西北内陆区降水稳定同位素时空分布特征及其水汽来源  

Characteristics of Stable Isotopes in Precipitation and Its Moisture Sources in the Inland Regions of Northwest China

作　　者：张炎炎 辛存林[1] 郭小燕 张博 陈宁 史延飞 ZHANG Yan-yan;XIN Cun-lin;GUO Xiao-yan;ZHANG Bo;CHEN Ning;SHI Yan-fei(College of Geography and Environmental Sciences,Northwest Normal University,Lanzhou 730070,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070 [2]中国科学院西北生态环境资源研究院,兰州730000

出　　处：《环境科学》2024年第4期2080-2095,共16页Environmental Science

基　　金：国家自然科学基金项目(42177073);内蒙古自治区科技重大专项(zdzx2018057)。

摘　　要：综合分析西北内陆区97个研究站点的降水稳定同位素数据,并结合相关气象资料,揭示了西北内陆区降水稳定同位素δ^(18)O、δD和d-excess时空分布特征,明确了海拔、经纬度、温度和降雨量对降水δ^(18)O的影响;利用水汽通量和HYSPLIT模型追踪了大气降水的水汽来源.同时,根据关键自然地理要素的空间差异将西北内陆区划分为4个子区域,对上述内容分区域进行系统分析和对比.结果表明:(1)西北内陆区降水δ^(18)O和δD的变化范围分别为-21.20‰~1.70‰和-144.20‰~5.21‰,d-excess波动范围为-20.37‰~46.48‰,δ^(18)O、δD和d-excess均存在显著的空间变化和季节变化特征,河西内陆区和塔里木地区δ^(18)O和δD值相对偏正,柴达木-青海湖区和准噶尔-吐哈地区δ^(18)O和δD偏负.(2)西北内陆区大气降水线方程的斜率和截距均小于中国和全球大气降水线,4个子区域亦低于全球水线,其中塔里木地区斜率最低.(3)西北内陆区海拔效应为-0.04‰·(100 m)^(-1),其中河西内陆区和塔里木地区呈显著负相关;降水δ^(18)O与经度呈显著正相关,而与纬度呈不显著负相关.(4)西北内陆区普遍存在显著的温度效应,呈西北高东南低的空间特征;受气温和地形影响,降雨量效应较微弱.(5)西北内陆区水汽来源全年主要为西风水汽输送,冬季受到极地气团影响,夏季受季风水汽的入侵,部分区域会出现极端降水事件;过量氘夏季贫化、冬季富集,与相对湿度呈正相关,表明西北内陆区降水还受局地水汽再循环影响.To understand the variability of stable isotope composition in precipitation and the water vapor sources,we compared and summarized the stable isotope data from 97 studies in the inland regions of northwestern China.The whole region is divided into four subregions(the Hexi inland region,the Tarim Region,the Qaidam-Qinghai Lake Region,and Junggar-Tuha Region)based on natural geographical elements.The results of the present study were as follows:①the stable isotopes in precipitation exhibited significant spatial and seasonal variations in the inland region of Northwest China,withδ^(18)O,δD,and d-excess ranging from−21.20‰-1.70‰,−144.20‰-5.21‰,and−20.37‰-46.48‰.Theδ^(18)O andδD values were relatively positive in the Hexi Inland and the Tarim Region,and the opposite was true in the Qaidam-Qinghai Lake and Junggar-Tuha Region.②The slope and intercept of the Local Meteoric Water Line was lower than that of the China Meteoric Water Line and Global Meteoric Water Line.The four subregions were also lower than the Global Meteoric Water Line,especially the Tarim Region.③The altitude effect of theδ^(18)O value in the inland regions of northwestern China was−0.04‰·(100 m)^(−1),showing a significant negative correlation with altitude in the Hexi inland region and the Tarim Region.The longitude effect of theδ^(18)O value showed an increase,whereas the latitude effect showed the opposite trend.④The temperature effect was observed as an increasing trend from the southeast to northwest in the inland region of Northwest China.Due to the influence of temperature and topography,the effect of rainfall was weak.⑤The water vapor sources were complex in the inland region of Northwest China.The summer season was dominated by the intrusion of monsoonal vapor compared to extreme precipitation events that also occurred in some areas.The winter season was dominated by polar air vapor.The findings demonstrated the westerly vapor transport throughout the year.The results also showed the d-excess value de

关 键 词：西北内陆区 大气降水 稳定同位素 水汽来源 过量氘 

分 类 号：X142[环境科学与工程—环境科学]