利用稳定同位素估算乌梁素海蒸发量

Based on the water quantity balance and stable isotope mass balance principle, a lake fractionation model is established. The mean evaporation of Wuliangsuhai Lake is calculated by using the lake fractionation model, and some factors effecting the lake evaporation value such as air humidity, temperature are discussed. As the results show, the isotope fractionation at gas-liquid interface during evaporation is the foundation of isotope value changes above lake surface. At the same time, water molecules which enrich heavy isotope escape from liquid phase earlier than that of light ones because of evaporation fractionation. With other factors unchanged, the greater the proportion of evaporation, the bigger value of δ18O of the lake water is. Evaporation of Wuliangsuhai Lake accounts for 39.43% of the annual recharge rate, and the relative error between calculated and measured values is 4.62%. The research shows that he greater air humidity is, the smaller lake evaporation is; the higher temperature is, the greater lake evaporation is.