Statistical Analysis Of Solar Flares During 22,23 And 24 Solar Cycles

This paper has analyzed the number,proportion,monthly average number,X-ray flux and Extreme ultraviolet radiation flux,duration,location of slar flares and ionospheric response to solar flares using the solar flare events observerd during the22 nd,23rd and 24 th solar cycles.Statistical analysis showed that:(1)The total occurrence rates of M and X class flares are 10.33%,6.77%,and5.45% in SCs 22,23,and 24,respectively,which indicates that the SC 22 is an SC with frequent large flares.Moreover,the temporal variations of the number of flares,solar F10.7,X-ray flux and Extreme ultraviolet flux in three SCs indicate that the solar activity intensity of the SC has declined since SC 22.(2)There is a good positive correlation between the annual number of flares and the annual mean of solar F10.7 index,the annual mean of X-ray flux and Extreme ultraviolet flux.The correlation coefficient between annual number of flares and solar F10.7 index is higher than that between annual number of flares and X-ray and EUV flux.In addition,The linear correlation between the annual number of flares and three solar activity parameters in SC 24 is greater than that in SCs 22 and 23.(3)The duration of flares in SC 22 is obviously longer than that in SCs 23 and 24,which is because solar activity is much higher in SC 22 than in SCs 23 and 24.The duration of flares increases with the increase of flare intensity and the duration of class X flares in the three solar solar cyclesis 7.15,2.65 and 2.40 times that of class B flares,respectively.(4)The results of the study about the flare location on solar disk show that all the flares are mainly distributed in the solar latitude-40°?40° and most prolific in the10–15° latitude band.The distribution of flares in the northern and southern hemispheres gradually moves toward the center on the solar disk with the increase of SC.The north–south(N–S)asymmetry is significant in the all three SCs and peaks at the north and south latitude belt of 10–15°,and the southern hemisphere is dominant in the N–S asymmetry during three SCs.(5)We calculated the ionospheric solar flare activity indicator during solar flares from 1996 to 2008 using GPS data,and then used partial correlation analysis to analyze the relationship between the ionospheric solar flare activity indicator and solar flare parameters.The study found there is a strong correlation between ionospheric solar flare activity indicator and the solar flare class,location,duration,rise time,and X-ray and Extreme ultraviolet radiation fluxes of different bands.Training the BP neural network model of the characterization index peak with these factors.The prediction results of the training model show that the correlation coefficient of the predicted value and the true value reaches 0.9.