Global groundwater droughts are more severe than they appear in hydrological models: An investigation through a Bayesian merging of GRACE and GRACE-FO data with a water balance model
Global groundwater droughts are more severe than they appear in hydrological models: An investigation through a Bayesian merging of GRACE and GRACE-FO data with a water balance model
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DOI：
10.1016/j.scitotenv.2023.169476
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发表时间：
2023-12-29
影响因子：
9.8
通讯作者：
Shum，C. K.
中科院分区：
文献类型：
--
作者：
Forootan，Ehsan;Mehrnegar，Nooshin;Shum，C. K.
在世界面临淡水供应减少的情况下，水文干旱事件的现实表现越来越重要。基于指数的干旱监测系统通常用来反映水文干旱的演变和分布，主要依靠水文模型模拟来计算这些指数。然而，最近的研究表明，模型得出的水储存估计可能有困难，充分代表现实。在这里，一种新的马尔可夫链蒙特卡洛数据同化（MCMC-DA）的方法来合并全球陆地水存储（TWS）的变化重力恢复和气候实验（GRACE）及其后续的使命（GRACE-FO）与水存储来自W3 RA水平衡模型的估计。修正MCMC-DA得出的深根土壤和地下水储量估计的总和，然后用于计算0.5 μ m标准化的地下水干旱指数全球显示GRACE/GRACE-FO DA的影响，全球指数为基础的水文干旱监测系统。我们的数值评估涵盖了2003-2021年期间，并表明，整合GRACE/GRACE-FO数据修改的季节性和年际趋势的水存储估计。极端干旱的持续时间和严重程度在表现出多年水储存波动的流域和受气候遥相关影响的流域中显著增加。
Realistic representation of hydrological drought events is increasingly important in world facing decreased freshwater availability. Index-based drought monitoring systems are often adopted to represent the evolution and distribution of hydrological droughts, which mainly rely on hydrological model simulations to compute these indices. Recent studies, however, indicate that model derived water storage estimates might have difficulties in adequately representing reality. Here, a novel Markov Chain Monte Carlo-Data Assimilation (MCMC-DA) approach is implemented to merge global Terrestrial Water Storage (TWS) changes from the Gravity Recovery And Climate Experiment (GRACE) and its Follow On mission (GRACE-FO) with the water storage estimations derived from the W3RA water balance model. The modified MCMC-DA derived summation of deep-rooted soil and groundwater storage estimates is then used to compute 0.5∘ standardized groundwater drought indices globally to show the impact of GRACE/GRACE-FO DA on a global index-based hydrological drought monitoring system. Our numerical assessment covers the period of 2003–2021, and shows that integrating GRACE/GRACE-FO data modifies the seasonality and inter-annual trends of water storage estimations. Considerable increases in the length and severity of extreme droughts are found in basins that exhibited multi-year water storage fluctuations and those affected by climate teleconnections.