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土壤蒸发量的计算是水文学中最棘手的问题之一,器测法、推算法、经验公式法等各有优缺点。本文所介绍的实测土壤水势值法,又为土壤蒸发量的计算提供了一条新的途径。 文中的“通量”系指土壤水分通量,定义为:单位时间内通过某一界面中单位面积的水分量,用q表示,其量纲为[LT~(-1)]。以土壤表层作为界面而言,向上的水分通量就是土壤水分的蒸发强度。所谓“零通量面”,就是水分通量为零的界面,通过此界面的宏观水分流动为零。对于蒸发来说,土壤层中若有零通量面存在,就意味着土壤水分
Calculation of soil evaporation is one of the most difficult problems in hydrology, and its advantages and disadvantages are the instrumental method, the inference method and the empirical formula method. The measured soil water potential method introduced in this paper provides a new way for the calculation of soil evaporation. The term “flux” refers to the flux of soil water, defined as the amount of moisture per unit area passing through an interface per unit of time, expressed in q, and dimensioned as [LT ~ (-1)]. With the soil surface as the interface, the upward flux of water is the evaporation intensity of soil moisture. The so-called “zero flux surface” is the zero flux of water interface, macroscopic moisture flow through this interface is zero. For evaporation, the presence of zero fluxes in the soil layer means soil moisture