用逐段多项式法反演重力资料

逐段多项式法是一种新的反演重力资料的方法。它基于这样的假定:已知单一密度界面的平均埋藏深度,此界面的密度差是分段均匀的,因此,可用 M阶多项式逐段逼近各个区间内界面的起伏。在逐段逼近界面形态过程中,有时在各区间交接处会出现不连续现象,为此采用正、反向计算结果的平均值作为界面反演求得的埋藏深度。由反演结果求得的重力异常与实际的重力异常差异太大时,可根据它们之间的残差再进行计算,修正界面深度值,以逐步逼近真实界面。本方法兼顾了压缩质面法和多项式法两者的长处,无论对平缓的界面还是起伏频繁的界面反演,都显示了一定的优越性。压缩质面法和多项式法可视为逐段多项式法的两个特例。

Gravity data inversion by sectioned polynomials

Se;.tioned polynomial is a new method for gravity data roversi on.It is based on the assumption that the mean depth of a density boundary is known and the density contrast is sectionally uniform.Hence,the undulation of the boundary in each section can be approximated by a polynorrrial of degree 14I,then the bcandary surface is discontinuous in sectionally app=oxira:ating the boundary,the mean of the computations obtained forward and inverse directions can be considered as the depth con?puted by inversion..lhen there is too great difference between tile gravity anomalyobtained by inversion and the observe ore, then on the basis of the residual error,computation can be ccrtir Pd to modify computed depth until it approaches the real depth.This method has the merits of both compressed mass plane method and the polynomial method.Its merits are shown in he inversionsof both gentlely undulating boundary and frequently undulating one.The methods of compressed mass plane and polynomial may beeon siderd as two special cases of the sectioned polynomial method.