基于MPI的航空瞬变电磁一维正反演

发布时间：2018-05-30 18:08

本文选题：航空瞬变电磁 + 正演　；参考：《成都理工大学》2015年硕士论文

【摘要】：我国疆域辽阔,地大物博,拥有丰富的资源,但是这些资源大多位于沼泽、沙漠、山地等地形复杂区域。这些区域环境恶劣,给地面电磁法勘探带来了很大的困难。即使在地形较为平坦的地区进行勘探,地面电磁法的效率也较低,很难实现大面积勘探。自从20世纪50年代,航空电磁法获得应用开始,几十年来已经在矿产资源勘查、地下水调查、地质填图等领域获得了广泛的应用。由于航空电磁法的工作方式为空中激发且空中接收,以及其具有较低成本、勘探效率高、可大面积勘探等特点,使得该方法可以克服地面电磁法在复杂地形区域难以施工的困难。和频率域航空电磁法相比,时间域航空电磁法具有较大的勘探深度以及较好的横向分辨率,所以时间域航空电磁法已经称为复杂地形区域勘查的有效工具之一。本文在国家863重大项目“航空地球物理勘查技术与装备”的课题“直升机吊舱式时间域航空电磁勘查系统实用化研究”和地调项目“航空电磁数据处理研究”的支持下,对一维航空瞬变电磁正反演及其并行计算方法进行了研究和分析。具体来说,本文研究内容主要包括以下几个方面:(1)本文从麦克斯韦方程组出发,推导了层状半空间中心回线的正演响应计算公式,并编程实现了一维正演模拟方法。在一维正演方法中,对频时转换问题做了深入分析并对正、余弦变换和G-S变换这三种频时转换对正演响应的影响进行详细的讨论。(2)本文应用阻尼最小二乘法实现了对航空瞬变电磁数据的反演。对反演过程中的阻尼因子选择、雅克比矩阵计算和质量控制指标的设定做了一定的分析,并讨论了典型三层和四层地电模型的反演结果。(3)本文实现了基于MPI(Message Passing Interface)的航空瞬变电磁一维正演和反演方法。首先验证了并行计算的正确性,接着对比了串行和并行计算的耗时问题,最后讨论了不同的多核CPU和不同的进程数情况下并行计算的加速比和并行效率问题。
[Abstract]:Our country has vast territory, abundant land and abundant resources, but most of these resources are located in complex terrain areas such as swamp, desert, mountain and so on. The environment of these areas is very bad, which brings great difficulties to surface electromagnetic exploration. Even if the terrain is flat, the efficiency of surface electromagnetic method is low, so it is difficult to realize large-scale exploration. Since the application of aero-electromagnetic method in 1950s, it has been widely used in the fields of mineral resources exploration, groundwater survey, geological mapping and so on. Because the work mode of aero-electromagnetic method is aerial excitation and aerial receiving, and it has the characteristics of low cost, high exploration efficiency and large area exploration, etc. This method can overcome the difficulty of surface electromagnetic method in complex terrain area. Compared with frequency-domain aero-electromagnetic method, time-domain aero-electromagnetic method has higher exploration depth and better lateral resolution, so time-domain aero-electromagnetic method has become one of the effective tools for the exploration of complex terrain areas. This paper is supported by the project of "Aeronautical Geophysical Prospecting Technology and equipment", "practical Research on Aero-electromagnetic Prospecting system in time Domain of helicopter Pool" and "Research on Aeronautical electromagnetic data processing", which is a major project of national 863 project. In this paper, one-dimensional aeronautical transient electromagnetic forward and inverse modeling and its parallel calculation method are studied and analyzed. Specifically, this paper mainly includes the following aspects: 1) in this paper, the forward response formula of the central loop in layered half-space is derived from Maxwell's equations, and the one-dimensional forward modeling method is realized by programming. In the one-dimensional forward modeling method, the frequency-time conversion problem is deeply analyzed and positive. The effects of cosine transform and G-S transform on forward response are discussed in detail. The selection of damping factor in the inversion process, the calculation of Jacobian matrix and the setting of quality control index are analyzed. The inversion results of typical three-layer and four-layer geoelectric models are discussed. In this paper, the one-dimensional forward modeling and inversion method of aeronautical transient electromagnetism based on MPI(Message Passing interface are realized. First, the correctness of parallel computing is verified, then the time consuming problems of serial and parallel computing are compared. Finally, the speedup and parallel efficiency of parallel computing under different multi-core CPU and different number of processes are discussed.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.326

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