GLACIAL LAKE EVOLUTION BASED ON REMOTE SENSING TIME SERIES: A CASE STUDY OF TSHO ROLPA IN NEPAL
GLACIAL LAKE EVOLUTION BASED ON REMOTE SENSING TIME SERIES: A CASE STUDY OF TSHO ROLPA IN NEPAL
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DOI：
10.5194/isprs-annals-v-3-2020-633-2020
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
M. Peppa;S. B. Maharjan;S. Joshi;W. Xiao;J. Mills
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文献类型：
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作者：
M. Peppa;S. B. Maharjan;S. Joshi;W. Xiao;J. Mills
抽象。喜马拉雅冰川近年来迅速消退。该地区由此产生的冰川湖对下游社区构成潜在的灾难性威胁，特别是在气候变化的情况下。冰川湖爆发洪水（GLOFs）的可能性已经增加，研究已经评估了尼泊尔的风险，并优先考虑对几个冰川湖进行紧急和更密切的调查。Tsho Rolpa冰川湖是尼泊尔最严重的冰川湖之一。为了探讨高频遥感监测冰川湖泊演变的可行性，提出了一种基于Sentinel光学影像时间序列的冰川湖泊边界自动提取和演变流程。水体分割和矢量化使用双峰直方图从水指数。矢量化的湖泊边界进行了验证，从严格的当代无人机（UAV）为基础的摄影测量测量提取的参考数据。随后提取了四个不同时期的湖泊边界，以评估湖泊的演变，特别是在冰川终点。最后的湖泊面积估计为1.61平方公里，大大大于上次正式报告的面积。最大值为0.99米/天，平均值为0.45米/天，水平冰川退缩率估计。所报告的研究表明，遥感时间序列在监测冰湖演变方面具有潜力，这对于偏远山区的湖泊尤其重要，否则很难进入这些湖泊。
Abstract. Himalayan glaciers have retreated rapidly in recent years. Resultant glacial lakes in the region pose potential catastrophic threats to downstream communities, especially under a changing climate. The potential for Glacial Lake Outburst Floods (GLOFs) has increased and studies have assessed the risks of those in Nepal and prioritised several glacial lakes for urgent and closer investigation. The risk posed by the Tsho Rolpa Glacial Lake is one of the most serious in Nepal. To investigate the feasibility of high-frequency monitoring of glacial lake evolution by remote sensing, this paper proposes a workflow for automated glacial lake boundary extraction and evolution using a time series of Sentinel optical imagery. The waterbody is segmented and vectorised using bimodal histograms from water indices. The vectorised lake boundary is validated against reference data extracted from rigorous contemporary unmanned aerial vehicle (UAV)-based photogrammetric survey. Lake boundaries were subsequently extracted at four different epochs to evaluate the evolution of the lake, especially at the glacier terminus. The final lake area was estimated at 1.61 km2, significantly larger than the areal extent last formally reported. A 0.99 m/day maximum, and a 0.45 m/day average, horizontal glacier retreat rates were estimated. The reported research has demonstrated the potential of remote sensing time series to monitor glacial lake evolution, which is particularly important for lakes in remote mountain regions that are otherwise difficult to access.