Combined Hydrological Modelling and Regional Geodetic Estimation of Water Storage Variations in Large River Basins Using GRACE Data

水文学、大地测量学和数学之间的这一合作项目继续了本供资期间的工作，其目标一方面是利用GRACE数据改进对不同储水量变化和流动的全球尺度水文模拟。另一方面，应改进从Grace距离和距离-速率观测中确定这些区域的静态和时间重力场的方法，利用来自水文模型的信息，如WGHM-WGAP全球水文模型。法兰克福小组的作用将是改进水文模型WGHM，波恩小组将负责改进GRACE分析，波茨坦小组将开发和改进新的估计方法，以帮助推进项目。该项目旨在回答重要的水文学问题，重点是1)动态泛滥平原淹没对水储存和流动的贡献(继续在本供资期间开展工作)，2)在季节性和更长时间尺度上大陆冰川的影响。该项目的核心是使用整体卡尔曼滤波技术开发WGHM的多目标校准工具，该工具将被用来以最佳方式利用GRACE对总储水量变化(和河流流量观测)的观测，以改进对储水量和流量的全球规模建模。大地测量目标包括使用卡尔曼平滑方法进一步理解和改进GRACE Level-1B分析，从而确定改进的每日GRACE解。这些每日模型还将作为去锯齿产品应用，从而提高月度解的准确性。

The goal of this collaborative project between hydrology, geodesy and mathematics, which continues the work of the current funding period is, on the one hand, to improve global-scale hydrological modelling of water storage variations and flows in the different storage compartments by using GRACE data. On the other hand, the determination of the static and temporal gravitational field in these regions from GRACE range and range-rate observations shall be improved by using information derived from hydrological models such as WaterGAP Global Hydrological Model WGHM. The role of the Frankfurt group will be the improvement of the hydrological model WGHM, the Bonn group will be responsible for the improvement of the GRACE analysis and the Potsdam group will develop and improve new estimation approaches that will help to advance project. This project aims at answering important hydrological questions, focusing 1) on the contribution of dynamic floodplain inundation to water storage and flow (continuing the work in the current funding period), and 2) on the impact of continental glaciers at seasonal and longer time scales. Central to the project is the development of a multi-objective calibration tool for WGHM using Ensemble Kalman filter techniques which will be used to exploit GRACE observations of total water storage variations (and river discharge observations) optimally for improved global-scale modeling of water storages and flows. The geodetic objectives comprise the further understanding and improvement of the GRACE level-1B analysis using the Kalman smoother approach resulting in the determination of improved daily GRACE solutions. These daily models will also be applied as de-aliasing product leading to an increase in accuracy of monthly solutions.