(7b)
In this equation, F represents the water vapor pressure ratio between the beginning and the end of the water vapor mass. In the research under discussion, F is equal to water pressure ratio between the stations in the track path of the water vapor mass and the Xiying Reservoir, during summer (Wang et al., 2016).
Note that the relevant parameters in the above formula are expressed in decimal form.
3.2 Lake evaporation to inflow ratios
Assuming that the volume of lake water remains stable for a long period of time, the theoretical model of reservoir capacity and stable isotopic equilibrium can be expressed by formula 8 for lakes that are fully mixed with inflow runoff and lake water body.
I L=Q L+E L