地球非对称变形的最新观测证据

THE NEWEST OBSERVATIONAL EVIDENCE ON ASYMMETRICAL DEFORMATION OF THE EARTH

根据 2 0 0 1年 3月IERS公布的全球近 6 0 0个GPS站、SLR站及VLBI站的站坐标、速度及它们的误差估计 ,研究了地球的现今非对称变形 .结果表明 ,以赤道为界 ,北半球目前仍处于挤压变形中 ,而南半球则处于扩张变形中 .若以 90°E和 90°W经线为界 ,则以 180°经线为中心线的太平洋半球处于挤压变形中 ,而以 0°经线为中心线的大西洋半球 ,则处于拉张变形中 .这种变形再次证明地球处于双重非对称变形之中 ,而且 ,如果以 6 36 6 74 0 .0m作为理想地球平均曲率半径 ,根据空间大地测量结果算得的体积变化率达到 0 .6 6 5× 10 1 2

Based on the coordinates, velocities and their error estimations of 595 GPS, SLR and VLBI stations issued by IERS in March 2001, the current asymmetrical deformation of the Earth is studied. The results show that the northern hemisphere of the Earth is undergoing compressive deformation, and the southern hemisphere is undergoing extensional deformation with the equator as the boundary. If the longitude line of 90°E and 90°W is taken as the boundary, the Pacific hemisphere (with 180° as its central longitude) is undergoing compressive deformation, and the Atlantic hemisphere (with 0° as its central longitude) is undergoing extensional deformation. The deformation patterns indicate again that the Earth is undergoing some dual-asymmetrical deformation. Moreover, taking 6 366.740 km as the standard mean curvature radius of the Earth, the velocity of volume change calculated from the data of space geodesy is 0.665×10 12 m 3/a.