A model-based determination of spatial variation of precipitation δ18O over China

Many works show the dependence of precipitation δ18O on altitude and latitude as a result of air temperature change. The assumption that these quantitative relations can hold across a large geographical region can be used to give a rough estimation of local precipitation δ18O where there is on direct observation of precipitation δ18O. Although there truly exists uncertainty in the estimation, an effect was made in this paper to establish the precipitation δ18O pattern over the whole China. Based on regional topography and the δ18O of meteoric precipitation, this paper established a quantitative relationship between δ18O in precipitation and latitude and altitude using the existing δ18O data from 55 sites over China. The model describes as δ18Oppt = − 0.0073LAT2 +0.3261LAT − 0.0015ALT − 9.7776, and was used to generate a higher-resolution map of mean annual δ18O for precipitation over China using geographic information system software, integrating with latitude, altitude and the moisture cycle. This determination of the spatial distribution of δ18O in modern precipitation of China provides important information for ancient climate and stable isotope hydrology studies.