Using atmospherically-corrected Landsat imagery to measure glacier area change in the Cordillera Blanca, Peru from 1987 to 2010
Using atmospherically-corrected Landsat imagery to measure glacier area change in the Cordillera Blanca, Peru from 1987 to 2010
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DOI：
10.1016/j.rse.2013.08.026
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发表时间：
2014-01-01
影响因子：
13.5
通讯作者：
Nolin, Anne
中科院分区：
文献类型：
--
作者：
Burns, Patrick;Nolin, Anne
秘鲁科迪勒拉冰川的动态热带冰川正在迅速变化，这些变化预计将影响水的供应，特别是在旱季。在这项研究中，我们量化了这些水库最近的变化，提供了对1987年、1996年、2004年和2010年科迪勒拉·布兰卡冰川面积和里约热内卢圣诞老人次流域冰川面积的估计。我们通过比较使用原始场景和校正场景生成的无碎片冰川面积估计来探索大气和地形校正的影响。我们的结果表明，当应用相同的阈值时，这些修正可以对无碎片冰川面积的估计产生重大影响。从未经校正的场景得出的无碎片冰川面积估计值比从大气校正场景得出的无碎片冰川面积估计值大约少5%。我们确定，无碎片冰川面积估计对阈值和地形影响的选择最敏感。为了绘制冰川面积变化图，我们使用高分辨率卫星图像来校准我们为归一化差异雪指数(NDSI)选择的单一阈值。这一阈值被应用于所有NDSI图像，这些图像来自于在旱季结束时采集的四个经过精心挑选和大气校正的Landsat Theme Mapper(TM)场景。为了计算冰川总面积，我们手工绘制了覆盖着冰川碎片的地图，因为自动化方法在这个地区不成功。截至2010年8月，Cordillera Blanca冰川总面积为482千米，自1987年以来减少了25%。Cordillera Blanca南部的冰川平均中值海拔较低，从1987年到2010年，与北部冰川相比，冰川减少了更大比例的面积。总体而言，科迪勒拉·布兰卡冰川面积的变化似乎正在加速。2004年至2010年，科迪勒拉-布兰卡冰川面积减少的速度大约是1970年至2003年平均面积减少速度的3.5倍。(C)2013年提交人。爱思唯尔公司出版，版权所有。
The dynamic, tropical glaciers of the Peruvian Cordillera Blanca are rapidly changing and these changes are expected to affect water availability, especially during the dry season. In this study, we quantify recent changes to these water reservoirs, providing estimates of glacier area in the Cordillera Blanca and sub-watersheds of the Rio Santa for the following years 1987, 1996, 2004, and 2010. We explore the effects of atmospheric and topographic corrections by comparing debris-free glacier area estimates generated using raw scenes and corrected scenes. Our results suggest that these corrections can have a significant impact on debris-free glacier area estimates when the same threshold is applied. Debris-free glacier area estimates derived from uncorrected scenes are approximately 5% less than debris-free glacier area estimates derived from atmospherically-corrected scenes. We determined that debris-free glacier area estimates are most sensitive to the choice of threshold and topographic effects. To map glacier area change, we used high-resolution satellite imagery to calibrate our selection of a single threshold for the Normalized Difference Snow Index (NDSI). This threshold value was applied to all NDSI images, which were derived from four carefully selected and atmospherically-corrected Landsat Thematic Mapper (TM) scenes acquired at the end of the dry season. In order to calculate total glacier area, we manually mapped debris-covered glaciers, because automated methods were unsuccessful in this region. As of August 2010, the Cordillera Blanca had a total glacier area of 482 km(2), which amounts to a 25% decrease since 1987. Glaciers in the southern portions of the Cordillera Blanca, which have lower median elevations on average, lost a greater percentage of their area from 1987 to 2010, relative to their northern counterparts. Overall, glacier area change in the Cordillera Blanca appears to be accelerating. Between 2004 and 2010, glaciers in the Cordillera Blanca lost area at a rate that was approximately 3.5 times the average rate of area loss from 1970 to 2003. (C) 2013 The Authors. Published by Elsevier Inc All rights reserved.