大兴安岭外源水补给的水量平衡与同位素证据

Water balance and isotopic evidence of external water supply in Daxing’an Mountains

通过对大兴安岭北部呼玛河流域降水与径流关系以及河水与地下水的同位素分析,讨论了呼玛河流域多年冻土区地表水与地下水之间的转化关系。结果表明:冬季河流接受泉水补给,冻土层下水通过冻土层中的不冻带补给河水;呼玛河流域径流量与蒸散发量之和大于降水量,且当地地表水和地下水的氢氧同位素比当地降水贫化,补给河流的冻土层下水接受非本流域的降水补给;补给河流的冻土层下水的氢氧同位素特征与西藏河流的氢氧同位素接近,西藏高原可能是大兴安岭的补给源区。

By analyzing the relationship between precipitation and river runoff in the Huma River Basin in the north of Daxing’an Mountains and isotopic of river and groundwater, this paper discusses the transformation relationship between surface water and groundwater in permafrost area of Huma River Basin. The results show that the rivers are recharged by springs in winter, and the sub-permafrost water supplies the river through the unfrozen zone in the frozen soil layer. The sum of runoff and evapotranspiration in the Huma River Basin is larger than the precipitation, and the sub-permafrost water, which supplies the river, receives the precipitation supplement from exotic basins under the circumstance of hydrogen and oxygen isotopes of local surface water and groundwater are less than that of local precipitation. The hydrogen and oxygen isotopic characteristics of the sub-permafrost water, which supplies the river, are close to that in Tibet, which indicates that the Tibet plateau may be the source of water supplement in Daxing’an Mountains.