(1. 中国科学技术大学 地球和空间科学学院，合肥 230026；
2. 中国地质科学院地球物理地球化学勘查研究所，自然资源部地球物理电磁法探测技术重点实验室，廊坊 065000；
3. 中国科学技术大学 蒙城地球物理国家野外科学观测研究站，蒙城 233500)
摘 要: 磁性异常对时间域航空电磁观测数据有明显影响，但关于同时存在电导率和磁导率异常的时域航空电磁三维正演模拟的工作还未见报道。本文发展了考虑磁化效应的频率域电磁三维矢量有限元数值模拟技术，在此基础上，利用时-频转换实现同时考虑地下电导率和磁导率异常的三维时间域航空电磁正演计算，理论模型验证了该算法的准确性和稳定性。结果表明：磁化异常显著增强了时间域航空电磁响应强度，特别是在强磁性环境背景下，时间域航空电磁的响应值在良导体中反而比在高阻体中更小，这个新现象对具有潜在异常磁导率地区的时间域航空电磁数据解释及其应用有重要影响。
关键字: 时间域航空电磁法；磁导率；矢量有限元；数值模拟
（1.School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
2.Key Laboratory of Geophysical Electromagnetic Probing Technologies of Ministry of Natural Resources, Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Science, Langfang 065000, China;
3. Mengcheng Geophysical Field Observation and Experiment Station, Mengcheng 233500, China）
Abstract:Magnetic anomalies have a significant impact on the time-domain airborne electromagnetic observation data, while the work of 3D forward modeling of time domain airborne electromagnetic with conductivity and permeability anomalies has not been reported. In this paper, the three-dimensional vector finite element numerical simulation technology in the frequency domain considering the magnetization effect was developed. On this basis, the three-dimensional airborne electromagnetic forward calculation in time domain considering both the underground conductivity and the permeability anomaly was realized by using the time-frequency conversion. The theoretical model verified the accuracy and stability of the algorithm. Further three-dimensional numerical simulation results show that the magnetization anomaly significantly enhances the time-domain airborne electromagnetic response strength, especially in the strong magnetic environment, the response value of time-domain airborne electromagnetic is smaller in the good conductor than in the high resistance body. This new phenomenon has an important impact on the interpretation and application of time-domain airborne electromagnetic data in areas with potential abnormal permeability.
Key words: time-domain airborne electromagnetic method; permeability; vector finite element; numerical simulation
