocity using the wind tunnel that can supply a set of high/low speed winds by turns for every set-up period. Soil columns was used for the evaporation experiment and Chao soil and Toyoura standard sand were used for the experiment. The difference in the hourly evaporation flux, Evh, became no less than 12-18% by changing the combination of the high/low speed winds, regardless of the kind of soil, although the average wind velocity, Vwm, was the same for all the wind-velocity combinations. This fact is attributed to the nonlinearity of the relation between the evaporation coefficient, αv, and wind velocity. It is found that Evh calculated using αv for the high and low wind velocities is more accurate than that calculated using αv for Vwm.
