Applying Reconstructed Daily Water Storage and Modified Wetness Index to Flood Monitoring: A Case Study in the Yangtze River Basin
Applying Reconstructed Daily Water Storage and Modified Wetness Index to Flood Monitoring: A Case Study in the Yangtze River Basin
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DOI：
10.3390/rs15123192
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发表时间：
2023-06
期刊：
影响因子：
--
通讯作者：
Cuiyu Xiao;Yulong Zhong;Yunlong Wu;Hongbing Bai;Wanqiu Li;Dingcheng Wu;Changqing Wang;Baoming Ti
中科院分区：
文献类型：
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作者：
Cuiyu Xiao;Yulong Zhong;Yunlong Wu;Hongbing Bai;Wanqiu Li;Dingcheng Wu;Changqing Wang;Baoming Ti
重力恢复和气候实验（GRACE）卫星及其后继卫星GRACE Follow-On（GRACE-FO）观测到的陆地水储存异常（TWSA）为监测洪水提供了新的手段。然而，由于GRACE/GRACE-FO的时间分辨率较粗，对洪水发生机制的认识和短期洪水的监测受到限制。本研究利用统计模型，将每月 GRACE 观测数据与每日气温和降水数据相结合，重建每日 TWS。利用重建的逐日TWSA对2020年长江中下游地区发生的特大洪水事件进行了监测。此外，研究还将重建的逐日TWSA与8个全球导航卫星系统（GNSS）站的网格尺度的垂直位移进行了比较。引入修正的湿度指数（MWI）和标准化日洪水潜力指数（NDFPI），并将其与现场每日水流进行比较，以评估其洪水监测和预警的潜力。结果表明，研究区陆地水储量（TWS）从6月初开始增加，7月19日达到峰值，然后下降到9月。与每月的 GRACE 数据相比，重建的 TWSA 更好地捕捉了每日规模的水储存变化。基于重建的每日TWSA的MWI和NDFPI均比原位径流早7天超过90%，展示了其日常洪水监测的潜力。总的来说，这些发现表明重建的 TWSA 可以作为洪水监测和预警的有效工具。
The terrestrial water storage anomaly (TWSA) observed by the Gravity Recovery and Climate Experiment (GRACE) satellite and its successor GRACE Follow-On (GRACE-FO) provides a new means for monitoring floods. However, due to the coarse temporal resolution of GRACE/GRACE-FO, the understanding of flood occurrence mechanisms and the monitoring of short-term floods are limited. This study utilizes a statistical model to reconstruct daily TWS by combining monthly GRACE observations with daily temperature and precipitation data. The reconstructed daily TWSA is utilized to monitor the catastrophic flood event that occurred in the middle and lower reaches of the Yangtze River basin in 2020. Furthermore, the study compares the reconstructed daily TWSA with the vertical displacements of eight Global Navigation Satellite System (GNSS) stations at grid scale. A modified wetness index (MWI) and a normalized daily flood potential index (NDFPI) are introduced and compared with in situ daily streamflow to assess their potential for flood monitoring and early warning. The results show that terrestrial water storage (TWS) in the study area increases from early June, reaching a peak on 19 July, and then receding till September. The reconstructed TWSA better captures the changes in water storage on a daily scale compared to monthly GRACE data. The MWI and NDFPI based on the reconstructed daily TWSA both exceed the 90th percentile 7 days earlier than the in situ streamflow, demonstrating their potential for daily flood monitoring. Collectively, these findings suggest that the reconstructed TWSA can serve as an effective tool for flood monitoring and early warning.