Extending the analysis on the best solar activity proxy for long-term ionospheric investigations

BRUNO ZOSSI; FRANCO MEDINA; GLORIA TAN JUN; JAN LASTOVICKA; TRINIDAD DURAN; MARIANO FAGRE; BLAS F. DE HARO BARBAS; ANA G. ELIAS

PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES

ROYAL SOC

Lugar: Londres; Año: 2023

1364-5021

Based on a previous study to select the best solar activity proxy for ionospheric parameters modeling, we expand the analysis to include 24-hour time span, increase the spatial coverage by considering additional ionospheric stations, and update the analysis to 2021. Annual means of foF2 are analyzed for 12 selected stations from Europe, Asia, and Oceania, with high-quality data covering the period 1978-2021 in most of the cases, including two of the three European stations of the previous study. The same four solar proxies were used: F10.7, F30, Mg II, and He II, which, based on the high linear correlation between each of them and foF2, serve to model this ionospheric parameter through a linear regression. The results of our comparative analysis, extended to more stations, all the hours and updated time series, agree with previous works, being Mg II and F30 the best solar proxies for foF2 modeling, while He II is found to be the least effective for this purpose. The importance of the solar proxy selection to model foF2 for filtering purposes to later estimate long term trends, is highlighted considering that different solar proxies applied might result in somewhat different foF2 long-term trend values.