Climate change will affect the terrestrial water cycle during the next decades by impacting the seasonal cycle, interannual variations, and long-term linear trends of water stored at or beyond the surface. Since 2002, terrestrial water storage (TWS) has been globally observed by the Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission (GRACE-FO). Next Generation Gravity Missions (NGGMs) are planned to extend this record in the near future. Based on a multi-model ensemble of climate model output provided by the Coupled Model Intercomparison Project Phase 6 (CMIP6) covering the years 2002–2100, we assess possible changes in TWS variability with respect to present-day conditions to help defining scientific requirements for NGGMs. We find that present-day GRACE accuracies are sufficient to detect amplitude and phase changes in the seasonal cycle in a third of the land surface, whereas a five times more accurate double-pair mission could resolve such changes almost everywhere outside the most arid landscapes of our planet. We also select one individual model experiment out of the CMIP6 ensemble that closely matches both GRACE observations and the multi-model median of all CMIP6 realizations, which might serve as basis for satellite mission performance studies extending over many decades to demonstrate the suitability of NGGM satellite missions to monitor long-term climate variations in the terrestrial water cycle.

中文翻译：

---

地面水储量变异性的新变化作为未来卫星重力飞行任务的目标

气候变化将影响季节周期，年际变化以及地表水或地表以上水的长期线性趋势，从而在未来数十年内影响陆地水循环。自2002年以来，重力恢复和气候实验（GRACE）及其后续任务（GRACE-FO）已在全球范围内观测到陆地水存储（TWS）。下一代重力任务（NGGM）计划在不久的将来扩展此记录。基于耦合模型比对项目第6阶段（CMIP6）提供的涵盖2002年至2100年的多模式气候模型输出集合，我们评估了TWS可变性相对于当前条件的可能变化，以帮助定义以下方面的科学要求： NGGM。我们发现，当今的GRACE精度足以检测出陆地表面三分之一区域中季节性周期的振幅和相位变化，而精确度为5倍的双对飞行任务几乎可以解决最干旱地区以外的所有地方的这种变化。我们的星球。我们还从CMIP6集成中选择一个单独的模型实验，该实验与GRACE观测值和所有CMIP6实现的多模型中值都非常匹配，这可以作为数十年来进行卫星任务性能研究的基础，以证明NGGM卫星的适用性监测陆地水循环中长期气候变化的任务。而精确五倍的双对飞行任务则可以解决我们星球上最干旱地区以外几乎所有地方的变化。我们还从CMIP6集成中选择一个单独的模型实验，该实验与GRACE观测值和所有CMIP6实现的多模型中值都非常匹配，这可以作为数十年来进行卫星任务性能研究的基础，以证明NGGM卫星的适用性监测陆地水循环中长期气候变化的任务。而精确五倍的双对飞行任务则可以解决我们星球上最干旱地区以外几乎所有地方的变化。我们还从CMIP6集成中选择一个单独的模型实验，该实验与GRACE观测值和所有CMIP6实现的多模型中值都非常匹配，这可以作为数十年来进行卫星任务性能研究的基础，以证明NGGM卫星的适用性监测陆地水循环中长期气候变化的任务。