TanDEM-X双站SAR干涉测量及研究进展

较全面、系统地介绍了Tan DEM-X/Terra SAR-X双站SAR科学计划,重点涉及其科学目标、Tan DEM-X卫星参数、轨道结构以及干涉数据获取模式等相关内容,并讨论了双站SAR成像、极化In SAR和数字波束成形等干涉测量新技术及其研究进展。这些双站SAR新技术的实现将大大地推动SAR干涉测量在全球地形测绘、冰川学、海洋学及地质学等领域中的应用。     

基于Landsat-7ETM+SLC-OFF影像的山地冰川流速提取与评估——以Karakoram锡亚琴冰川为例

Landsat-7机载扫描行校正器（Scan Line Corrector,SLC）失效后的ETM+影像（SLC-OFF影像）约有22%的数据缺失,严重限制了该影像在冰川研究中的应用,特别对长期缺乏高质量遥感影像的高亚洲地区冰川运动连续监测产生较大影响。以Karakoram 中部最大的锡亚琴冰川为例,初步评估了Landsat-7 ETM+SLC-OFF影像在山地冰川表面流速提取方面的适用性和可行性。选取2009年和2010年两景SLC-OFF影像,运用局部直方图匹配法（Local Linear Histogram Match,LLHM）和加权线性回归法（Weighted Liner Regression,WLR）修复缺失数据条带,并利用亚像元互相关方法对修复后两景影像进行冰川表面流速估算。结果表明,LLHM和WLR两种方法均能有效修复冰川区Landsat-7 SLC-OFF影像,其冰流估算结果与同期Landsat-5TM 影像的冰流结果较为一致,三者冰流速估算精度分别为±5.9m ·a^-1、±6.3m ·a^-1和±4.0m ·a^-1,验证了Landsat-7 SLC-OFF 影像在山地冰川流速监测中的应用潜力。     

基于Sentinel-2影像的巴尔托洛冰川冰面湖研究

冰面湖是冰川的重要组成部分,是冰川消融的指示器,不仅对全球气候变化响应迅速,而且对了解和掌握区域水资源信息意义重大。本文基于Sentinel-2遥感数据,利用随机森林算法,对巴尔托洛冰川冰面湖进行识别提取,并基于提取结果分析研究区冰面湖的空间分布特征,以及冰面湖面积、数量与冰川高程的关系。本文冰面湖提取的准确率达96.07%,完整率达92.18%,错误率为11.59%;识别出巴尔托洛冰川冰面湖567个,面积为249.46～37 134 m²;冰面湖多分布在距冰川末端3～26 km处,其中海拔3800～4300 m之间冰面湖数量最多,面积普遍较大,平均面积为1922 m²;随着高程的升高,冰面湖的数量和面积逐渐减少,在高程5300 m以上冰面湖数量仅为15个,平均面积为356 m²;高程升高导致冰面温度降低,是冰面湖数量和面积骤减的主要原因。     

Surface velocity monitoring of Skamri Glacier from 2018 to 2021 based on Landsat-8 images北大核心CSCD

Skamri Glacier is the largest glacier in China, and it is a surge-type glacier. The study on the charac⁃ teristics of glacial movement is of great significance for early warning of glacial disasters caused by glacier surge. In this paper, 20 pairs of Landsat-8 images from 2018 to 2021 were selected to extract the surface veloci⁃ ty of Skamri Glacier using optical image feature tracking method, analyze the uncertainty of velocity, and ana⁃ lyze the temporal and spatial changes characteristics of velocity of the glacier. The results show that there are ob⁃ vious spatial differences in the surface velocity of Skamri Glacier. During the period from January 2018 to June 2019, the velocity of the south tributary of Skamri Glacier is much greater than that of its north tributary（west）, while during the period from June 2019 to November 2021, it presents completely opposite spatial characteris⁃ tics, which is mainly due to the sudden increase of the velocity of the north tributary（west）in June 2019. Ac⁃ cording to the results of velocity changes from 2018 to 2021, it is found that the north tributary（west）surges in June 2019 and is still in the surge period until November 2021. The north tributary（west）glacier terminus will advance about 320 m towards the main glacier from August 2020 to September 2021;The velocity of the south tributary has been very large during the study period, and the maximum velocity reaches 441 m·a-1;The veloci⁃ ty of the north tributary（east）of Skamri Glacier increased sharply in July 2021, and the tributary may surge;The velocity of the main glacier of Skamri Glacier increased significantly after the confluence of the south tribu⁃ tary and the surge of the two north tributaries. In addition, there are temporal and spatial differences in the eleva⁃ tion distribution of the maximum velocity of the main glacier and its tributaries in this area. © 2022 Science Press (China). All rights reserved.     

山地冰川运动地基InSAR监测试验

利用IBIS-L地基InSAR系统,在新疆和静县备战铁矿附近的一处山地冰川进行了冰面流动速度连续观测。结果表明,该冰川平均表面流动速度为2.63mm/h,且在空间上呈现从冰川中上游向下游递增的趋势,但冰川末端的流动速度明显减缓。在观测时间内,冰川运动状态较为平稳,基本处于连续滑动状态。研究结果为揭示冰川基本性质及其动力学机制提供了重要的基础数据,初步验证了地基InSAR技术测量冰川表面流速的可行性及其广阔的应用前景。