澳大利亚大陆地壳垂向形变的GNSS影像学分析  

GNSS imaging analysis of vertical deformation in Australian continental crust

作　　者：宋舜跃 李水平 王欣 陶庭叶[1] 朱勇超 屈小川 SONG Shunyue;LI Shuiping;WANG Xin;TAO Tingye;ZHU Yongchao;QU Xiaochuan(School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,China;Wuhan Gravitation and Solid Earth Tides,National Observation and Research Station,Wuhan 430071,China)

机构地区：[1]合肥工业大学土木与水利工程学院,合肥230009 [2]武汉引力与固体潮国家野外科学观测研究站,武汉430071

出　　处：《地质科技通报》2025年第1期298-307,共10页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42004001);武汉引力与固体潮国家野外科学观测研究站开放基金项目(WHYWZ202107);中央高校基本科研业费专项(JZ2022HGTB0268)。

摘　　要：在地壳垂向形变监测中全球导航卫星系统(GNSS)技术和合成孔径雷达干涉测量(InSAR)技术分别存在空间分辨率和时间分辨率不足的问题,而GNSS影像学方法基于离散的GNSS站点速度生成地壳垂直运动的图像,可以直接揭示地壳垂直运动的连续空间特性。使用GNSS影像学方法,研究了澳大利亚大陆地壳垂向形变,并通过棋盘格检验和交叉检验的方法对GNSS地壳垂直运动影像的可靠性进行了分析。结果表明GNSS影像学方法可以有效地剔除一些粗差的影响,并减少GNSS地壳垂直运动影像中出现零碎图斑和规则圆弧形突变边缘的问题,但同时也会剔除掉一些峰值和突变值,从而使生成的影像出现过度平滑的问题。GNSS地壳垂直运动影像表明澳大利亚将近98%的地区正在沉降,只有在澳大利亚北部部分地区和东部极小部分地区地壳呈上升运动,沉降和上升的量级基本在−3~1 mm/a之间。所有地区的垂直运动平均值为−0.76 mm/a,中值为−0.72 mm/a。本研究证实GNSS影像学方法具有合理性与正确性,GNSS地壳垂直运动影像能够准确获取大范围、高时空分辨率的地壳垂向形变,有助于揭示区域地壳垂向形变时空变化的细节特征。[Objective]In the study of vertical crustal deformation,the GNSS technique and InSAR technique have insufficient spatial and temporal resolutions,respectively.To better explore the continuous spatial characteristics of crustal vertical deformation,images of crustal vertical motion can be generated based on discrete GNSS station velocities;thus,the continuous spatial characteristics of crustal vertical motion can be directly revealed.[Methods]In this work,the vertical deformation of the Australian continental crust is studied via GNSS imaging.GNSS imaging was first proposed by Professor Hammond of the Nevada Geodesy Laboratory,who used this method to obtain high-resolution images of crustal vertical deformation(GNSS images)in California and Nevada,USA.As a method to obtain images of continuous crustal vertical deformation with the help of image processing technology,it can automatically eliminate the influence of abnormal observations in the study area and reveal the spatiotemporal variation characteristics of crustal vertical deformation.First,the coordinate time series of the GNSS station in Australia are used to obtain the station velocities and uncertainties via a robust nonparametric estimation method,namely,the median interannual difference adjusted for skewness(MIDAS);second,the relationships between stations with the spatial structure function(SSF)are constructed;third,a median spatial filter(MSF)is constructed and applied to eliminate velocity outliers and enhance regional common characteristics;finally,the velocity field is densified using image processing technology,and spatially continuous GNSS images in the study areas are generated.In addition,checkerboard tests and cross-checks are carried out to verify the reasonability of GNSS imaging and the reliability of the GNSS images generated with the stations in these areas.Moreover,when the velocities before and after MSF were compared,the necessity of MSF in GNSS imaging was verified,and the causes of oversmoothing and the formation of arcuate abrupt bou

关 键 词：GNSS影像学 垂向形变 澳大利亚 影像学分析 

分 类 号：P407[天文地球—大气科学及气象学]