北疆大气降水水汽源识别及其对地下水补给的指示意义

 大气降水是水循环的输入项，其同位素特征是示踪水汽来源及运动路径的有效工具。利用北疆4个大气降水观测站的同位素数据，结合HYSPLIT模式，重点分析了北疆大气降水同位素特征。区域大气降水线方程δD=7.3δ¹⁸O+3.5，反映了新疆独特的干旱气候环境。受不同降水水汽来源影响，天山及阿勒泰2个地区降水同位素特征表现不同。天山地区受西风带水汽季节性漂移的影响，氘盈余夏季低冬季高，成“V”型；阿勒泰地区常年受北冰洋水汽影响，氘盈余年内变幅不明显。尽管δ¹⁸O均表现为夏季富集、冬季贫化，但多年均值差异明显，该差异也使得利用同位素确定地下水补给来源成为可能。准东盆地东天山附近地下水主要受到来自东天山的大气降水补给，而北侧自流区地下水同位素相对贫化，与阿勒泰站大气降水同位素及氘盈余特征相似，结合地形、水文地质条件等特征，认为该区主要受克拉美丽山大气降水补给。

Identification of moisture sources in Junggar Basin and its implication for groundwater recharge

Precipitation is the input of the water cycle, and stable isotopes of precipitation (18^O and ²H) are powerful tools in tracing moisture sources and trajectories. In this paper, the characteristics of stable isotopes and deuterium excess in the precipitation are analyzed in the North Xinjiang based on observation data of four precipitation stations and HYSPLIT model. The local meteoric water line (LMWL) is established as δD=7.3δ¹⁸O+3.5, indicating the specific regional meteorological conditions. The Tianshan area and Altay area showed different isotopic characteristics due to different moisture sources. The monthly deuterium values in Tianshan area are low in summer and high in winter, which can be attributed to the seasonal drift of the westerlies. The monthly deuterium values in Altay area are constant due to the effect of arctic air mass. Although the monthly δ¹⁸O values in both areas are high in summer and low in winter, the amount-weighted averages are diverse, which makes it possible for identifying groundwater recharge areas. The intersection point of the evaporation line near Kelameili Mountain and LMWL has similar values of stable isotopes to the precipitation from Altay station, indicating that groundwater recharge from Kelameili Mountain. Groundwaters near East Tianshan Mountain have similar δ¹⁸O values, similar to the precipitation from Urumqi station, which suggesting groundwater in this area is recharged from East Tianshan Mountain.