摘要
在瞬变电磁法正演计算中,常常需要频时转换来获得垂直磁场随时间的变化率。目前已经提出了多种频时转换方法,其中G-S变换法只涉及实数计算,具有较快的速度,因此已经成为航空瞬变电磁正演模拟的候选方法。由于航空瞬变电磁数据巨大,时间数较多,因此在保证精度的条件下怎样提高计算速度成为当前亟待解决的问题。鉴于大量频点的正弦变换和余弦变换具有较高的精度,这里使用三层和四层典型地电模型,通过比较余弦变换、正弦变换和不同点数G-S变换的正演计算结果来确定最佳的G-S变换系数。实验结果比较和分析认为,采用8个系数的G-S变换法不仅有较快的计算速度,而且也有较高的计算精度。
The change rates of vertical magnetic field with time are usually obtained by the frequency- time conversion method in transient electromagnetic modeling.At present,despite many kinds of frequency- time conversion methods have been proposed,the G-S transform with faster computation speed has become an important candidate for airborne transient e-lectromagnetic method.Due to the huge data and the long time of airborne electromagnetic method,how to improve the compu-tation speed of modeling under the certain accuracy becomes a key problem to be solved.Due to the higher frequency- time conversion precision of sine and cosine transform with the larger number of frequency coefficients,this paper may determine the best coefficients of G-S transform by the comparison of the forward modeling results of sine transform,cosine transform and G-S transform with different frequency based on the three-layer and four-layer model.By comparison and analysis of the experimental results,this paper shows that the G-S transform with 8 coefficients not only has faster speed,but also a high degree of accuracy.
出处
《物探化探计算技术》
CAS
CSCD
2015年第6期671-679,共9页
Computing Techniques For Geophysical and Geochemical Exploration
基金
贵州省科学技术基金([2013]2297)
关键词
航空瞬变电磁法
G-S变换
正弦变换
余弦变换
airborne transient electromagnetic
G-S transform
sine transform
cosine transform
