(4b)
The water vapor equilibrium
fractionation coefficient ( and ) of lake water during evaporation can
be calculated on the basis of the empirical formula of water vapor
interface temperature (in Kelvin, K ) (Horita and Wesolowski,
1994). andare the equilibrium enrichment coefficients ofδ 18O and δ D, respectively, reflecting
the isotopic enrichment effect of water vapor entering the saturated
water vapor layer at the water-gas interface (Craig and Gordon,
1965).andare the kinetic fractionation factor ofδ 18O and δ D, respectively, calculated
from empirical formulas based on atmospheric boundary layer conditions
and humidity conditions. The above calculation can be seen in equation
5.