Study Of The Variations Of Ionospheric-plasmaspheric Total Electron Content Derived From Observations And Models At Low Latitude Area

There is a large number of charged particles in the ionosphere and plasmasphere.The radio waves may be reflected or absorbed when they pass through the ionosphere and the plasmasphere.All the technical equipments that depend on radio waves will be affected.With the rapid development of China's space industry,it is particularly important to study the relevant characteristics of the ionosphere and plasmasphere and establish a mature model.Based on the digital altimeter and GPS satellite observation,this paper analyzes the daily variation and seasonal variation characteristics of ionosphere and plasma layer in sanya,China.Using observational data and the data from the IRI model,the IRI model has been analyzed for the ability to predict ionosphere and plasma TEC.First of all,in this paper,the relative characteristics of ionosphere and plasma layer are introduced in detail.The basic methods of studying the total electron content of ionosphere and the total electron content of plasmasphere are described.The research methods used in this paper are expounded in detail.Then,the ionospheric total electron content?ITEC?can be calculated using the observed data derived from the ionosonde.The total electron content from the ground to20,200 km height obtained from GPS observations is defined as GTEC.The difference between GTEC and ITEC can be considered as the plasmaspheric total electron content?PTEC?.Combined with the ionosonde and GPS observations,the data from GPS and ionosonde at Sanya station?18.34°N,109.62°E?in 2012 was selected to study the variations of PTEC.The results show that the variations of GTEC are the same as that of ITEC.Both PTEC and the relative contribution of PTEC?to GTEC?exhibited obvious diurnal variations.The PTEC was in the range of 3-22 TECU(1 TECU=10¹⁶el/m²),the PTEC maximum appeared at about the local time of the sunset,and the minimum appeared around the sunrise.The contributions of PTEC were generally about40%at night,even up to 80%,while the values during the daytime were generally less than 20%.Finally,the total electron content of the ionosphere and the plasmasphere was calculated using the IRI model.The IRI predicted value and measured value of ionospheric total electron content were compared and the results showed that the R-square between the two was 0.88,both the overall trend and the specific value had good consistency,and the ionospheric TEC calculated from IRI model is less than the measured value.It is effective to forecast the total electronic content of short-term ionosphere by the IRI model.The IRI model can effectively eliminate the influence of the total electron content of the ionosphere during periods of calm.In this paper,the IRI predicted values and measured values of the plasmasphere are also compared.The results show that the difference between the two can reach up to 90%.It will cause a large error using the IRI model to predict the total electron content of the plasma layer.