重力与磁力测量数据向下延拓中最优正则化参数确定方法

Optimal Regularization Parameter Determination Method in Downward Continuation of Gravimetric and Geomagnetic Data

根据观测面和延拓面测量数据的Poisson积分平面近似关系,结合快速傅里叶变换算法,将其转换到频率域进行计算,提高了计算速度。同时,为了克服计算的不稳定性并进一步提高计算精度,引入Landweber正则化迭代法,并在此基础上采用L曲线法研究了最优正则化参数的确定。最后,采用模型磁测数据验证了L曲线法在确定磁场反演正则化参数时的有效性,取得了较好的延拓结果。

Downward continuation is one of the key steps in the processing of gravimetric and geomagnetic data.However,downward continuation is a typical ill-posed problem,and its computation is unstable.Therefore,the regularization methods are needed in order to realize the effective continuation of gravimetric and geomagnetic data,and the determination of regularization parameter is the most important content in the study of downward continuation by regularization method.According to the Poisson integral plane approximate relationship between observation and continuation data,and combining with fast Fourier transform(FFT)algorithm,the computation formulae were transformed to frequency domain so as to accelerate the computational speed.The Landweber regularization iteration method was introduced so that the instability could be overcome and the results precision could be improved,based on that the determination method of optimal regularization parameter in downward continuation was studied by L-curve method.The availability of regularization parameter was validated by simulated geomagnetic data,and continuation results in good precision were also derived.