Experimental Study on Evaporation Pan Isotopic Variations

Lake participates in water cycle through inflow and outflow of surface water and groundwater, precipitation and evaporation. Stable isotope technique is a very useful tool for studying variation of lake water. This paper briefly introduced the isotopic theory of lake, and studied the isotopic variation of atmospheric water vapor delta_A through indoor and outdoor evaporation pan experiments. The experimental results showed that delta_A values estimated from isotopic mass balance method were suitable to study the short-term isotopic variation of lake at time interval of six days; the slope of pan evaporation line of outdoor experiment was lower than that of indoor experiment due to kinetic fractionation factor of outdoor experiment being higher than that of indoor experiment.