Study On Characteristic Of Geomagnetic Pulsation And Geomagnetic Storm In Meridian Region

Meridian chain project (called the Meridian Space Weather Monitoring Project) is the first major fundamental project guided by the space science of China. This project continuously observe the space environment parameters from about20,30km above the ground to the senior atmosphere, the ionosphere,the magnetic layer and the interplanetary space about several distance of the earth’s radius by using15observation stations along the120°E and30°E.The position of meridian region is special. because of the existence of the geomagnetic field who plays an important role in particle and plasma movement, current system and magnetic layer, the ionosphere structure, and the zenith angle effect of the electromagnetic radiation of the sun,causes huge change in space environment along the meridian region. Therefore, our research about the geomagnetic pulsation and storm in meridian region is very meaningful to understand the knowledge of the rule of disaster space weather change and the whole disturbance of solar wind-magnetosphere-ionosphere interaction, also play an important role in identifying earthquake electromagnetic precursor information from earthquake anomaly.We have a lot of instruments, especially the using of the high sampling rate, wide frequency band, high precision inductive magnetometer, which can provide high accuracy data. This paper use data from fluxgate and inductive magnetometer to analysis the character of geomagnetic pulsation and storm.For the research of the geomagnetic pulsation, this paper first introduced the history of the research about the geomagnetic pulsation and the difference of different types of pulsation. and then the instrument capability, system structure and working principle of these two magnetic instruments were presented. and next briefly stated the research area and the data which we used.we also introduced the methods used for the extraction of geomagnetic pulsation, the empirical mode decomposition(EMD) approach which used to get the geomagnetic pulsation from quite data and storm data. by comparing with the traditional wavelet method, we found out that the EMD didn’t need to choose base function, but the results of wavelet decomposition depended on the choice of wavelet function, EMD could adaptively decompose the original signal into a series of linear, smooth IMFs, and each IMF was an approximate signal with nearly single frequency components, but the whole Hilbert transformation till now was short of strict mathematical proof, which was also one of its big disadvantages. The next part of this paper we discussed the amplitude, frequency of geomagnetic pulsation which recorded by these two instruments, analyzed the amplitude of Z component in different instrument, got correlation coefficient in fluxgate differential data and inductive magnetometer one second data, and discussed the reason of their low coefficient and analyzed their latitude effect along longitude120°E meridional chain and their characters along30°N parallels chain. From the result, the amplitude of geomagnetic pulsation was relate to the latitude, the main frequency in each station was nearly the same, and the magnitude of the main frequency became small with decreasing latitude and the conclusions from these two kind of instruments were similar.In research of the magnetic storms, we firstly gave the development of magnetic storms and their different types in the theory section of this paper, gave the normal shape of H and Z component of fluxgate magnetometer and the form of storm shape in the beginning of inductive magnetometer, analyzed the reason why the two instruments response different at the beginning of geomagnetic storm and their frequency spectrum difference. Then by using different methods to analysis fluxgate magnetometer data sets, and comparing with the data sets of induction magnetometer, we got the conclusion that their correlation coefficient in H component was very large, which was consistent with the different of their working principle, and in Z component was very small caused by their different installation method,Z component response was not huge. In the end we analyzed one geomagnetic storm, gave it’s whole process from the ionosphere to the ground station, studied the latitude effect, and the result showed that the biggest amplitude of fluxgate magnetometers became large with the increasing of the latitude, the same whit the induction magnetometers, the result of fluxgate magnetometers was very well consistent with the result of former researchers.