Effects of volcanic eruptions over the ionosphere based on hourly records

ARGELIA H. C. DE RAGONE; ANA G. ELIAS; MARTA ZOSSI DE ARTIGAS; AMALIA N. F. DE MANZANO

Rosario

Congreso; XXI Reunión Científica de la Asociación Argentina de Geofísicos y Geodestas; 2002

AAGG, Asociación Argentina de Geofísicos y Geodestas

Other authors studies, based on 1-minute interval sounding, have detected ionospheric disturbances characterized by quasi-periodic wavelike trains of periods around 16 to 30 minutes as consequence of strong volcanic eruptions. Based on hourly soundings of F2 critical frequency (foF2) and the F layer virtual height (h´F), effects over the ionosphere were also detected as consequence of volcanic eruptions. In some cases a decrease in the amplitude variation of foF2 and an increase in h´F has been noticed, respect to the behavior of these parameters during the day previous and after the eruption in the Andes mountain range. In the present work, the analysis of volcanic effects over the ionosphere based on hourly data will be extended to other regions. Although volcanic eruption effects over the ionosphere are associated to short-term variations in the time scale of minutes to a few hours, possibly, after a volcanic eruption, an overall expansion of the ionosphere, with a consequent up-shift of the F layer and decrease of the electron density takes place which could be noticed in hourly records.