西北干旱区尾闾湖过渡带陆面蒸发和潜水对土壤水影响的同位素分析  

Variation of hydrogen and oxygen isotopes in soil water and soil water evaporation depth around Terminal lake in arid region of Northwest China

作　　者：刘秀强 陈喜 刘琴[1,2] 张阳阳 程勤波 LIU Xiuqiang;CHEN Xi;LIU Qin;ZHANG Yangyang;CHENG Qinbo(Institute of Surface-Earth System Science,School of Earth System Science,Tianjin University,Tianjin 300072;Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim,Tianjin University,Tianjin 300072;College of Hydrology and Water Resources,Hohai University,Nanjing 210098,China)

机构地区：[1]天津大学地球系统科学学院表层地球系统科学研究院,天津300072 [2]天津市环渤海关键带科学与可持续发展重点实验室,天津300072 [3]河海大学水文水资源学院,南京210098

出　　处：《干旱区资源与环境》2021年第6期52-59,共8页Journal of Arid Land Resources and Environment

基　　金：国家重点研发计划(2017YFC0406101)资助。

摘　　要：西北干旱区尾闾湖对维持其周边生态环境的稳定至关重要。本文通过采集石羊河流域下游青土湖周边绿洲和荒漠"五水"(降水、地表水、地下水(潜水)、土壤水和植被(白刺)水)样品,分析氢氧同位素以及水线氘差Lc-excess变化特征,探究土壤水分来源及其受陆面蒸发和潜水影响深度。结果表明:绿洲至荒漠过渡区,湖水入渗补给地下水减弱,随着地下水埋深加大,土壤水变化受潜水作用减弱,进而增大陆面蒸发的影响深度。通过建立土壤水、地下水同位素随埋深变化关系,推求出潜水蒸散发的极限埋深为1.6~1.85m,该深度以内土壤水变化受陆面蒸发和地下水位埋深控制,该深度接近绿洲和荒漠交界处地下水埋深。Terminal lake is very important to maintain the stability of its surrounding ecological environment.In this paper,we collected five kinds of water(precipitation,surface water,groundwater,soil water and vegetation water)samples from oasis and desert around Qingtu lake in the lower reaches of Shiyang River Basin,analyzed the variation characteristics of hydrogen and oxygen isotopes and Lc-excess,and explored the source of soil water and its influencing depth by land surface evaporation and groundwater.The results show that:In the transition area from oasis to desert,the groundwater recharge by lake water infiltration is weakened.With the increase of groundwater depth,the effect of groundwater on soil water change is weakened,and then the influence depth of land surface evaporation is increased.By establishing the relationship between soil water and groundwater isotope variation with burial depth,it is deduced that the limit burial depth of phreatic water evapotranspiration is 1.6~1.85 m.The variation of soil water within this depth is controlled by land surface evaporation and groundwater table burial depth,which is close to the groundwater burial depth at the junction of Oasis and desert.

关 键 词：青土湖 氢氧同位素 土壤蒸发 地下水 

分 类 号：S152.7[农业科学—土壤学]