一种基于“移去-恢复”理论的重力数据格网化方法

A gravity gridding method based on"remove-restore"theory

为提升重力数据格网化精度,从频谱组合角度出发,提出了一种基于“移去-恢复”理论的重力数据格网化方法。计算过程中结合地形数据将传统的数学拟合转化为顾及地球物理场信息的物理拟合。这一过程可被简化为“计算-移去-推估-恢复”四步:首先利用高分地形数据计算出目标区域完全布格改正项并利用均衡理论计算出均衡改正;然后将目标区域离散重力数据中的地形相关高频项移除;继而利用频谱更加单一的均衡重力异常进行格网化;最后恢复格网化数据中的地形高频项,得到目标区域格网化的重力数据。实验结果表明,移去地形影响后的重力数据更加平滑,更有利数据格网化;实验区内“移去-恢复”方法精度相比于传统的Kriging格网化精度提升了27.5%,误差阈值更小,分布更加收敛;而且所提出方法构造的局部重力异常能表达出实验区重力场的更多细节特征。

In order to improve the gridding accuracy of gravity data under complex conditions,a kind of gravity data gridding method based on the"remove-recovery"theory from the perspective of spectrum combination is proposed,which combines terrain data to transform traditional mathematical fitting into physical fitting based on earth physical field information.The process can be simply described as"calculate-remove-fit-restore":firstly,the perfect Bouguer correction term of target region is calculated by high-resolution terrain data,and the equalization correction is calculated by equalization theory.Secondly,high frequency terms related to terrain are removed from the discrete gravity data of the target region.Thirdly,the Isostatic gravity anomaly of the target point is gridded by using the Isostatic gravity anomaly of the modeling points.Finally,the Bouguer correction and Isostatic correction of the target points are restored,the Free-air gravity anomaly of the target points are obtained.The experimental results show that the gravity data performs smoother after“remove”the terrain influence,which is more favorable for data-gridding processing.The accuracy of the“remove-restore”method in the experimental area is improved by 27.5%compared with the traditional way.The check difference threshold is smaller and the distribution is more convergent;besides the local gravity anomaly constructed by the proposed method can express more detailed characteristics of the gravity field in the experimental area.