【摘要】 为了调查和比较我国海洋型、大陆型和极大陆型冰川覆盖区大气降水、冰川、积雪和融水径流系统内稳定同位素比率的时空分布特征和冰雪相变时的现代同位素分馏过程,在2000—2003年间,按照季节和海拔高度分别对玉龙雪山、慕士塔格峰,念青唐古拉山的桑丹康桑峰以及天山乌鲁木齐河源的1号冰川积雪和冰雪融水径流进行了系统的采样研究.结果表明:在以玉龙雪山为代表的海洋型冰川区,新雪内的1δ8O呈现出显著的时间与空间变化,在冬季表现为“高度效应”,即δ18O值随海拔高度升高和气温降低而降低,反映出冬季风降水的特征;而经过融化的夏季积雪受到“降水量效应”、雪中含水量、蒸发等因素的影响,稳定同位素产生分馏变化“高度效应”空间变化比较复杂,反映出夏季风降水的特征,念青唐古拉山夏季积雪也有相似的特征.在极大陆型冰川分布的慕士塔格山地区和亚大陆型冰川分布的天山乌鲁木齐河源地区,夏季新雪中1δ8O则表现为“高度效应”或者“温度效应”.无论在海洋型冰川或者大陆型冰川分布区,经过融化或正在消融的残余积雪内都有明显的同位素分馏变化,1δ8O值比新雪高.受蒸发作用的影响,冰雪融水在流动过程中,1δ8O随海拔高度的降低、流程和流动时间的增加而增加.由于气候条件的差异,海洋型冰川区冰雪融水相变过程中的同位素分馏和化学作用都比大陆型冰川区强.更多还原

【Abstract】 In order to understand spatial and temporal variations of the stable isotopes in atmospheric precipitation,snow cover and glacial runoff in different regions of China,sampling and isotopic analysis in the systems of snow-cover,ice and glacial runoff in different types of glacial areas in China,Mt.Yulong and Samdain Kangsang in Nyainqê ntanglha Range（temperate-glacier area）,the head area of rümqi River in Tianshan Mountains（subpolar-glacier area） and Muztag（polar-glacier area）,both in summer and winter,has been carried out between 2000 and 2003.The analyzed isotopic results(δ¹⁸O) show that there is an apparent "altitude effect" in new snow fell in winter,reflecting the features of winter monsoon,but a reverse pattern,the "amount effect" in summer snow,indicating a varied altitudinal feature of summer monsoon,which is similar with that in Samdain Kangsang in Nyainqêntanglha Range.Differentially,the δ¹⁸O values in summer snowpack in the polar-glacier distributing areas of Tianshan Mountains and Muztag decrease with increasing altitude and decreasing air temperature,indicating an "altitude effect" or a "temperature effect".An marked fractionation process has occurred in residual or melting snowpack both in temperate and polar glacier areas,showing that higher δ¹⁸O values have been measured in the samples from the residual snowpack containing with meltwater than those in new snow.During the fluvial process,δ¹⁸O values in meltwater increase with decreasing altitude,increasing flowing distance and time.更多还原