Global And Regional Geomagnetic Modeling Based On The Ground And CHAMP Satellite Data

The research based on the magnetic data of CHAMP satellite and observation will improve the precision of geomagnetic field model, control the boundary effect of regional magnetic field model, with a great importance on analysis the temporal-spatial distribution of Chinese and its adjacent regions.In this study, we research the global and regional magnetic field modeling based on the magnetic data of CHAMP satellite and observation. We have analyzed the differences of temporal-spatial changes and its secular variation of geomagnetic field over China and its adjacent regions between IGRF12 and IGRF11. Establish the global sphere harmonic model of the geomagnetic field based on the magnetic data of CHAMP satellite and observation, and comparing with IGRF12. Establish the 2D and 3D model over Chinese and its adjacent regions based on CHAMP satellite data and Taylor polynomial method, analysis the difference between 2D model,3D model, IGRF12 and measuring data. Discuss the characteristics and limitations between 2D model and 3D model which based on the magnetic data of CHAMP satellite data and observation.The results are as follows:(1)The difference between IGRF11 and IGRF12 is slight. The distribution of annual change rate of two models is similar. However, because of the measuring data that to create models are different, two models partially differ in local areas. There are obvious differences between measuring data and IGRF12. Geomagnetic secular variation in China by IGRF12 presents linear variation during 2010-2020.(2)The global magnetic field model established by the magnetic data of CHAMP satellite and observation can reflect the global distribution and its secular variation of the geomagnetic field better. Comparing with IGRF12, the overall distribution of global magnetic field described by the model as same as IGRF12, there are some differences in local areas.(3)Results showed RMSE and the mean absolute residuals of each level of the 3D model are about 45% smaller than that of 2D model which established by the magnetic data of CHAMP satellite. RMSE of each level of the 3D model are about 96% smaller than that of 2D model which established by the magnetic data of CHAMP satellite and observation.According to the result can get following conclusion:(1) The global magnetic field model established by the magnetic data of CHAMP satellite and observation can describe the magnetic field over Chinese and its adjacent regions relatively detailed. Reflect Chinese and its adjacent regions in the global distribution of geomagnetic field better. We can see the obvious difference between the model and IGRF12.(2) The quantity of 3D model’s coefficients is about 2 times than 2D model.3D model of low degree can reflect more information. The 3D model of degree 5 basically has the same precision as that of 2D model of degree 8. Geomagnetic distributions and residuals of 3D and 2D models have high consistency.(3)3D model can establish by the data with different altitude, just like the magnetic data of CHAMP satellite and observation. Because of altitude information and its limitations,2D model has certain error, it can’t be better established with the data of different altitude. Therefore,3D model has extensive application value in the modeling based on the magnetic data of different altitude.