摘要
The authors present a new approach for downward continuation of potential fields: a derivative-iteration method in the case of that downward continuation is an unstable problem. From the definition of vertical first-order derivatives, the authors connect the values of the potential fields of observation planes with the values of the planes of upward continuation in a certain height and downward continuation in the same height. The authors use also the iterative method to successive approximation. Thus the authors deduce the recursive formula of the derivative-iteration method for continuation downward of potential fields in space domain. Taking the complexity of achieving upward continuation integral equations in spatial domain into accout, the fast Fourier transform is adopted in the recurrence formula. Then, it gets the derivative iteration formula in wavenumber domain.