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

这个由水文学、测量学和数学组成的合作项目将继续当前资助期的工作，其目标一方面是利用GRACE数据改进全球尺度的水储存变化和不同储水区流量的水文模型。另一方面，利用来自WaterGAP全球水文模型WGHM等水文模型的信息，改进GRACE距离和距离速率观测对这些地区静态和时间重力场的确定。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有助于推进项目的新估计方法。本项目旨在回答重要的水文问题，重点关注1)动态洪泛区淹没对水储存和流量的贡献（在当前资助期内继续开展工作），以及2)大陆冰川在季节性和更长时间尺度上的影响。该项目的核心是使用集成卡尔曼滤波技术开发WGHM的多目标校准工具，该工具将用于利用GRACE观测总蓄水量变化（和河流流量观测），以优化全球尺度的蓄水量和流量建模。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解决方案。这些每日模型也将应用于去混叠产品，从而提高每月解决方案的准确性。

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.