Reconstruction of a major storm event from its geomorphic signature: The Ladakh floods, 6 August 2010
Reconstruction of a major storm event from its geomorphic signature: The Ladakh floods, 6 August 2010
复制标题
DOI：
10.1130/g32935.1
复制
发表时间：
2012-06
期刊：
影响因子：
5.8
通讯作者：
D. Hobley;H. Sinclair;S. Mudd
中科院分区：
文献类型：
--
作者：
D. Hobley;H. Sinclair;S. Mudd
干旱山区的极端降水事件决定了洪水、泥石流和滑坡灾害，是地貌变化的主要驱动力。过去几十年来，世界许多地区强降水的频率增加，这就增加了记录和了解这些事件的重要性。我们使用的地貌记录重建的分布和规模的河流排放的破坏性对流风暴事件在西喜马拉雅山的内部。我们使用这个记录来估计率，规模和分布的降水和规模的泥石流所产生的同一事件。风暴于2010年8月6日在印度喜马拉雅西北部的拉达克山脉上空发生，造成1600人死亡，60多个村庄遭到破坏。它引发了许多泥石流，并大大拓宽了主要支流山谷的下游。结果表明，暴雨主要集中在距锋面4.5 km处的一个6 km宽的平行于山脉的带状区域内，其降水强度是其上方的1.30倍，最大暴雨期间30 min内降雨量至少为75 mm，是过去100年24 h最大降雨量的1.5倍。结果表明，地貌记录可以用来约束降雨强度没有气象站，也记录其分布比可以实现正常密度的仪器。
Extreme precipitation events in arid mountain regions determine flood, debris flow, and landslide hazards, and are principal drivers of geomorphic change. Increased frequency of intense precipitation in many regions of the world over the past few decades increases the importance of documenting and understanding such events when they occur. We use the geomorphic record to reconstruct the distribution and magnitude of river discharge from a devastating convective storm event in the interior of the western Himalaya. We use this record to estimate the rates, magnitudes, and distribution of precipitation and magnitude of debris flows generated by the same event. The storm occurred on 6 August 2010 over the Ladakh Range in the northwest Indian Himalaya, killing ∼600 people and devastating more than 60 villages. It triggered numerous debris flows and significantly widened the lower reaches of the main tributary valleys. We demonstrate that rainfall was concentrated in a 6-km-wide, range-parallel band centered 4.5 km up from the range front, and that within this band precipitation intensity was ∼30 times that above it. At least 75 mm of rain fell in 30 min during the heaviest part of the storm, which is at least 1.5 times the highest 24 h maximum for the previous 100 yr. The results demonstrate that the geomorphic record can be used to constrain the intensity of rainfall without meteorological stations, and also record its distribution better than could be achieved with normal densities of instrumentation.