SNREI地球对表面负荷和引潮力的形变响应  

DEFORMATION RESPONSE OF A SNREI EARTH TO SURFACE LOADS AND TIDAL FORCES

作　　者：徐建桥[1] 孙和平 

机构地区：[1]中国科学院测量与地球物理研究所动力大地测量学重点开放实验室,武汉430077

出　　处：《地球物理学报》2003年第3期328-334,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金 ( 40 1740 2 2 ;4992 5 411);中国科学院知识创新项目 (KZCX2 - SW- 131) .

摘　　要：基于PREM模型 ,利用非自转、球型分层、各向同性、理想弹性 (SNREI)地球的形变理论 ,讨论了地球在不同驱动力作用下的形变特征 .采用地球位移场方程的 4阶Runge Kutta数值积分方法 ,解算了在表面负荷和日月引潮力作用下地球表面和内部形变和扰动位 ,并给出了地球表面的负荷Love数和体潮Love数 .结果表明在固体内核中的形变很小 ,液核中低阶 (n <10 )负荷位移随半径的变化非常复杂 .当负荷阶数超过 10时 ,地核中的形变和扰动位都很小 ,地球的响应主要表现为弹性地幔中的径向位移 ,且随深度增加急剧减弱 ,负荷阶数越高这种衰减的速度越快 .SNREI地球的地表负荷Love数和体潮Love数与信号频率的依赖关系很弱 .在计算体潮Love数的过程中 ,采用了SNREI地球的运动方程 ,同时考虑了由于地球自转和椭率引起的核幔边界附加压力 ,这一近似处理方法获得的结果能很好地符合地球表面重力潮汐实际观测结果 .Based on the preliminary reference Earth model (PREM), the deformation theory for a spherically stratified and non-rotating Earth with perfectly elastic and isotropic structural relation (SNREI Earth) is employed to investigate the deformation characteristics of the Earth under different forces. The 4 th order Runge-Kutta numerical integration technique is used to solve the equations of the Earth's displacement field. Numerical solutions are obtained for the deformation and gravitational potential perturbation within the Earth interior and on the surface under the surface loads and luni-solar tidal force, and the Love numbers are also calculated. It is shown that the deformation within the solid inner core is very small. The radial variation of displacement at low spherical harmonic degrees (n<10) is relatively complicated within the liquid outer core. While the loading degree is larger than 10, the deformation and the gravitational potential perturbation in both the inner and outer cores, are significantly little. The Earth's response mainly expresses as the radial displacement in the elastic mantle and decreases rapidly with depth. The higher the loading degree is, the more rapidly this response decreases. The frequency-dependence of Love numbers for the surface loads and body tides is very weak for a SNREI Earth. In the computation of Love numbers for the body tides, the motion equations for a SNREI Earth are also adopted; meanwhile, the additional pressure on the core mantle boundary (CMB) is taken into account due to the Earth's rotation and ellipticity. The final results obtained with this approximate procedure are in close agreement with the tidal gravity observations on the Earth surface.

关 键 词：SNREI地球 负荷 引潮力 地球形变 LOVE数 核幔边界附加压力 

分 类 号：P312[天文地球—固体地球物理学]