Analysis of characteristics of time series variation in electromagnetic satellite data before strong-moderate earthquakes

The electromagnetic satellite data have a strong time background tendency of dynamic variation for a region, which will bring about difficulty to the identification of earthquake precursory anomaly, and the other conventional statistical methods eliminating background trend are difficult to obtain satisfactory results. Based on the data observed by the French electromagnetic satellite, the time series like the electron temperature and concentration are calculated and their characteristics are analyzed according to certain rules of time and space about the running orbits of the electromagnetic satellite, then, an effective method of Chebyshev quantitative model is proposed based on many tests to eliminate the background trend of the time series variations of electromagnetic satellite observation data, and at the same time, the evolution characteristics of the electron temperature and concentration parameters before strong-moderate earthquakes are studied to obtain the relationship between the two. Finally, some key issues are discussed preliminarily to provide the foundation for quantitative processing and system analysis of the electromagnetic satellite observation data in the future.