动力地球表面形变

SURFACE TOPOGRAPHY IN DYNAMIC EARTH

地幔对流使得地球表面及核幔边界发生形变，这种由地球深部的动力学过程所引起的形变对大地水准面异常的贡献与地球内部密度异常的贡献具有相当的量级，但符号相反，而由于地表的短周期地质作用所引起的地球表面形变的屏蔽作用，这种长波长、长周期的动力地球表面形变在目前还无法直接观测出来。本文首先从观测大地水准面异常中将地球内部密度异常的贡献去掉，并根据地震层析所得出的核幔边界形变，求得了动力地球表面形变。其结果将对地球内部的动力学过程尤其是粘滞度分布提供十分有用的信息。

We calculated the surface topography in spherical harmonics up to degree and order 4 based on the core-mantle boundary topography after substracting the contribution to the geoid anomaly of the density anomaly in the earth's deep interior inferred from seismic tomography from the observed geoid anomaly.The result will be very useful to researching dynamics of the earth, especially to the viscosity pattern in the mantle.