Simulations of Stable Isotopic Variations in Precipitation and Comparison with Measured Values in Yunnan Province,China

Using the MUGCM simulations,the variation features of stable isotopes in precipitation,amount effect and relationship between δD and δ18O,on the diurnal,monthly and yearly time scales in Yunnan Province,China,are analyzed.There is significant amount effect for the isotopes in precipitation,whether on the diurnal time scale or on the monthly or the yearly time scales.Compared with the measured values,the simulated δ18O in precipitation shows the stronger correlation with precipitation.For the single station,the local meteoric water line(LMWL) is simulated well at Mengzi and Tengchong,however at Simao and Kunming,the simulated results do not reproduce truly the measured relationship between δD and δ18O in precipitation with the higher LMWL slopes,which implies that the model may overestimate the depletion of the HDO over such a particular areas like Yunnan.