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冰川冻土 ›› 2023, Vol. 45 ›› Issue (2): 774-785.doi: 10.7522/j.issn.1000-0240.2023.0059

• 冰冻圈技术 • 上一篇    

联合时序InSAR和光学遥感解译的大雪山南段石冰川编目与分布特征分析

蔡佳欣1(), 何昱君1, 王晓文1,2(), 刘国祥1,2   

  1. 1.西南交通大学 地球科学与环境工程学院,四川 成都 611756
    2.高速铁路运营安全空间信息技术 国家地方联合工程实验室,四川 成都 611756
  • 收稿日期:2022-12-29 修回日期:2023-04-14 出版日期:2023-04-25 发布日期:2023-08-28
  • 通讯作者: 王晓文 E-mail:caijiaxin@my.swjtu.edu.cn;insarwxw@swjtu.edu.cn
  • 作者简介:蔡佳欣,博士研究生,主要从事雷达干涉测量及石冰川动力学研究. E-mail: caijiaxin@my.swjtu.edu.cn
  • 基金资助:
    国家自然科学基金项目(42071410);四川省科技计划项目(2021YFH0038)

Inventorying and characterizing rock glaciers in the southern Daxue Shan by combining time-series InSAR and optical image interpretation

Jiaxin CAI1(), Yujun HE1, Xiaowen WANG1,2(), Guoxiang LIU1,2   

  1. 1.Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 611756,China
    2.State-Province Joint Engineering Laboratory of Spatial Information Technology of High-Speed Rail Safety,Chengdu 611756,China
  • Received:2022-12-29 Revised:2023-04-14 Online:2023-04-25 Published:2023-08-28
  • Contact: Xiaowen WANG E-mail:caijiaxin@my.swjtu.edu.cn;insarwxw@swjtu.edu.cn

摘要:

石冰川是一种发育在高寒山区的典型冰缘地貌,其发育、分布和运动特征对高山多年冻土的状态和演化具有指示性意义。针对光学遥感影像解译难以定量判定石冰川活动状态的难题,本文联合时序合成孔径雷达干涉测量和光学遥感影像地貌解译进行石冰川探测和识别,在大雪山南段编目了860条石冰川,并统计了其关键地貌和活动参数。结果显示,研究区内石冰川由南向北分布逐渐集中,表明区域北部冰缘环境更有利于石冰川的发育;区域内石冰川发育的海拔范围在3 638~5 107 m之间,74%石冰川朝向西、西北、北、东北方向发育;97%石冰川的年均形变速率小于100 mm?a-1,并且北部区域石冰川的活动性相较于其他区域更强。基于石冰川面积与含冰量之间的经验关系模型,初步估计研究区石冰川储水量为0.963~1.445 km3。本文研究成果可为进一步开展青藏高原东南缘石冰川的时空演化规律、水文和灾害效应提供重要基础数据。

关键词: 石冰川, 大雪山, 遥感解译, InSAR地表形变

Abstract:

Rock glaciers are a common periglacial landform in alpine regions, and their distribution and movement patterns provide crucial insights into the state of mountain permafrost. Daxue Shan is situated at the transition zone between the Tibetan Plateau and Sichuan Basin, where the cold and rainy climate is ideal for the formation of maritime glaciers and periglacial landforms. However, the distribution of rock glaciers in this region has not been fully explored. In this study, we utilized 90 Sentinel-1A ascending SAR images acquired between June 2019 and June 2022 to apply the time-series interferometric synthetic aperture radar (InSAR) technique for deriving the mean annual surface displacement velocity over the southern Daxue Shan. We also comprehensively considered the kinematic characteristics from InSAR measurement and geomorphological characteristics from optical image interpretation to compile a rock glacier inventory. We classified rock glaciers into four types according to the geomorphological units at the upslope region directly connected to them, namely, talus-connected, debris-mantle-slope-connected, glacier-connected, and glacier-forefield-connected types. A total of 860 rock glaciers were compiled, with 67% being talus-connected and only 4% being glacier-connected. The rock glaciers are mainly concentrated in the northern part of the study area, indicating a more favorable periglacial environment for rock glacier development. Talus-connected rock glaciers are widespread in the study area with uniform distribution. Glacier-connected and glacier-forefield-connected rock glaciers are primarily distributed in the northeast region with strong glaciation, while debris-mantled-slope-connected rock glaciers are mainly found in the southwest area. Geomorphic and kinematic parameters were calculated to analyze the development and motion pattern of these rock glaciers. The area, length, and slope angle of rock glaciers are concentrated between 0.04~0.12 km2, 250~700 m, and 12°~24°, respectively. Compared to the other two types, glacier-connected and glacier-forefield-connected rock glaciers are relatively larger, longer, and located in gentler slopes. The distribution altitudes of the local rock glaciers are between 3 638~5 107 m, with no rock glacier development identified below an altitude of 3 915 m in this research area. The majority (74%) of rock glaciers face west, northwest, north, and northeast, with similar aspect distribution patterns shown by the four types of rock glaciers. Notably, no glacier-connected rock glacier faces southeast, south, and southwest. Overall, rock glacier activities in the study area are low, with a maximum and mean downslope velocity of 250.25 mm·a-1 and 21.97 mm·a-1, respectively, and most of them creep below 100 mm·a-1. Rock glacier activities in the northern part of the study area are relatively more evident, indicating that abundant ice within rock glaciers interacts strongly with hydrothermal conditions in this region. Correlation coefficients between the geomorphic and kinematic parameters of rock glaciers were calculated. The correlation between the geomorphic parameters of rock glaciers reflects their development characteristics. However, no evident linear relationship was found between the geomorphic and kinematic parameters, indicating a complex mechanism of rock glacier dynamics. Based on the empirical model in the previous study, the water storage of rock glaciers in this area was primarily assessed at 0.963~1.445 km3. This study presents the first rock glacier inventory in the southern Daxue Shan, revealing the distribution and motion pattern of rock glaciers in this region. The results provide essential and reliable data for further studies on rock glaciers' hydrological contributions and mountain permafrost evolution in the southeast Tibetan Plateau. The method used in this paper for rock glacier inventory can also provide a feasible technical route for compiling large-scale rock glacier inventories in western China.

Key words: rock glacier, Daxue Shan, remote sensing interpretation, InSAR displacement

中图分类号: 

  • P931.4