中文摘要：

为提高复杂条件下时间域航空电磁数据解释精度，本文开展了时间域航空电磁三维并行反演算法研究。该算法中的三维正演是基于有限差分技术，并采用“移动脚印”技术来减小实际计算模型尺寸；三维反演基于Gauss—Newton反演方法，并采用显式灵敏度矩阵计算技术减少反演过程中的正演次数。为提高三维反演的效率，本文基于OpenMP并行库实现了三维反演的并行化。从理论和实测数据的三维并行反演结果可以看出本文的并行化策略明显地提高了三维反演的速度，能够胜任大数据量时间域航空电磁实测资料三维反演解释任务。

英文摘要：

To improve the inversion accuracy of time-domain airborne electromagnetic data, we propose a parallel 3D inversion algorithm for airborne EM data based on the direct Gauss-Newton optimization. Forward modeling is performed in the frequency domain based on the scattered secondary electrical field. Then, the inverse Fourier transform and convolution of the transmitting waveform are used to calculate the EM responses and the sensitivity matrix in the time domain for arbitrary transmitting waves. To optimize the computational time and memory requirements, we use the EM ＂footprint＂ concept to reduce the model size and obtain the sparse sensitivity matrix. To improve the 3D inversion, we use the OpenMP library and parallel computing. We test the proposed 3D parallel inversion code using two synthetic datasets and a field dataset. The time-domain airborne EM inversion results suggest that the proposed algorithm is effective, efficient, and practical.