Three-dimensional conjugate gradient inversion of magnetotelluric sounding data  

大地电磁法三维共轭梯度反演研究(英文)

作　　者：林昌洪[1] 谭捍东[1] 佟拓[1] 

机构地区：[1]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《Applied Geophysics》2008年第4期314-321,共8页应用地球物理（英文版）

基　　金：sponsored by National Natural Science Foundation of China (Grant Nos. 40774029, 40674037, and 40374024);the National Hi-tech Research and Development Program of China (863 Program) (No. 2007AA09Z310);the Program for New Century Excellent Talents in University (NCET).

摘　　要：Based on the analysis of the conjugate gradient algorithm, we implement a threedimensional （3D） conjugate gradient inversion algorithm with magnetotelluric impedance data. During the inversion process, the 3D conjugate gradient inversion algorithm doesn＇ t need to compute and store the Jacobian matrix but directly updates the model from the computation of the Jacobian matrix. Requiring only one forward and four pseudo-forward modeling applications per frequency to produce the model update at each iteration, this algorithm efficiently reduces the computation of the inversion. From a trial inversion with synthetic magnetotelluric data, the validity and stability of the 3D conjugate gradient inversion algorithm is verified.在对共轭梯度算法深入分析的基础上,我们实现了大地电磁阻抗资料三维共轭梯度反演算法。三维共轭梯度反演算法的特点是反演过程中不需要实际计算和存储雅可比矩阵,只需要计算雅可比矩阵的转置与一个向量的乘积以及雅可比矩阵与另一个向量的乘积,直接可以得到模型修正量。三维共轭梯度反演算法每进行一次模型参数更新迭代只需要1次正演和4次"拟正演",有效的减少了反演的计算量。通过对理论模型合成数据进行反演试算,验证了所实现的大地电磁三维共轭梯度反演算法的有效性和稳定性。

关 键 词：MAGNETOTELLURIC 3D INVERSION conjugate gradient 

分 类 号：P631.325[天文地球—地质矿产勘探]