ITRF2000无净旋转对中国大陆地壳形变的影响

INFLUENCE OF NO-NET-ROTATION OF ITRF2000 ON CRUSTAL DEFORMATION OF CHINA MAINLAND

通过计算全球14个1级板块的总角动量以及ITRF2000速度场相对NNR NUVEL1A的旋转分量,研 究了ITRF2000的无净旋转(也称无整体旋转)符合特性。结果表明,虽然ITRF2000的速度场通过50个核心站归 算到NNR NUVEL1A上,然而在研究中国大陆区域地壳形变时,它们之间的差异仍是不可忽视的,其差异性表现 为:ITRF2000的速度场相对于NNR NUVEL1A模型的速度场表现为顺时针旋转,前者速度模量大于后者;两个 速度场的差异量表现为东部大于西部,E W向差异量最大值达到5mm/a以上,N S向差异量接近4mm/a。提出 了2种消除这两个速度场之间系统差异的方法。

Fitting characteristic of No-Net-Rotation of ITRF2000 is studied by calculating the total angular momentum of 14 global plates and the rotation rate components of ITRF2000 relative to NNR-NUVEL1A.The results show that, although the velocity field of ITRF2000 was aligned to NNR-NUVEL1A, the differences between them cannot be ignored in studying regional crustal deformation in China mainland. The ITRF2000 velocity field characters the clockwise rotation relative to NNR-NUVEL1A in China mainland, and the velocity estimated from ITRF2000 is larger than that of NNR-NUVEL1A. The differences in eastern region are larger than in western region, with maximum difference up to 5 mm/a for E-W direction and 4 mm/a for N-S direction.Two methods are proposed to eliminate the systematic difference of ITRF2000 and NNR-NUVEL1A.