Research On Antarctic Ionospheric Characteristics Under Geomagnetic Storms Based On GPS Technology

The existence of coupling between the ionosphere and the magnetosphere and the middle and high levels of the atmosphere is the link between the near-ground space and the solar-terrestrial space,which is closely related to the human space activity.Therefore,the study of the ionosphere has a very important scientific significance.Ionosphere will lead to the degradation of radio signal quality,navigation and positioning accuracy,space-based radar system imaging quality deterioration,while the ionosphere in major natural disasters(such as typhoons,tsunamis,earthquakes,volcanic eruptions,etc.)The process shows a certain degree of abnormality,so ionospheric research also has a very important application value.The ionosphere is directly connected with the magnetosphere and interplanetary space,and the physical form and mechanism are different from those in the middle and low latitudes.It plays an important role in the related research of space physics.The change of the ionosphere in the polar region is very complicated.A variety of ionospheric processes and multiple spatial phenomena often occur at the same time.These changes can directly or indirectly affect the ionosphere in the middle and low latitudes,and even the solar environment,so the polar ionosphere The study also has a very high reference value for the global ionosphere.Due to solar activity and other factors caused by magnetic storms will lead to abnormal disturbance of the ionosphere,the communication system,spacecraft,navigation and positioning accuracy caused serious impact.The disturbance of the magnetic storm to the ionosphere at different geographical locations,local times,seasonal disturbances occur,and are affected by the magnetic storm level.The characteristics and physical mechanism of the magnetic storm on the ionospheric disturbance are still not completely solved.By analyzing the characteristics of the magnetic field response of the polar region,the coupling relationship between the magnetic layer and the ionosphere can be further explored.In this paper,the ionospheric response of the Antarctic ionosphere is analyzed on the basis of the spherical harmonic function.Based on the GPS data of IGS(International GNSS Service),POLENET(The Polar Earth Observing Network)and CACSM(Chinese Antarctic Center of Surveying and Mapping),this paper systematically studies the GPS data of Antarctic ionospheric TEC using GPS technology.The TEC of the Antarctic ionosphere was extracted by spherical cap harmonic analysis,and the temporal and spatial distribution characteristics were analyzed.The ionospheric response during the magnetic storm was analyzed briefly.The main research contents include:1,The present situation and development of ionospheric detection and research are introduced according to the research status at home and abroad.The principle and method of ionospheric inversion based on GPS technology are introduced.The detection and repair of the cycle jump,the elimination of the gross error and the solution of the hardware delay are analyzed in the calculation of the high precision ionospheric TEC.This paper mainly introduces the method of establishing the TEC model of Antarctic ionosphere.2,The model is used to model the solar activity in 2009 and the data of solar activity in 2012.The basis function of the spherical cap function has the orthogonality in the region.The zero order term of the coefficient of the spherical cap harmonic function can reflect the average content of the ionospheric TEC value in the region,and the zero order term coefficient of the spherical cap harmonic function TEC daily mean found that the two have a strong correlation,the correlation coefficient of 0.97 or more,to verify the ball crown harmonic model has the physical meaning,and its spectral characteristics were analyzed.This paper discusses the seasonal variation of the TEC in the Antarctic region and the local geochemical location,and finds out the anomalous anomalies of the Weidel Sea in the Antarctic region,and gives a brief summary of its performance characteristics.3,The response characteristics of the ionosphere during the geomagnetic storms in October 2012 were analyzed by the spherical cap harmonic model.The daily mean value of the ionosphere during the geomagnetic storm was positively correlated with the geomagnetic index,especially at the time of the two magnetic storms,TEC Values were significantly decreased,indicating that the ionospheric violence for the negative phase of violence.The VTEC distribution of the ionosphere every 2 hours in the whole Antarctic region was calculated and analyzed by the spherical cap harmonic model.The analysis shows that the TEC value decreases further after 08:00 UT over time in the whole Antarctic range.And the night and side are descending.In the higher latitudes,the TEC decline is more obvious,indicating that the ionospheric negative phase ripple appears in the whole Antarctic region.