Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions
Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions
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DOI：
10.3390/rs9070640
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发表时间：
2017-06
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通讯作者：
Ingmar Nitze;G. Grosse;B. Jones;C. Arp;M. Ulrich;A. Fedorov;A. Veremeeva
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文献类型：
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作者：
Ingmar Nitze;G. Grosse;B. Jones;C. Arp;M. Ulrich;A. Fedorov;A. Veremeeva
湖泊是北方永久冻土区普遍存在的景观特征。它们对碳、能源和水的通量有很大的影响，对气候变化的反应也相当快。以足够精确的时空分辨率监测北部高纬度地区的湖泊变化，对于理解驱动湖泊变化的潜在过程至关重要。迄今为止，多年冻土区湖泊变化研究主要基于多种不同来源、图像采集周期和单快照以及局部分析，阻碍了不同区域的比较。在此，我们提出了一种基于机器学习的Landsat数据多光谱指数（TM、ETM+、OLI）稳健趋势分类和基于目标的湖泊检测方法，分析和比较了1999年至2014年北部多年冻土带四个不同研究地点（阿拉斯加北坡、阿拉斯加西部、雅库特中部、科雷马低地）的个体、局部和区域湖泊动态。阿拉斯加北坡（- 0.69%）、阿拉斯加西部（- 2.82%）和Kolyma低地（- 0.51%）湖泊面积变化的区域格局主要包括热岩溶湖扩张导致的湖泊面积增加，但更多的主要湖泊面积损失是由灾难性湖泊排水事件造成的。相比之下，中部雅库特地区的湖泊面积显著增加了48.48%，这可能是由于研究期间后半段气候条件更加温暖和潮湿所致。在所有研究区域内，湖泊动态的变化与多年冻土特征、景观位置（即高地与低地）和地表地质的差异有关。利用全球可用的Landsat数据和统一的方法处理来自多光谱指数强劲趋势的输入数据，我们展示了北部多年冻土区湖泊变化分析的可转移性、可扩展性和一致性。
Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (−0.69%), Western Alaska (−2.82%), and Kolyma Lowland (−0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.