Effects of filtering solar activity from noon and midnight hmF2 to assess long-term variability

JOSE V. VENCHIARUTTI; ANA G. ELIAS; BLAS F. DE HARO BARBAS; MARTA ZOSSI DE ARTIGAS

Sunny Beach

Workshop; 7th Workshop: Solar Influences on the Magnetosphere, Ionosphere and Atmosphere; 2015

Space Research and Technology Institute, Bulgarian Academy of Sciences

Long-term variations and trends in the ionosphere are linked mainly to the increase in greenhouse gases concentration, but also to natural causes such as solar and geomagnetic activity long-term changes and secular variations in the Earth magnetic field. In order to analyze ionospheric trends and determine the proper role of each extrernal forcing, solar activity effect must be filtered out first since around 90% of ionosphere parameters variance is due to solar variations. In this work, the effects of filtering solar activity from hmF2 at 12 LT and 0 LT are analyzed comparatively through the effects on long-term trend calculation, considering that the behavior of the daytime ionosphere is strongly controlled by solar radiation, while nighttime ionosphere is controlled mainly by recombination processes and ionospheric dynamics.