南极板块运动新模型的确定与分析

New model of Antarctic plate motion and its analysis

自1995年起,国际南极研究科学委员会（SCAR,the Scientific Committee on Antarctic Research）组织实施全南极国际GPS（Global Positioning System）联测.本文运用GAMIT/GLOBK软件分析了从1997到2004年的SCAR GPS数据和在南极的一些GPS永久跟踪站数据.数据处理分为两步,第一步：运用GAMIT软件进行单天解算,估计站位置、轨道等参数,其数据源主要有以下三类：（1）SCAR GPS观测站;（2）南极的连续跟踪站;（3）南极及其周边的部分IGS站;第二步：运用GLOBK软件加入SOPAC（Scripps Orbit and Permanent Array Center）的全球GPS子网（IGS1、IGS2、IGS3）进行全球网平差解算测站位置和速度.然后,参照地质构造讨论网的形变,分析了南极板块的现今地壳运动.GPS结果显示南极板块的欧拉角速度是0.224（°）/Ma,旋转极的位置为（58.69°N,128.29°W）,这与NNR-NUVEL-1A预测的和一些前期GPS研究的成果有着较大的不同.相对于澳大利亚板块,本文结果同其他模型的旋转角速度相差约0.01（°）/Ma,旋转极的位置相差在4°以内,不同模型之间的差异相对较小.这为描述南极板块运动提供了一个更为精确的新的运动模型.

Since 1995,Antarctic crustal movement campaign has been taking place by Scientific Committee on Antarctic Research（SCAR）every year.We analyse SCAR campaign data from 1997 to 2004 and some continuous GPS stations in Antarctica using GAMIT/GLOBK software.The data analysis involves two major procedures.The first procedure uses the GAMIT software to estimate parameters such as station position and orbital trajectory on a daily basis for a given 24-hour interval from the union of three data sets：（1）the campaign stations,（2）the continuously operating GPS stations in Antarctica,（3）long-running continuous GPS stations around Antarctica.In the second procedure,we combine the daily solutions with global GPS sub-networks（IGS1,IGS2,IGS3）,which is provided by Scripps Institution of Oceanography（SIO）,using the GLOBK software in a ＂regional stabilization＂ approach in order to estimate the positions and velocities.Then we discuss present-day crustal movement of Antarctic plate.The position of the rotation pole（58.69°N,128.29°W）and its rate（0.224（°）/Ma）derived from SCAR GPS data is significantly different from the NNR-NUVEL-1A estimations or from some GPS results for the Antarctic tectonic plate.As for the relative angular motion between Antarctic and Australian,the differences between the results from the paper and some other models are better.All differences for rotation rate are smaller than 0.01（°）/Ma,and for rotation pole are smaller than 4°.The GPS results give the new and precise model on Antarctic plate motion.