(1. 中國科學(xué)技術(shù)大學(xué) 地球和空間科學(xué)學(xué)院，合肥 230026；
2. 中國地質(zhì)科學(xué)院地球物理地球化學(xué)勘查研究所，自然資源部地球物理電磁法探測技術(shù)重點(diǎn)實(shí)驗(yàn)室，廊坊 065000；
3. 中國科學(xué)技術(shù)大學(xué) 蒙城地球物理國家野外科學(xué)觀測研究站，蒙城 233500)
摘 要: 磁性異常對時(shí)間域航空電磁觀測數(shù)據(jù)有明顯影響，但關(guān)于同時(shí)存在電導(dǎo)率和磁導(dǎo)率異常的時(shí)域航空電磁三維正演模擬的工作還未見報(bào)道。本文發(fā)展了考慮磁化效應(yīng)的頻率域電磁三維矢量有限元數(shù)值模擬技術(shù)，在此基礎(chǔ)上，利用時(shí)-頻轉(zhuǎn)換實(shí)現(xiàn)同時(shí)考慮地下電導(dǎo)率和磁導(dǎo)率異常的三維時(shí)間域航空電磁正演計(jì)算，理論模型驗(yàn)證了該算法的準(zhǔn)確性和穩(wěn)定性。結(jié)果表明：磁化異常顯著增強(qiáng)了時(shí)間域航空電磁響應(yīng)強(qiáng)度，特別是在強(qiáng)磁性環(huán)境背景下，時(shí)間域航空電磁的響應(yīng)值在良導(dǎo)體中反而比在高阻體中更小，這個(gè)新現(xiàn)象對具有潛在異常磁導(dǎo)率地區(qū)的時(shí)間域航空電磁數(shù)據(jù)解釋及其應(yīng)用有重要影響。
關(guān)鍵字: 時(shí)間域航空電磁法；磁導(dǎo)率；矢量有限元；數(shù)值模擬
（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
