ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    基于改进的水位昼夜波动法的小时尺度潜水蒸散发研究

    Research on Hour-scale Groundwater Evapotranspiration Based on Modified Method of Diurnal Water Table Fluctuation

    • 摘要: 基于水位昼夜波动计算潜水蒸散发(ETG)的方法应用广泛,但已有的水位昼夜波动法忽略了夜间地下水对毛细水的补给,低估了地下水侧向补给量,从而低估了ETG。本次研究提出考虑夜间毛细水恢复速率的改进方法,并结合一维饱和非饱和水流模型(HYDRUS-1D)和野外实测数据对改进方法进行了验证。结果显示:基于模型的不同土质条件下,Loheide方法的相对误差均大于45%,且误差随实际ETG与水位埋深的增大而增大;而改进方法的计算精度明显提高,相对误差均小于4%。结合实测数据的验证中,改进方法计算的小时尺度ETG与潜在蒸散发具有更好的相关性。上述结果表明,改进方法显著提升了小时尺度ETG的计算精度,可有效应用于半干旱地区小时尺度潜水蒸散发计算,为定量研究地下水与植物生态的相互关系提供了技术支撑。

       

      Abstract: Groundwater evapotranspiration (ETG) is widely estimated using methods based on diurnal water table fluctuations. However, these methods fail to account for the recharge of capillary water by groundwater at night, which results in an underestimation of ETG due to the underestimated lateral recharge of groundwater. This study proposes a modified method that takes into account the capillary water recovery rate at night. HYDRUS-1D, a one-dimensional saturated unsaturated flow model, and field measurements are used to evaluate the modified method. Results demonstrate that the relative errors of the Loheide method are all larger than 45% under various soil conditions based on the model. The errors rise as the water table depth and real ETG both rise. The modified method significantly improves estimation accuracy, with an error of less than 4%. The hour-scale ETG estimated by the modified method shows a stronger association with potential evapotranspiration in the validation of the measured data. According to the above results, the modified method considerably raises the hour-scale ETG calculation accuracy. It can also be applied successfully to hour-scale ETG calculations in semi-arid areas, offering technical support for quantitative studies on the connection between groundwater and plant ecology.

       

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