Dynamic characteristics and influencing factors of precipitation δ~(18)O, China

摘要

It is the basis of isotope technology application to clarify which factors are related to precipitation isotopes in different regions. China has a vast territory, and there is still no comprehensive and systematic understanding of the spatial distribution pattern and influencing factors of precipitation stable isotopes in China. Based on the known Bowen and Wilkinson model, the latitude and altitude of 117 sites in China were used to simulate delta O-18 value of each site and to generate the high precision spatial distribution map of the precipitation oxygen stable isotope over China. According to the spatial distribution of precipitation delta O-18, the basic effects of isotope variation in different climatic regions were analyzed: latitude effect, elevation effect, temperature effect, precipitation effect, and water vapor source and transportation process. In the eastern monsoon region, the latitude effect of isotope variation is shown, but the difference between the southern region and the northern region is large. The southern region is affected by the water vapor of the subtropical Pacific Ocean and precipitation amount effect to form a high value area of delta O-18, and the northern region is more susceptible to the temperature effect. In the same latitude area, due to the influence of local recycled water vapor and local evaporation, a high-value area of delta O-18 is formed in the inland basin of the northwestern arid region. In the Qinghai-Tibet Plateau, the isotope values affected by the high terrain are generally low. The change of delta O-18 value reflects the extent to which the south and north areas of the Qinghai-Tibet Plateau are affected by the southwest monsoon and local water vapor.