极地研究

极地研究 ›› 2020, Vol. 32 ›› Issue (3): 314-321.DOI: 10.13679/j.jdyj.20190055

• 研究论文 • 上一篇    下一篇

西北格陵兰冰盖水系遥感监测

李雅1, 陆瑶1, 陆欣1, 李满春1,2,3, 杨康1,2,3   

  1. 1.南京大学地理与海洋科学学院, 江苏 南京 210023;
    2.江苏省地理信息技术重点实验室, 江苏 南京 210023;
    3.中国南海研究协同创新中心, 江苏 南京 210023
  • 收稿日期:2019-10-10 修回日期:2019-11-12 出版日期:2020-09-30 发布日期:2020-09-30
  • 通讯作者: 杨康
  • 基金资助:

    国家重点研发计划项目(2018YFC1406101)、国家自然科学基金(41871327)、中央高校基本科研业务费项目(14380070)资助

Remote sensing monitoring of river networks in the Inglefield Land of the northwest Greenland ice sheet

Li Ya1, Lu Yao1, Lu Xin1, Li Manchun1,2,3, Yang Kang1,2,3   

  1. 1.School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China;
    2.Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing 210023, China;
    3.Collaborative Innovation Center of South China Sea Studies, Nanjing 210023, China
  • Received:2019-10-10 Revised:2019-11-12 Online:2020-09-30 Published:2020-09-30

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摘要：

近年来格陵兰冰盖物质损失加速, 冰面消融是造成冰盖物质损失的重要原因。每年消融期, 西北格陵兰冰盖表面都会形成规模庞大、结构复杂的冰面水系, 将大量冰面融水输送至冰盖边缘, 汇集至冰前水系并最终进入大洋, 显著影响冰盖物质平衡。然而, 目前对西北格陵兰冰盖冰面水系与冰前水系的研究很少, 冰面水系与冰前水系的形态结构特征尚不清楚。本研究选取2018年7—8月西北格陵兰盖英格尔菲尔德地区(面积4 624 km2)12景10 m空间分辨率的Sentinel-2卫星遥感影像, 增强河流横纵剖面特征, 提取了西北格陵兰冰盖的冰面水系与冰前水系, 并以水系密度与河流宽度为代表性指标, 监测冰面水系与冰前水系动态变化。结果表明: 在2018年消融期内, 西北格陵兰冰盖形成了平行状的冰面水系和树枝状的冰前水系; 冰面水系由低高程地区(<800 m)逐步向高高程地区(>1000 m)推进; 流域出口附近冰前河河宽与冰面水系密度的变化具有较好的一致性, 8月份的冰前水系新发育河宽较窄(10~30 m)的冰前河, 反映了冰面水系对冰前水系的供给作用。

关键词: 冰面水系, 冰前水系, 水系密度, 冰面消融, 格陵兰冰盖

Abstract:

Mass loss of the Greenland ice sheet has accelerated in recent years due to increases in surface meltwater runoff. Each year during the melt season, large and complex supraglacial river networks form on the northwest Greenland ice sheet surface. A large amount of meltwater is transferred to the ice sheet margin, feeds the proglacial river network and finally flows into the ocean. This process is important, because it considerably affects ice sheet mass balance and contributes to global sea rise. However, there have been few studies investigating the proglacial and supraglacial river network of the northwest Greenland ice sheet and the morphological and structural characteristics remain unclear. Here, we extracted the supraglacial and proglacial river network in the Inglefield Land(4 624 km2) from 10 m Sentinel-2 images acquired on July 25, 2018, August 14, 2018 and August 25, 2018 using the criteria of Gaussian-like backscattering cross sections and longitudinal continuity. We monitored the dynamic changes of supraglacial and proglacial river network by supraglacial drainage density and proglacial river width. We found that there are parallel supraglacial drainage patterns and dendritic proglacial drainage patterns on the northwest Greenland ice sheet during the melt season, and supraglacial river networks are gradually expanding toward higher elevation. We found a high level of consistency between proglacial river width and supraglacial drainage density.

Key words: supraglacial river network, proglacial river network, drainage density, ice surface melt, Greenland ice sheet