西鄂尔多斯是区域重要的粮食与经济作物产区。由于西鄂尔多斯地处干旱/半干旱区，浅层地下水成为维系当地生态安全与农业发展的关键水源。然而，在下垫面变化与抽水灌溉的双重干扰下，该区域浅层地下水系统的动态响应特征及其驱动机制尚不明晰。基于高分辨率综合水文模型ParFlow-CLM，结合地下水埋深观测资料对模型进行局地校准，旨在定量揭示区域地下水埋深与水储量的时空格局及驱动机制。结果表明：ParFlow-CLM模型在研究区具有较好的适用性，在农田灌溉密集区模拟与实测地下水埋深相关系数达0.8 以上，能准确表征人类活动扰动下水位的季节波动与演变趋势。地表水热过程与地下水动态的时空耦合特征显著，区内大部分区域多年平均地下水埋深在30~50 m；受季节性水热驱动，地下水埋深年内呈“春末夏初增加、秋冬季节恢复”的季节特征。定量归因分析表明，抽水灌溉是水储量变化的主导因素（贡献率86.1%，累计减水6.336 亿m3），表现为非生长季补给难抵生长季亏缺的“阶梯式”下降；相比之下，下垫面变化发挥了整体的增水效应（贡献率13.9%），以生态恢复驱动的草地扩张为正向主导因素。研究结果可为干旱/半干旱区地下水资源的可持续管理提供科学依据。

Abstract：Groundwater is essential to agricultural production and ecosystem functioning in the arid and semi-arid West Ordos region of China, an important production base for grain and cash crops. However, intensive irrigation and ongoing land-cover changes have substantially altered the regional water balance, while their respective impacts on groundwater dynamics remain poorly understood. Here, we employ the high-resolution ParFlow-CLM integrated hydrological model, locally calibrated using observed water table depth (WTD), to characterize the spatiotemporal variability of groundwater levels and storage and to quantify the effects of irrigation and land-cover change. The calibrated model reproduces observed groundwater dynamics well, with correlation coefficients exceeding 0.8 in intensively irrigated agricultural areas. It captures both seasonal waterlevel fluctuations and longer-term trends, demonstrating its ability to represent groundwater responses to human water use. Across most of the study area, the multi-year mean WTD ranges from 30 to 50 m. Groundwater levels decline from late spring to early summer, corresponding to an increase in WTD during the period of elevated water demand, and recover during autumn and winter. This seasonal cycle is closely linked to the timing and magnitude of surface water and heat fluxes, as well as to the seasonal distribution of irrigation and groundwater recharge. At the regional scale, irrigation pumping is the dominant driver of groundwater storage depletion, accounting for 86.1% of the attributed change and resulting in a cumulative reduction of approximately 633.6 million m³. Groundwater storage exhibits a stepwise decline because substantial losses during the growing season are not fully offset by recharge during the non-growing season. In contrast, land-cover change produces an overall positive effect on groundwater storage, accounting for 13.9% of the attributed change. Among the land-cover transitions, grassland expansion associated with ecological restoration represents the primary positive contributor. These findings demonstrate that irrigation pumping and ecological restoration exert contrasting influences on groundwater resources in West Ordos, with irrigation-induced depletion substantially outweighing the gains associated with land-cover change. The high-resolution modeling framework and quantitative attribution approach adopted here provide valuable tools for identifying groundwater vulnerability and disentangling the effects of human activities and ecological processes. The results also highlight the need to improve irrigation efficiency, regulate groundwater abstraction, and coordinate agricultural development with ecological restoration. Overall, these findings provide critical scientific underpinnings for the sustainable management of groundwater resources and ecological protection in arid and semi-arid regions.