GRACE satellite data are widely used to estimate groundwater storage (GWS) changes in aquifers globally; however, comparisons with GW monitoring and modeling data are limited. Here we compared GWS changes from GRACE over 15 yr (2002–2017) in 14 major U.S. aquifers with groundwater‐level (GWL) monitoring data in ~23,000 wells and with regional and global hydrologic and land surface models. Results show declining GWS trends from GRACE data in the six southwestern and south‐central U.S. aquifers, totaling −90 km³ over 15 yr, related to long‐term (5–15 yr) droughts, and exceeding Lake Mead volume by ~2.5×. GWS trends in most remaining aquifers were stable or slightly rising. GRACE‐derived GWS changes agree with GWL monitoring data in most aquifers (correlation coefficients, R = 0.52–0.95), showing that GRACE satellites capture groundwater (GW) dynamics. Regional GW models (eight models) generally show similar or greater GWS trends than those from GRACE. Large discrepancies in the Mississippi Embayment aquifer, with modeled GWS decline approximately four times that of GRACE, may reflect uncertainties in model storage parameters, stream capture, pumpage, and/or recharge rates. Global hydrologic models (2003–2014), which include GW pumping, generally overestimate GRACE GWS depletion (total: approximately −172 to −186 km³) in heavily exploited aquifers in southwestern and south‐central U.S. by ~2.4× (GRACE: −74 km³), underscoring needed modeling improvements relative to anthropogenic impacts. Global land surface models tend to track GRACE GWS dynamics better than global hydrologic models. Intercomparing remote sensing, monitoring, and modeling data underscores the importance of considering all data sources to constrain GWS uncertainties.

中文翻译：

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用美国主要含水层的监测和模拟比较GRACE卫星的地下水储量变化

GRACE卫星数据被广泛用于估算全球含水层中的地下水存储（GWS）变化；但是，与GW监视和建模数据的比较是有限的。在这里，我们比较了美国14个主要含水层中GRACE超过15年（2002-2017年）的GWS变化与约23,000口井中的地下水位（GWL）监测数据以及区域和全球水文和地面模型。结果显示，根据GRACE数据，美国西南部和中南部的六个含水层中的GWS趋势呈下降趋势，在15年内总计−90 km ³，与长期（5-15年）干旱有关，超过米德湖的面积约2.5倍。其余大部分含水层的GWS趋势稳定或略有上升。GRACE得出的GWS变化与大多数含水层中的GWL监测数据一致（相关系数，R = 0.52-0.95），表明GRACE卫星捕获了地下水（GW）动态。区域GW模型（八个模型）通常显示出与GRACE相似或更大的GWS趋势。密西西比河蓄水层中的较大差异（模拟的GWS下降了GRACE的四倍）可能反映了模型存储参数，溪流捕获，抽水和/或补给率方面的不确定性。全球水文模型（2003-2014年）（包括GW抽水）通常高估了美国西南部和中南部大量开采的含水层中的GRACE GWS损耗（总计：约-172至-186 km ³），约为2.4倍（GRACE：- 74公里³），强调需要对人为影响进行建模改进。全球陆地表面模型往往比全球水文模型更好地追踪GRACE GWS动态。遥感，监测和建模数据的相互比较强调了考虑所有数据源以限制GWS不确定性的重要性。