利用喀什河流域山区2017-07—2018-06大气降水同位素数据,以及流域山区温度、降水气象资料,分析了降水中δ¹⁸O、δD和氘盈余（d-excess）变化特征,讨论了δ¹⁸O与气温、降水量的关系,通过利用HYSPLI模型追踪分析流域山区大气降水的水汽来源。结果表明：（1） 流域内降水中δ¹⁸O季节变化明显,夏季δ¹⁸O同位素富集,冬季δ¹⁸O同位素贫化。（2） 不同降水类型中δ¹⁸O、δD的关系差异明显,夏季δD蒸发分馏大于δ¹⁸O、降雨大气降水线斜率及截距较小;冬季δD蒸发分馏明显减弱,降雪大气降水线斜率及截距较大。（3） 流域内大气降水同位素存在明显的温度效应,但是降水量效应不显著。（4） 流域内大气降水水汽主要来源于大西洋,受水汽远距离输送,途中加入较多二次蒸发水汽的影响,氘盈余值（d-excess）整体上偏大,但是2月氘盈余偏低,与受北极气团源地温度低、空气湿度大、水汽输送路径短影响有关。（5） 该流域夏季降水主要来源于西风环流和局地再循环水汽,冬季则受西风环流和北极气团共同影响,大西洋水汽形成的降水占研究区总降水量的68.6%,局地再循环水汽占17.1％,北冰洋水汽形成的降水占研究区总降水量的14.3%。

Using the precipitation isotopic data from July 2017 to June 2018 in the mountainous area of the Kashi River Basin, in addition to the meteorological data of and precipitation in this mountainous area, we have analyzed and discussed the seasonal variation characteristics of δ¹⁸O, δD, and d-excess in precipitation, along with the relationship between δ¹⁸O and temperature and precipitation. We used a hysplit model to trace and analyze the water vapor source of atmospheric precipitation in this mountainous area. Our findings reveal that: (1) The hydrogen and oxygen isotopes in the precipitation of the Kashi River Basin fluctuate over a wide range, with obvious seasonal variation; i. e., enrichment in summer and depletion in winter. This is due to high temperatures and a strong evaporation fractionation in summer and low temperatures and a weak evaporation fractionation in winter; (2) The intercept and slope of the local meteoric water line equation in the study area are higher than are those of the global meteoric water line, indicating that the local recycled water vapor has a strong effect on high-altitude rivers. The relationship between δ¹⁸O and δD in different precipitation types is obviously different. In summer, the evaporation fractionation of δD is greater than is that of δ¹⁸O, and both the slope and the intercept of the local meteoric water line are smaller. In winter, the evaporation fractionation of δD is obviously weakened, and the slope and intercept of the snowfall local meteoric water line are both larger; (3) There is an obvious temperature effect on the isotopes of precipitation in the Kashi River Basin. In summer, the temperature is high and the isotope are enriched. The annual precipitation effect is not significant, but there is a certain precipitation effect in autumn; (4) On the annual scale, there is a relatively large surplus of deuterium, indicating that it is affected greatly by the water vapor from the Atlantic Ocean and the local recycling water vapor. In seasonal terms, the precipitation comes from the Atlantic Ocean in summer and autumn, and the deuterium surplus is high, whereas the precipitation comes from the Arctic Ocean in winter and spring, and the deuterium surplus is low; (5) In summer and autumn the precipitation comes mainly from westerly circulation and local recycled water vapor. The precipitation formed by Atlantic water vapor accounts for 68.6% of the total annual precipitation, whereas the precipitation formed by local recycled water vapor accounts for 17.1%. In winter, the precipitation is affected by westerly circulation and the Arctic air mass, and the precipitation formed by Arctic water vapor accounts for 14.3% of the total annual precipitation.