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Decoupling of ground level pressures observed in Italian volcanoes: are they driven by space weather geo-effectiveness?
- Publication date
- Publisher
- INGV
Abstract
Investigations on correlation drops between near-ground atmospheric
pressures measured at sea level and at higher altitudes on Italian volcanoes
have been carried out. We looked for perturbations of the atmospheric
pressure field driven by volcanic activity, but not excluding possible
external triggers for the observed anomalies. Decorrelations between atmospheric
pressures measured at Stromboli Island in stations located at
different altitudes (years 2002-10) have been analysed and compared with
data from other volcanic (Vesuvius) and non volcanic (Mt. Soro) orographic
structures. We investigated as their possible triggers volcanic, meteorological
and space weather parameters, with particular attention to
Total Solar Irradiance (TSI), Kp index and Forbush decreases. Pressure
decorrelations seems to be driven by astronomic cycles, with maxima in
summer and minima in winter. A further contribution was found, seemingly
assignable to TSI anomalies, with correlation minima occurring 12
hours after these but only during phases of high Sun activity. Moreover,
during the same phases a main periodicity of about 27 days in pressure
decorrelations was revealed by FFT analysis. This period is the same of
the Sun Carrington rotation, expressing the periodic reappearance of
sunspot groups on Sun’s surface. The strong similarity between recurrences
of sunspot number and atmospheric pressure anomalies further
supports the role of the former as a possible trigger for the latter