极地研究

极地研究 ›› 2020, Vol. 32 ›› Issue (2): 164-176.DOI: 10.13679/j.jdyj.20190029

• 研究论文 • 上一篇    下一篇

基于Landsat-8的东南极达尔克冰川季节性表面消融信息提取

璩榆桐1,2,程晓1,2,3,4,刘岩1,2,4   

  1. 1.北京师范大学全球变化与地球科学研究院遥感科学国家重点实验室, 北京 100875;
    2.中国高校极地联合研究中心, 北京 100875;
    3.中山大学测绘科学与技术学院, 广东 珠海 519082;
    4.南方海洋科学与工程广东省实验室, 广东 珠海 519082
  • 收稿日期:2019-06-03 修回日期:2019-09-22 出版日期:2020-06-30 发布日期:2020-06-30
  • 通讯作者: 璩榆桐
  • 基金资助:

    国家重点研发计划项目(2016YFA0600103)、国家自然科学基金(41830536, 41676176, 41676182, 41406211)和钱学森空间技术实验室基金资助

Extraction of seasonal surface ablation zones in the Dalk Glacier (Antarctica) based on Landsat-8 images

Qu Yutong1,2, Cheng Xiao1,2,3,4, Liu Yan1,2,4   

  1. 1.State Key Laboratory of Remote Sensing Science, College of Global Change and Earth System Science(GCESS), Beijing Normal University, Beijing 100875, China;
    2.University Corporation for Polar Research (UCPR), Beijing 100875, China;
    3.School of Geomatics Science and Technology, Sun Yat-sen University, Zhuhai 519082, China;
    4.Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
  • Received:2019-06-03 Revised:2019-09-22 Online:2020-06-30 Published:2020-06-30

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摘要：

冰盖表面消融是气候变化和全球变暖的敏感指示剂。冰雪消融会降低地表反照率进而影响全球能量平衡, 表面融水会加剧裂隙的传播, 降低冰架稳定性进而影响冰盖物质平衡。当前, 高时空分辨率消融区分布数据的缺乏限制了南极冰盖消融发生机理和时空特征的深入探索。围绕南极冰盖大范围消融区(蓝冰、湿雪和融水)的提取研究, 提出了一种基于改进的冰雪归一化消融指数(Modified Normalized Difference Water Index Adapted for Ice, MNDWIice)的消融区自动提取方法, 采用2016年9月—2017年4月18景30m分辨率的Landsat-8数据, 获取了消融区自动提取的MNDWIice阈值, 并以东南极达尔克冰川为例, 实现了高空间分辨率的季节性消融信息提取和分析。结果表明: 在云和地形阴影干扰较小的情况下, 基于Landsat-8反射率数据计算的MNDWIice采用单一阈值(0.136)对消融区的提取精度在67.7%—94.2%之间, 平均精度为81.5%; 达尔克冰川消融面积、消融区MNDWIice均值表现出明显的季节性时空变化特征; 消融发生的时间不晚于Landsat-8数据观测的最早时间(9月7日); 消融最早出现和主要分布区在地形下降剧烈的东部接地线处。

关键词: 南极, 达尔克冰川, 消融, 改进的冰雪归一化消融指数

Abstract:

Ice sheet surface ablation is a sensitive indicator of climate change and global warming. The melting of ice and snow will reduce the surface albedo and affect the global energy balance. Surface melt water will increase the propagation of cracks, reduce the stability of the ice shelf and affect the material balance of the ice sheet. At present, the lack of high-temporal resolution data on the distribution of ablation zones limits the in-depth exploration of the mechanism and spatial-temporal characteristics of Antarctic ice sheet ablation. Focusing on the research of the extraction of the large-scale ablation zone(blue ice, wet snow and melt water) of the Antarctic ice sheet, an automatic ablation zone extraction method based on the MNDWIice (Modified Normalized Difference Water Index Adapted for Ice,) is proposed. Using Landsat-8 data with a resolution of 30 m at 18 scenes from September 2016 to April 2017, the MNDWIice threshold automatically extracted from the ablation zone was obtained, and the seasonal ablation information extraction and analysis with high spatial resolution were realized by taking the Dalk Glacier in the east Antarctic as an example. The results show that: Under the condition of less cloud and terrain shadow interference, the MNDWIice calculated based on the Landsat-8 reflectance data uses a single threshold (0.136) to extract the ablation zone with an accuracy of 67.7% —94.2%, and the average accuracy is 81.5 %; The ablation area of Dalk Glacier and the mean value of MNDWIice in the ablation zone show obvious seasonal spatiotemporal changes; Ablation occurred no later than the earlier time of Landsat-8 data observation (September 7); Ablation first appeared and mainly occurred at the eastern ground line where the terrain dropped sharply.

Key words: Antarctica, Dalk Glacier, ablation, MNDWIice