Research On The Correlation Between Ionospheric TEC And Solar Activity Parameters

Ionosphere error,as the most important error source of GPS signal propagation,seriously affects many national defense and national economic departments such as communication,broadcasting,positioning,navigation,radar,measurement,aerospace and electric power.As the main ionization source of the ionosphere,solar activity strongly influences the changes of the global ionosphere.As a part of the earth’s ionosphere,the polar ionosphere shows many irregular features due to the complexity of its magnetic field.Therefore,it is very important to study the main changes of the global ionosphere under the influence of solar activity,as well as the anomalous changes of the polar ionosphere.The main contents of this paper include:(1)Based on the global ionospheric total electronic content(TEC)grid data provided by the World Sunspot Index Data Center of Belgium and CODE Analysis Center of the International GNSS Service(IGS),the relationship between sunspot number and ionospheric TEC is studied by means of mathematical statistics,correlation coefficient and time series.The experimental results show that: The correlation between the two has the property of piecewise change,and the piecewise change is determined by the critical point L of the number of sunspots.Therefore,the piecewise function of the correlation between the number of sunspots and the daily average TEC is determined,and the critical point L of the number of sunspots is given.Changes in the number of sunspots will cause changes in the ionospheric TEC value,and this change has a hysteresis of 1d to 3d,and the daily average ionospheric TEC value lags behind the sunspot number by 2d most obviously.The number of sunspots and the ionospheric TEC value have obvious correlation,but the annual correlation between the number of sunspots and the ionospheric TEC value is uneven.(2)Based on the GPS-TEC and CODE-TEC data in combination with solar activity parameter F10.7 Correlation analysis,time series analysis and spline interpolation methods were used to analyse the influence of solar activity on the polar ionosphere.Moreover,this work included monthly and seasonal changes in different solar activity years,the correlation between polar TEC and F10.7 in various solar activity periods and the temporal and spatial changes of summer and winter solstice in very low solar activity years(2008).The results showed the monthly average value of the polar ionospheric TEC reaches its maximum in May and June under the influence of solar activity.However,the monthly average peak value of TEC may be achieved early during the peak year of solar activity,reaching its maximum value in March or April.The dependence of polar TEC on the solar activity varies in different periods of solar activity(rising or falling period).The correlation between polar TEC and F10.7 was high during the declining period of solar activity.Meanwhile,the correlation between polar TEC and F10.7 significantly decreases during the rising period of solar activity.In the rising period of solar activity,the TEC on different dates will vary under the same solar activity intensity.The overall correlation between TEC and F10.7 in the Antarctic region was low because the low-value TEC has a low correlation with solar activity.The Ionosphere at the Poles was quiet during polar night in 2008.In addition,there will be ionization patch in the Arctic.During the polar day over the Polar region,the ionospheric peak area at the north and south poles occurred in the area with high solar irradiation altitude angle.Howe ver,the ionospheric peak region in the Antarctic area from 10:00 UT to 20:00 UT does not follow this rule.