GPS观测网络中共模分量的相关加权叠加滤波  

Correlation weighted stacking filtering of common-mode component in GPS observation network

作　　者：田云锋[1,2] 沈正康[2,3] 

机构地区：[1]中国地震局地壳应力研究所,中国北京100085 [2]中国地震局地质研究所,地震动力学国家重点实验室,中国北京100029 [3]北京大学地球与空间科学学院,中国北京100871

出　　处：《地震学报》2011年第2期198-208,共11页Acta Seismologica Sinica

基　　金：中国地震局地壳应力研究所所长基金(ZDJ2009-01);地震行业科研专项(200708002);国家重点基础研究发展计划(2004CB418403);科技部重点实验室项目(LED2008A05)资助

摘　　要：基于GPS台站间的位置时间序列相关分析,提出了一种去除共模分量(common-mode component,简写为CMC)的空间滤波方法相关加权叠加滤波.该方法采用台站间的相关性大小作为空间滤波的权重,同时考虑距离、总体相关性水平等因素,无需现有滤波方法所需的空间均匀分布这一假设.针对美国板块边界计划中310个GPS连续台、中国境内的33个GPS连续台和全球约200个GPS连续台数据的空间滤波结果表明,在200km尺度上仍存在较强的CMC.随着距离的增加,CMC的共性逐渐减弱,直至2000km左右不再相关.与传统的区域叠加滤波方法相比,针对小尺度网络,经过相关加权叠加滤波后,残差RMS改进多为5%-20%,且能够分离出单站异常和不同空间尺度上的CMC,提高了检测弱构造信息的能力,对于分析各类CMC的起源也具有参考价值.Based on the correlation analysis of position time series for GPS stations,a spatial filtering method,correlation weighted stacking filtering,was put forward to remove common-mode component（CMC）.This method uses correlation coefficients as weights in spatial filtering,and takes into account such factors as site distances and the whole level of correlation.There is no need for the assumption of spatial homogeneity as adopted by current filtering techniques.The method has been used to analyze the position time series of 310 GPS stations in the U S PBO（Plate Boundary Observatory）network,33 sites in China and about 200 global GPS stations.The results show that there are obvious CMC of 200 km scale,and the common part of CMC for different stations decreases as the baseline distance increases.Near about 2000 km,the position residual time series of GPS sites are usually no longer correlated.Compared to the traditional regional stacking filtering,the correlation weighted stacking filtering can generally introduce 5%—20% RMS（root mean square）residual improvement for small scale GPS networks.It can also extract CMC of individual spatial scale and separate single site anomalies,increasing our ability in detecting weak tectonic signals and searching for CMC origins.

关 键 词：GPS 位置时间序列 共模分量 空间滤波 相关系数 

分 类 号：P315.721.5[天文地球—地震学]