地球自转对地球重力场时变特征影响的理论研究

Theoretical research of effects of earth rotation on the temporal changes of gravitational field

精密和详细测定地球重力场及其时间变化 ,是目前卫星重力测量的主要课题 .地极移动和日长变化导致地球引力位系数产生时变特性并引起重力的摄动 .根据理论力学的基本概念 ,详细推导了由于地球自转引起的地球引力位系数变化、重力摄动和垂线偏差的表达式 ,并定量地研究了极移和日长变化对测站重力观测值的影响 .同时基于EGM96地球引力位模型 ,给出了地球引力位系数 C12 和 S12 的理论公式 .

Gravitational field and its variation with time accurately were surveyed in detail.The polar motion and length-of-day(LOD) changes are known to cause the temporal variations in the gravitational field.The effects of the earth's rotation on the geopotential coefficients,gravitational perturbs and vertical deviation is modeled.It is numerically estimated,with these models,the changes in the gravity observations of some sites.We derive the formulas of the geopotential coefficients ~1_2 and ~1_2 for EGM96 model.The results suggest that the series of effects on the gravitational field due to the variations of the earth's rotation should be accounted for in high-precision space geodesy.