月球水准面异常和表面地形变化是其内部密度不均匀和各个界面的起伏变化的体现,因此利用水准面和地形之比(geoidto to pography ratio,GTR)可估计月球均衡和月壳厚度。本文基于月球重力场模型SGMIOOh和地形模型STM359-grid-02,经过去除表面玄武岩填充和深层异常质量影响,并结合理论Airy均衡模型中GTR与参考月壳厚度的关系,计算得到了新的月壳厚度模型。该模型的月壳平均厚度为36.9km,背面比正面平均厚约13.5km,Apoll012/14登陆点的月壳厚度分别是28.3km和29.1km。在各月海盆地存在着中央较薄、四周逐渐增厚的趋势。
Lunar geoid (or selenoid) anomaly and topogrphy variations are the expressions of its internal density anomaly and boundary undulations. So the geoid to topography ratio (GTR) can be used to study the isostatic state of the moon and its crustal thickness. A new lunar crustal thickness model was derived by GTR technique from filtered gravity model SGM100h and topography model STM359_grid-02, with the mare fill and subcrustal mass anomalies removed. This model indicates that the lunar crust has an average thickness of 36. 9 km, and the average farside thickness is 13. 5 km thicker than nearside. The crustal thicknesses at Apollo 12/14 sites of our crustal thickness model are 28.3km and 29.1km, respectively. It also shows that the crust beneath the mare basins is generally thinner than the regions around,