Ground‐based Global Positioning System (GPS) observations of vertical surface displacement can be used to study terrestrial water storage (TWS) change after properly accounting for nonhydrological loading effects. This study systematically merged ground‐based GPS observations of vertical displacement into a land surface model in order to better estimate TWS. Assimilation was conducted across two snow‐dominated watersheds in the western United States using a one‐dimensional ensemble Kalman filter (EnkF). Modeled estimates were compared against TWS retrievals derived from the Gravity Recovery and Climate Experiment (GRACE) mission and in situ measurements of snow water equivalent (SWE), soil moisture, and runoff. The GPS data assimilation (GPS DA) technique improves prediction skill of TWS anomalies relative to the Open Loop (OL; model run without assimilation) when compared against GRACE TWS retrievals, especially during an extended drought period post‐2011 (e.g., correlation coefficient R_OL = 0.46 and R_GPSDA = 0.82 in the Great Basin). Furthermore, GPS DA improves SWE estimation with improved R values found over 76% and 69% of all pixels collocated with in situ stations in the Great Basin and Upper Colorado watersheds, respectively. GPS DA estimates of surface soil moisture and runoff, however, exhibit degraded performance relative to the OL due to the limited sensitivity of GPS observations to surface soil moisture variations and the lack of a dynamic surface routing scheme as well as other missing model physics (e.g., river and dam regulation, irrigation‐related water withdrawals, surface water impoundments) that are not included in the Catchment Land Surface Model.

中文翻译：

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将垂直位移的地面GPS观测资料吸收到陆地表面模型中，以改善陆地储水量估算

在适当考虑了非水文负荷影响后，可将地面垂直位移的地面全球定位系统（GPS）观测结果用于研究陆地储水（TWS）的变化。这项研究系统地将垂直位移的地面GPS观测资料合并到陆地表面模型中，以便更好地估算TWS。使用一维集合卡尔曼滤波器（EnkF）对美国西部的两个雪域进行了同化。将模拟的估计值与重力恢复和气候实验（GRACE）任务得出的TWS取值以及雪水当量（SWE），土壤湿度和径流的原位测量结果进行了比较。GPS数据同化（GPS DA）技术相对于开环（OL）提高了TWS异常的预测技能。 大盆地的R _OL  = 0.46，R _GPSDA = 0.82）。此外，GPS DA改善了SWE估计，改善了R值，发现分别与大盆地和上科罗拉多流域的原地测站并置的所有像素的76％和69％。但是，由于GPS观测值对地表土壤水分变化的敏感性有限，缺乏动态地表路径方案以及其他缺少模型物理性（例如，GPS DA估算的地表土壤水分和径流相对于OL而言，其性能下降） ，河流和大坝调节，与灌溉相关的取水量，地表蓄水量），这些都没有包含在集水区地面模型中。