基于PS-InSAR技术的西藏龙巴萨巴湖冰碛坝表面形变特征分析及影响因素  

Surface Deformation Detection of the Moraine Dam of the Longbasaba Lake in Tibet of China Based on PS-InSAR Technique and Associated Influencing Factors

作　　者：张文馨 王欣[1] 冉伟杰 魏俊锋[1] 刘巧[3] ZHANG Wenxin;WANG Xin;RAN Weijie;WEI Junfeng;LIU Qiao(School of Earth Science and Spatial Information Engineering,Hunan University of Science and Technology,Xiangtan 411201,Hunan,China;Changsha Tianyi Space Technology Research Institute Co.,Ltd.,Changsha 410000,China;Chengdu Institute of Mountain Hazards and Environment,Chinese Academy of Sciences and Ministry of Water Resources,Chengdu 610029,China)

机构地区：[1]湖南科技大学地球科学与空间信息工程学院,湖南湘潭411201 [2]长沙天仪空间科技研究院有限公司,长沙410000 [3]中国科学院、水利部成都山地灾害与环境研究所,成都610299

出　　处：《山地学报》2024年第1期60-69,共10页Mountain Research

基　　金：国家自然科学基金(U23A2011,42171137)。

摘　　要：冰碛湖坝体表面形变是指示坝体稳定性的重要参数。针对高寒区冰碛坝形变监测,合成孔径雷达干涉测量(InSAR)技术仍然存在一定的技术缺陷,而基于永久散射体合成孔径雷达干涉测量(PS-InSAR)的遥感技术方面应用尚未见报道。西藏龙巴萨巴湖位于中国和印度、尼泊尔交界处,其冰碛坝具有高溃决风险。本文基于75景Sentinel-1A影像及PS-InSAR技术,以龙巴萨巴湖冰碛坝为研究对象,分析2017年2月至2023年4月期间,坝体表面形变特征及影响因素。结果表明:(1)2017-2023年龙巴萨巴坝表面体总体呈下沉趋势,平均形变速率为-2.76±0.66 mm/a。坝体明显表面下降区主要分布沿湖水岸一带,占坝体总面积的43.3%,平均下沉速率为16.82±1.55 mm/a,坝体中部存在东南-西北贯通的显著沉降区,其中最大形变永久散射点(PS点)形变速率达到-81 mm/a;中部坝体出现抬升现象,抬升区面积占坝体总面积的9.8%,平均抬升速率为17.38±2.43 mm/a,其中最大形变PS点形变速率达到43.90 mm/a;坝体外缘区变形率相对较小,在-4~4 mm/a内波动(平均形变速率为0.53±0.23 mm/a),占坝体总面积的41.11%。(2)在监测时间段内,年内不同月份沉降区面积占比为39.1%~65.8%,其中,7月沉降面积最大,占坝体总面积的65.8%;年内抬升区面积占总面积比的22.3%~38.3%,2月份坝体抬升面积最大。(3)坝体表面总体形变与坝体热通量年收支盈余、坝体内部埋藏冰发育、内部水分运移冻胀等因素有关。本研究结论可用于评估龙巴萨巴冰碛湖的危险性,为冰碛湖溃决模拟及防灾减灾提供理论依据。Surface deformation of a moraine dam is usually used as an estimation of its stability.For the deformation monitoring of moraine dam in alpine region,the technology of Synthetic Aperture Radar(InSAR)still has some technical defects in spite of its popularity,while the application of remote sensing technology based on Persistent Scatterer Interferometric Synthetic Aperture Radar(PS-InSAR)has not been reported yet.Located at the border between China and India and Nepal,the Longbasaba Lake is exhibiting the high risk of moraine dam failure.In this study,based on 75 Sentinel-1A images and PS-InSAR technology,it analyzed the dynamic deformation of the moraine dam of the Longbasaba Lake from February 2017 to April 2023.(1)In 2017-2023,there was a tendency for the Longbasaba Lake dam to subside at an average deformation rate of-2.76±0.66 mm/a.The distinct surface subsidence place in the dam was mainly distributed along the lake bank,accounting for 43.3%of the total surface area of the dam body,with an average subsidence rate of 16.82±1.55 mm/a.In the middle of the dam,there was a noticeable subsidence zone transversally running southeast-northwest,with the maximum deformation permanent scattering point(PS point)at-81 mm/a.The central dam suffered an uplift,with an uplift area accounting for 9.8%of the total area of the dam body.The average uplift rate was 17.38±2.43 mm/a,and the maximum deformation PS point deformation rate reached 43.90 mm/a.On the outer edge of the dam,the deformation rate was relatively low,fluctuating within-4~4 mm/a and an average deformation rate of 0.53±0.23 mm/a,accounting for 41.11%of the total.(2)In 2017-2023,the subsidence area in different months in a year accounted for 39.1%~65.8%,among which the subsidence size in July was the largest,accounting for 65.8%of the total,whereas the uplifting area accounted for 22.3%~38.3%of the total area,with the largest one occurred in February.(3)Surface deformation of the moraine dam of the Longpasaba Lake had a close connection with some geo-physical

关 键 词：形变监测 表面沉降 PS-INSAR 冰碛坝 龙巴萨巴湖 

分 类 号：P237[天文地球—摄影测量与遥感]