The Gravity Recovery And Climate Experiment (GRACE) satellite mission recorded temporal variations in the Earth’s gravity field, which are then converted to Total Water Storage Change (TWSC) fields representing an anomaly in the water mass stored in all three physical states, on and below the surface of the Earth. GRACE provided a first global observational record of water mass redistribution at spatial scales greater than 63000 km². This limits their usability in regional hydrological applications. In this study, we implement a statistical downscaling approach that assimilates 0.5° × 0.5° water storage fields from the WaterGAP hydrology model (WGHM), precipitation fields from 3 models, evapotranspiration and runoff from 2 models, with GRACE data to obtain TWSC at a 0.5° × 0.5° grid. The downscaled product exploits dominant common statistical modes between all the hydrological datasets to improve the spatial resolution of GRACE. We also provide open access to scripts that researchers can use to produce downscaled TWSC fields with input observations and models of their own choice.

重力恢复和气候实验 (GRACE) 卫星任务记录了地球重力场的时间变化，然后将其转换为总储水量变化 (TWSC) 场，表示在所有三种物理状态下储存的水团中的异常地球表面。GRACE 在大于 63000 km ^{2的空间尺度上提供了第一个水团重新分布的全球观测记录}. 这限制了它们在区域水文应用中的可用性。在这项研究中，我们实施了一种统计降尺度方法，该方法将 WaterGAP 水文模型 (WGHM) 中的 0.5° × 0.5° 蓄水场、3 个模型的降水场、2 个模型的蒸散和径流同化，并使用 GRACE 数据在 a 0.5° × 0.5° 网格。缩小后的产品利用所有水文数据集之间的主要通用统计模式来提高 GRACE 的空间分辨率。我们还提供对脚本的开放访问，研究人员可以使用这些脚本通过输入观察和他们自己选择的模型生成缩小的 TWSC 字段。