Two Swarm satellite magnetic field data earthquake precursor anomaly extraction method based on principal component analysis

Abstract

The invention relates to a two Swarm satellite magnetic field data earthquake precursor anomaly extraction method based on principal component analysis. The method comprises the following steps: reading magnetic field Y component data of a satellite Swarm A and a satellite Swarm C, and removing incorrect data according to flag bits Flags_B of the data; selecting a study time range and a study areaaccording to an earthquake; selecting orbital data obtained when local times of the satellite Swarm A and the satellite Swarm C are night times; removing effects of the main geomagnetic field throughan IGRF model; projecting the original data on a group of new spatial orthogonal bases through the principal component analysis on the magnetic field Y component data of the satellite Swarm A and thesatellite Swarm C, so that principal components, of which the variances are arranged in a descending order, are obtained; finding out the components with high geomagnetic activity relevance through comparison between the principle components and geomagnetic indices, removing the components with the high geomagnetic activity relevance, and only analyzing the remaining principal components; and carrying out anomaly extraction on the remaining principal components through a skewness and kurtosis coefficient defined by skewness and kurtosis, so that earthquake precursor anomalies can be extracted. The method provided by the invention has the advantages that geomagnetic activity interference can be removed, so that the earthquake precursor anomalies can be accurately extracted.

Description

technical field [0001] The invention relates to the field of ionospheric magnetic field earthquake precursor anomaly extraction, in particular to a principal component analysis-based method for extracting earthquake precursor anomaly from Swarm double star magnetic field data. Background technique [0002] There is growing evidence that electromagnetic phenomena can be used to make short-term predictions of large earthquakes. In addition to the study of ground electromagnetic phenomena, based on the LAIC (Lithospheric-Atmospheric-Ionospheric Coupling Lithosphere-Atmosphere-Ionosphere) mechanism, the study of seismic ionospheric anomalies relies on the development of satellites and has become a direction of earthquake precursor anomalies. The DEMETER satellite is the first satellite dedicated to monitoring earthquake-related signals. A large number of scholars have analyzed various parameters measured by DEMETER satellite loads, such as electron density, ion density / temperat...

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a method for extracting earthquake precursor anomalies based on principal component analysis of Swarm double star magnetic field data, making full use of the characteristics that Swarm A and C stars fly side by side and have almost the same orbital height, and apply principal component analysis to The magnetic field data of the Y components of the two stars are separated, and after removing the interference of the geomagnetic activity, the abnormality is extracted by using the skewness and kurtosis, which makes up for the abnormal results of the analysis of a single satellite or just the data of multiple satellites in the above technology Combining the analysis, and only analyzing the data of the static magnetic time period, cannot make full use of the advantages of the two satellites A and C of the Swarm satellite flying almost side by side and measuring the magnetic field at the same time.

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