抽水降深过程是计算区域水文地质参数的重要观测资料，为揭示毛乌素沙地海流兔河流域第四系潜水含水层不同时段的水文地质特征，明晰沙地潜水含水层降深差异的主控因子，本文对同一口井不同时间的4次抽水降深差异进行了系统分析。在基于抽水井附近的逐小时监测水位，首次将Bland-Altman法引入了对抽水降深过程间的差异性辨析，并利用配线法和水位恢复法求解了第四系含水层的水文地质参数来进行差异性佐证。最后，本文以流域尺度为研究系统，通过对含水层厚度、水力坡度、地下水储量变化和降水补给分析，辨析了抽水降深差异产生的主要原因。研究结果得到毛乌素沙地海流兔河流域第四系潜水含水层导水系数变化范围为3.00~4.85 m²·h^-1，且抽水前降水对包气带的下渗补给是产生抽水降深差异的主控因素。

We carried out long-term water level monitoring of a well in the quaternary sandy aquifer of Maowusu Sandy Land in China, selected four pumping processes of this well at different times in 1 year, analyzed the differences in the pumping and depth reduction processes, and systematically analyzed the possible factors of such differences. On the basis of multiple influencing factors, the main controlling factors of the differences in the depth of sandy diving aquifer were clarified, and the hydrogeological characteristics of the fourth-series diving aquifer in the Hailiutu River Basin at different times were effectively revealed. We introduced the Bland-Altman method to this study for the first time and used it to quantitatively analyze the difference between the pumping depth reduction processes. Moreover, we applied the traditional wiring method to solve hydrogeological parameters and the water level restoration method to solve the hydrogeological parameters of the quaternary aquifer for differentiation. Finally, this paper analyzed the main reasons for differences in the pumping depth by evaluating the aquifer thickness, hydraulic slope, groundwater reserves, and precipitation recharge at the watershed scale. Results showed that the variation range of water conductivity coefficient of the quaternary phreatic aquifer in Hailiutu River Basin of Mu Us Sandy Land is 3.00-4.85 m²·h^-1 and the infiltration and replenishment of the vadose belt by precipitation before pumping is the main controlling factor for the differences in pumping depth.