中文摘要：

许多研究已经证明大气降水中δ^18O的变化主要和瑞利分馏过程中水汽凝结的热动力学有关,而导致温度降低水汽凝结的主要地理因素是海拔和纬度.BW模型认为大气降水中的δ^18O作为纬度和海拔的函数可以通过模拟获得,这为缺乏同位素观测地区的研究提供了必要的数据.利用BW模型,结合我国现有的55个站点降水和冰芯中18O的资料,建立了我国降水中δ^18O与纬度和海拔定量关系的模型：δ^18Oppt=0.0176LAT2＋1.1195LAT0.0016ALT23.7553.在此基础上,利用地理信息系统分析软件ArcGIS,综合了纬度、海拔以及水汽源地和水汽循环过程等影响因素产生了较高分辨率的中国降水中δ^18O的空间分布图.从一个新的研究方法揭示了我国大气降水中δ^18O的空间分布特征,为古气候与稳定同位素水文研究提供了重要资料.

英文摘要：

Studies have shown that the variation of δ^18O in precipitation is closely linked to the thermodynamics of water vapor condensation during Rayleigh distillation. The water vapor condensation is mainly controlled by low temperature as a result of increasing altitude or latitude. The BW model, established by Bowen and Wilkinson, demonstrated that δ^18O in precipitation can be modeled accurately as a function of latitude and altitude, which can estimate the isotopic composition in the absence of more data. Based on BW model, this paper established a model of the quantitative relationship between δ^18O in precipitation and latitude and altitude using the existing δ^18O data from 55 sites across China. The model was described as δ^18Oppt= -0.0176LAT^2 ＋ 1.1195LAT-0.0016ALT- 23.7553. According to this model, a higher-resolution map of mean annual δ^18O for precipitation across China has been generated using geographic information system software, integrating with latitude, altitude as well as moisture cycle. Spatial distribution of δ^18O in modern precipitation of China is revealed from a new approach, which provides important information for the study on ancient climate and stable isotopic hydrology.