Multiscale gravity measurements to characterize 2020 flood events and their spatio-temporal evolution in Yangtze River of China
Multiscale gravity measurements to characterize 2020 flood events and their spatio-temporal evolution in Yangtze River of China
复制标题
多尺度重力测量表征中国长江2020年洪水事件及其时空演变
DOI：
10.1016/j.jhydrol.2021.127176
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发表时间：
2021
影响因子：
6.4
通讯作者：
Chao Chen
中科院分区：
文献类型：
--
作者：
Linsong Wang;Zhenruan Peng;Xian Ma;Yuhao Zheng;Chao Chen
2020年夏季，过度降雨推动长江流域江河湖泊达到历史最高水平，但这五个洪峰被三峡水库吸收。水文过程中的大规模迁移通常会引起地球的重力响应，因此2020年的洪水事件为评估重力测量捕捉不同尺度上的水团变化的能力提供了一个很好的机会。在这项研究中，我们提供了两种常用的重力测量(即卫星GRACE-FO和地面gPhone)来表征区域洪水在流域和局部尺度上的演变，这可以归因于东亚雨季(通常称为梅雨)事件，即极端气候引起的区域水平衡效应，以及被水库吸收的洪水，即截留洪峰的人造三峡大坝(TGD)。GRACE-FO估算的陆地水储量在TGR附近有一个显著的正异常(例如，7、8月份的∼为370 mm)。GPhone在5月至9月期间测量到的重力残留量为10-20微伽。结果进一步表明，GRACE观测在小尺度TWS监测中没有明显优势，但gPhone记录很难探测到50公里外TWS质量变化的来源。特别是，gPhone记录了与天津开发区洪水流量大(即>；31,000立方米/S)直接相关的高频重力扰动，很可能用作前兆或同震信号，进一步研究水体振动或噪声源引起的地表滑坡和地下断层的活动。这项研究表明，多尺度重力解决方案的组合可以潜在地探测到由大气环流模式触发的广泛的极端气候事件，如厄尔尼诺南方涛动和伴随着海表面温度(SST)和风异常的印度洋盆地变暖。
In 2020 summer, excessive rainfall pushed rivers and lakes to record high levels over the Yangtze River Basin (YRB), but the five flood peaks were absorbed by the Three Gorges Reservoir (TGR). Mass migration in hydrological processes usually causes the Earth's gravity response, wherefore the 2020 flood events provide a good opportunity to assess the capabilities of gravity measurements in capturing the water mass changes at different scales. In this study, we presents two common gravity measurements (i.e., the satellite mission GRACE-FO and the ground gPhone) used to characterize the evolution of regional floods at a basin- and local- scale, which can be attributed to East Asian rainy season (commonly called “plum rain”) event, i.e., extreme climate-induced effects of the regional water balance, and floodwater absorbed by the reservoir, i.e., the man-made Three Gorges Dam (TGD) intercepting flood peaks. The terrestrial water storage (TWS) estimated by GRACE-FO shows a significant positive anomaly (e.g., ∼370 mm in July and August) in around the TGR. The gPhone measured gravity residual of 10–20 µgal between May and September. The results further suggest that GRACE observation does not have obvious advantages in small-scale TWS monitoring, but gPhone records is difficult to detect the source of the TWS mass change 50 km away. In particular, gPhone recorded the high-frequency gravity disturbance directly related to the high outflow (i.e., >31,000 m3/s) of TGD flood discharge, which is likely used as precursor or co-seismic signal to further study the activity of surface landslide and underground faults induced by the vibration or noise source of the water body. This study shows that the combination of multiscale gravity solutions can potentially detect a wide range of extreme climate events triggered by atmospheric circulation patterns, like El Niño Southern Oscillation and Indian Ocean basin warming accompanied by Sea Surface Temperature (SST) and wind anomalies.