地球自转变化的重力效应

The Effect of the Variation of Earth Rotation on Gravimetry

极移对重力测量的影响在前人的研究和工作中已得到了充分的考虑并有不同形式的改正公式。但是由于地轴转动速率变化的重力效应的量级很小，且限于以前的测量精度以及资料处理方法， 因而常常被忽略。随着重力测量精度的提高以及资料处理方法的改进， 有必要重新讨论该项影响。本文从推导地球瞬时自转极运动对地面台站重力测量值影响的公式入手， 将地球自转角速率变化的重力效应和极移的重力效应分离开来， 并对它们的量级分别作了估计。本文着重讨论自转角速率变化对重力测量的影响。用 Ｉ Ｅ Ｒ Ｓ 的日长变化序列和极移序列分别具体地计算了１９８２ ～１９９６ 年期间对武汉的重力测量值的影响， 结果表明， 自转角速率变化对武汉地区重力值的影响最大可达０ ．２５ ｍｉｃｒｏｇａｌ（ｐｅａｋ －ｔｏ － ｐｅａｋ） ，

The strict formula of the gravity variation caused by the movement of instantaneous rotation axis is presented.The gravity effect of the variation of the angular velocity and that of the polar motion are separated,and these practical effects are also estimated numerically.As an example,using the EOP series of IERS during 1982 and 1996,we calculated the gravity effect of the variation of earth rotation at Wuhan station.It is pointed out as a conclusion that the gravity effect of both polar motion and variation of the angular velocity must be considered in the theory and in the practical data reduction of superconductive gravimetry or absolute gravimetry,however the gravity effect of the variation of the angular velocity was usually ignored before.Nevertheless,It is necessary to correct various large error sources before one tries to solve the variation of the angular velocity and that of the polar motion from gravimetry data.