Inversion Of Mantle Conductivity Based On Swarm Satellite Measurement Data

Rock conductivity is one of the important physical parameters that reveal the internal state of the earth.It is sensitive to the presence of temperature,pore fluid,melting and volatile components in the Earth,and their volume and content,and the mantle conductivity also reflects the mantle,Such as graphite,fluid,partial melt,etc.,and its research can also provide complementary information for global seismic tomography.In this paper,the latest research progress in this field is introduced,and three methods of time domain,frequency domain and C inversion of mantle conductivity using satellite measurement data are presented.The time domain inversion method is analyzed emphatically.The mathematical relationship between the conductivity and the changing magnetic field is found,and then the differential equation is numerically satisfied to satisfy the accurate result in the case of discontinuous input.Combined with the external magnetic field of the Earth's external magnetic field measured by Swarm satellite and The first-order harmonic coefficient model of the internal induced magnetic field is divided into the number of layers to be solved,and the conductivity of each layer is obtained.Finally,a series of steps such as conductivity and depth are combined to invert the mantle Dimensional conductivity.The inversion results are compared with a series of models such as ak135,Brunn,ESA one-dimensional conductivity reference model,and the conductivity is gradually increased from the surface to the center,and the temperature has the greatest influence on its change.And the Earth's internal pressure changes and other conclusions.Comparing with the Earth model of Bren 1,it is found that there may be liquid fluid at the bottom of the upper mantle.At the same time,the conductivity model is compared with the ak135 model,and the change of conductivity is consistent with the change of S wave velocity,which shows that the influence factors of conductivity S wave velocity changes in some of the factors.Compared with the one-dimensional conductivity model obtained by ESA,Constable&constable,Olsen and Kuvshinov,the model is superior to the latter in terms of accuracy,reliability and depth of exploration.Before 1000km,the model has high reliability,The reason why the conductivity is abnormally undulating is unknown.At the end of this paper,we compare the three-dimensional conductivity model of mantle in Puti and Velimsky in frequency domain and time domain respectively.It is found that the mantle conductivity has higher accuracy and deeper inversion accuracy in the time domain,Inversion of mantle conductivity is a successful and reliable method of research.