A processing system to monitor Greenland outlet glacier velocity variations at decadal and seasonal time scales utilizing the Landsat imagery
A processing system to monitor Greenland outlet glacier velocity variations at decadal and seasonal time scales utilizing the Landsat imagery
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DOI：
10.1016/j.rse.2015.07.012
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发表时间：
2015-11
影响因子：
13.5
通讯作者：
R. Rosenau;M. Scheinert;R. Dietrich
中科院分区：
文献类型：
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作者：
R. Rosenau;M. Scheinert;R. Dietrich
本文提出了一种利用可免费获得的Landsat档案资料对格陵兰冰盖出口冰川（GrIS）的全区域流速场进行监测的系统。为了处理如此大量的卫星图像，开发了一种几乎自动化的监测系统。利用先进星载热发射和反射辐射计（ASTER）的全球数字高程图V2 （GDEM-V2）进行改进的正校正，结合对具有扫描线校正器（SLC）故障的Landsat 7产品进行去条纹校正，可以获得更精确的流速信息。此外，使用自适应递归滤波方法去除异常值。在1972年至2012年的时间跨度内，从16,000多个光学多传感器Landsat场景（Landsat 1到Landsat 7）中导出了超过100,000个流速场，从而确定了长期流速趋势。此外，高时间分辨率有利于分析大量出水口冰川的季节性流速变化。对于许多主要的出口冰川，结果显示出一种加速模式，与之前发表的大多数分析一致。然而，流速变化在时空分布上并不具有均匀的规律。该研究既提供了高时间密度，又扩展了GrIS边缘的现有流速信息。最后，总的来说，这个处理链允许确定各种类型的地表位移，并可应用于其他冰川区域。
In this paper we present a monitoring system for area-wide flow-velocity fields of the outlet glaciers of the Greenland Ice Sheet (GrIS) utilizing the freely available Landsat archive. In order to process this large amount of satellite images an almost automatic monitoring system was developed. With the Global Digital Elevation Map V2 (GDEM-V2) of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) an improved orthorectification was applied which, in combination with a destriping correction of the Landsat 7 products with Scan Line Corrector (SLC) failure, leads to more precise flow-velocity information. In addition, outliers were removed using an adaptive, recursive filter approach. For the time span 1972–2012 more than 100,000 flow-velocity fields were derived from over 16,000 optical multi-sensoral Landsat scenes (Landsat 1 to Landsat 7) allowing the determination of the long-term flow-velocity trend. Moreover, the high temporal resolution facilitates the analysis of seasonal flow-velocity variations of numerous outlet glaciers. For many of the major outlet glaciers the results show an acceleration pattern that is consistent with most of the previously published analyses. However, the flow-velocity changes do not have a uniform pattern in their temporal and spatial distribution. This study provides both a high temporal densification and an extension of existing flow-velocity information of the GrIS margin. Finally, this processing chain in its generality allows for the determination of various types of surface displacements and can be applied to other glacier regions.