位场曲化平的插值-迭代法  

The interpolation-iteration method for potential field continuation from undulating surface to plane

作　　者：徐世浙[1] 余海龙[1] 

机构地区：[1]浙江大学地球科学系,杭州310027

出　　处：《地球物理学报》2007年第6期1811-1815,共5页Chinese Journal of Geophysics

基　　金：教育部博士点基金项目(20050335090);国家自然科学基金项目(40774059);国家863计划项目(2006AA06Z107)资助

摘　　要：将起伏曲面B上的位场向下延拓至曲面最低点的平面A的插值-迭代法步骤是:1)将曲面B上的场值放置在水平面A上具有相同水平坐标的点上,作为A上的初值;2)用若干水平面切割B,从A的初值,用快速傅里叶变换法(FFT)向上延拓出这些平面的场值,用插值的方法从这些平面的场值计算曲面B的场值;3)根据B上的实测值与计算值的差值,对A上的值进行加权改正;4)重复步骤2)和3),直到B上的差值小到可以忽略.这种插值-迭代法具有高的计算速度,比通常的FFT法延拓得更深,可以超过10倍点距.文中给出计算实例.The interpolation-iteration procedure of downward continuation from the undulating surtace B to me horizontal plane A that below the lowest point of B is： （1） choose the initial potential field value at each point on the plane A as the observed one on the surface B at the point with the same horizontal coordinates; （2） intersect the surface B with several planes and obtain the field values on these planes by upward continuing the fields on A using the FFT technique, then the fields on the surface B can be interpolated from the fields on these planes; （3） the new field values on A are then obtained by adding the initial values and the weighted difference between the observed and the calculated field values on B; （4） repeat steps （2） and （3） until the difference becomes negligible. The interpolation-iterative continuation method possesses a higher computation speed and can stably downward continue data to a much deeper depth than using standard FFT techniques, up a depth equal to more than 10 times the grid interval. A test example for real survey data is given.

关 键 词：位场 向下延拓 插值 迭代 FFT 磁异常 

分 类 号：P631[天文地球—地质矿产勘探]