Two Dimentional Numerical Simulation Visualization Of Magnetotelluric Forward Sounding

Magnetotelluric (MT) has obtained quite great progress in acquisition system, data processing and interpretation ,and research on basic theory since its naissance in 1950's.Visualization in Scientific Computing is a important studying direction in the fields of numeric calculation of MT. However, the progress of MT Visualization software is rather slow. FEM is used to implement the 2D numeric calculation of MT sounding. We use Delphi language to develop the visual program.In the paper, we first introduce the basic theory of MT sounding. From Maxwell equations, we got the uniform helmholtz equation for transverse eletric and transverse magnetic polarization. In the next part , we introduce the process of FEM in MT numeric stimulation, including magnetotelluric field's border conditions and interpolation, subdivition of FEM. And then ,the Visualization in Scientific Computing in all phases of FEM problems in MT sounding is analyzed and studied. The main contents of this part are as following: the theory of Visualization in Scientific Computing ,the main methods of net dividing of FEM etc. At last , we realize the program with Delphi language and validate the feasibility of the program. There are three major parts of the last chapter:Firstly, the preprocessing visualization of FEM. We develop a model creating module which uses TDrawGrid control to simulate the net dividing of FEM, and we using different colors of the grid cells to denote different resistances thus to realize the visualization of data input.Secondly, the transformation of Fortran to Delphi. We transform the FEM program which was developed by Fortran to Delphi. In order to carry out complex operation , we define a new TComplex class in Delphi.Thirdly, the postprocessing visualization of FEM. We filter out those datas that we need from the results of MT FEM calculation and transfer them to format that Surfer can identify for later graph drawing.