Method for estimation of solar, geomagnetic, and atmospheric contributions to 27-day component of peak electron density

Abstract

The study suggests a new method for estimation of the solar, geomagnetic, and atmospheric contributions to 27-day component of peak electron density. For our analysis, we calculated complex amplitudes of 27-day components filtered from the data sets of peak electron density and indices of solar and geomagnetic activity. The use of complex amplitudes takes into account both the amplitude ratios and phase shifts (time delays between the 27-day components) within linear regressions. In this study we use the coefficients of determination for linear regressions to estimate the solar and geomagnetic contributions to the ionospheric variations. The coefficient of determination represents the proportion of the total variation in the dependent variable (ionospheric variations) that is explained by the independent variables (variations in solar and geomagnetic indices). Comparison with other studies showed that, apparently, the contribution estimation strongly depends on the filter bandwidth and the method for calculating the correlation coefficient. The choice of the optimal method and the filter bandwidth is open to question. Keywords: Ionosphere, 27-day component, Solar and geomagnetic activity