消除气压效应估算黄土潜水的蒸发蒸腾强度  

Estimation of groundwater evapotranspiration rate in the loess phreaticaquifer by removing the barometric effect

作　　者：程东会[1,2] 袁靖[1,2] 齐丽军 CHENG Donghui;YUAN Jing;QI Lijun(School of Water and Environment,Chang’an University,Xi’an,Shaanxi 710054,China;Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region,Chang’an University,Ministry of Education,Xi’an,Shaanxi 710054 China;Institute of Earth Environment,Chinese Academy of Sciences,Xi’an,Shaanxi 710054,China)

机构地区：[1]长安大学水利与环境学院,陕西西安710054 [2]长安大学干旱区地下水文与生态效应教育部重点实验室,陕西西安710054 [3]中国科学院地球环境研究所,陕西西安710054

出　　处：《水文地质工程地质》2021年第2期8-14,共7页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助项目(41972248);陕西省自然科学基础研究计划(2019JM-146)。

摘　　要：潜水蒸发蒸腾(ETg)是干旱半干旱地区浅埋深地下水最主要的排泄方式,也是地下水系统中重要的均衡项。如果存在气压效应,用于估算地下水蒸发蒸腾强度的传统水位波动法则不适用。以黄土潜水为例,提出了一种基于水位变化和大气压变化规律的水位图方法,用于消除气压效应以获取潜水蒸发蒸腾强度。研究表明,大气压变化通常在午夜前,一般为22:00—24:00,会出现一个峰值,该时间段气压效应可以忽略,而且潜水蒸发蒸腾强度最小,此时潜水位的变化速率相当于净补给速率;在获取潜水净补给强度后,选择第二个时间段,0:00—4:00,此时潜水蒸发蒸腾强度最小,且气压一般处于连续下降阶段,可以用来估算气压效应系数。在此基础上,可利用水位均衡和水位波动法方便地估算潜水蒸发蒸腾强度。该方法数据获取容易,估算结果也较为准确。Groundwater evapotranspiration(ETg)is the most important dischargeway of shallow groundwater in arid and semi-arid areas,and also is a significant component of the water budget in groundwater systems.When groundwater levelsare interfered with barometric effect,the traditional water table fluctuation method for estimation of the ETg rate cannot be directly employed.This paper proposes a hydrographical method for removing the barometric effect on the ETg rateestimation using water-table fluctuations based on the changes ingroundwater levels and barometric pressure.The results illustrate that thechangesin barometric pressure usually reach the peak before midnight,generally between 22:00 and 24:00 when the barometric effect can be ignored,and the evapotranspiration rate is the minimum and therefore thegroundwater level changes rate at this time interval is equivalent to the net recharge rate.Furthermore,the second time period between 0:00 and 4:00 when the ETg rate is negligible and the barometric pressure is generally in a continuous decline,is then selected to estimate the barometric efficiency.On the basis of these analyses,the ETg rate can be readily estimated by the groundwater level balance method and the water table fluctuation method.The data required in theproposed methodare easy to obtain and the estimated ETg ratesare relatively accurate.

关 键 词：潜水蒸发蒸腾 气压效应 水位波动法 黄土潜水 

分 类 号：P641.2[天文地球—地质矿产勘探]