中文摘要：

根据2011年4月~2012年3月在兰州及其周边区域永登、皋兰和榆中这4个站点所采集到的243个大气降水样品及同期相关气象资料,对兰州及其周边区域大气降水中稳定同位素的时空变化特征及其环境效应进行了分析,通过回归分析建立了大气降水线方程,同时采用HYSPLIT 4.9模型对兰州及其周边区域水汽来源进行了追踪,并建立水汽输送模式.结果表明,兰州及其周边区域的大气降水线方程为δD=7.48δ18O＋8.13,表明该区局地蒸发较强烈;在时间变化上,降水中同位素值表现为冬低夏高,而d-excess值变化趋势较为平稳,但不同时段下,也存在着一定的变化;从空间分布来看,由西至东加权平均δ18O值呈减小趋势;降水δ18O与温度呈正相关关系,而与降水量表现为负相关;在大尺度下,西风水汽、局地水汽以及东南季风水汽均对兰州及其周边区域有一定的影响,其中西风水汽占主导作用,而东南季风水汽的影响在时间上有一定的局限性,主要集中在6月初至8月初这一时段.

英文摘要：

Based on the 243 daily precipitation samples and meteorological statistics at the four stations at Lanzhou city and its surrounding area （Yongdeng, Gaolan and Yuzhong） from April 2011 to March 2012, the characteristics of stable isotopes in precipitation, as well as the correlation between stable isotopes and meteorological records, were analyzed. The precipitation equation of Lanzhou city and its surrounding area were calculated through the regression analysis, and the water vapor source of the four sites was tracked by the HYSPLIT 4. 9 model, and water vapor transmission regime was established. Results showed that the precipitation equation of 8D = 7.48 8180 ＋ 8.13 indicated intense evaporation; 8180 value was low in winter but high in summer; The variations of observed d-excess was stable all over the year, but there was variation in different time periods ; The spatial distribution showed that the weighted 8180 value decreased from the west to the east; The linear relationships between 81SO and temperature was positive correlation, but the linear relationships between 8180 and precipitation was negative correlation; The seasonal variations of 8180 indicated that westerly water vapor, local moisture and summer monsoon all had influence on this region in a large scale, but the westerly water vapor played a dominant role. However, the impact of monsoon moisture had a seasonal limitation, mainly during the period from June to early August.