干旱区平原水库模拟蒸发量试验研究

干旱区平原水库水面蒸发是平原水库水量损失的重要组成部分,由于水库面积大,采用常规蒸发皿测定的蒸发量与水库实际蒸发量特征不相符。为了准确模拟干旱区平原水库蒸发量,开展了模拟水库的小面积水域蒸发试验,通过水位测针测量蒸发池的蒸发量,并与蒸发皿蒸发量进行比较。试验结果表明,在实际蒸发量中,蒸发池的蒸发量波动较大,蒸发皿蒸发速率比水面蒸发速率高9.1%。蒸发皿蒸发量与水面蒸发量的比值呈现先下降后上升的趋势;蒸发池水面蒸发量主要受到温度、净辐射、风速、饱和水汽压差影响;蒸发皿水体容量小,与蒸发池相比水体热容量较小,因此与大气交换更加快速,受净辐射和气温日较差影响较大。

Experimental research of evaporation simulation of reservoirs in arid plain area

The surface evaporation of reservoirs in arid plain contributes great to the water losses of the reservoir. The meas-ured evaporation by using the conventional evaporation pan is not in line with the actual evaporation characteristics of the reser-voirs due to large water surface. Therefore, a small area evaporation test was conducted. The evaporation of the pond was meas-ured through water level marking pin, and was compared with the pan evaporation. The results show that in actual evaporation, the evaporation of the pond fluctuates;the evaporation pan has a 9. 1% quicker evaporation speed than the surface evaporation, and the ratio of pan evaporation to the water surface evaporation increases at first and drops then;evaporation in pond is mainly affected by temperature, net radiation, wind speed and saturation vapor pressure difference. Since the water capacity of evapora-tion pan is small, the water heat capacity is smaller compared with the evaporation pond, the heat exchanges with the atmosphere more quickly, so it is influenced by the net radiation and diurnal temperature range greatly.