低阶地球引力场长期变化的确定

利用约11年的Lageos人卫激光测距（SLR）资料，反演了地球引力场系数J2和J3变化的时间序列，分析得到每年的2＝(-2.6±0.4)×10-11,3＝(-1.2±0.4)×10-11及18.6年固体潮Love数k2=0.3154±0.0070，相位滞后ε=3.1°±2.0°.由此可以对地幔滞弹和地球各圈层的动力学变化及相互作用提供高精度的天文观测约束。为了提供高精度的J2和J3变化的时间序列，可能的误差源必须考虑，如自转速率变化引起的极潮，引力场系数Jn的低阶和高阶项之间的弱的耦合等。

Determination of Long Term Variations of Low Degree Geopotential Field

The variations of geopotential coefficients J2 and J3 are determined using about 11years satellite laser ranging data to Lageos.Our results indicate that 2＝(-2.6±0.4)×10-11/a，3＝(-1.2±0.4)×10-11/a and 18.6 year period Love number k2=0.315 4±0.007 0，with phase lag ε=3.1°±2.0°,which will provide some important precise space geodetic constrains to study the Earth mantle anelasticity and the dynamical variations and interactions in the Earth.In order to obtain high precisely determined time series of J2 and J3,some small errors must be taken into account,for example,the polar tide deduced by variation of Earth rotation and the lumped effects among the low and higher geopotential terms estimated from satellite orbit analyzing.