Fig. 2

Comparison between the polar diagrams of wind direction and intensity of different meteorological datasets. LIBR: radio-soundings recorded at Brindisi station (≈300 km from Vesuvius) between 1 July 1996 and 31 December 2012 (12,788 records); LIRE: radio-soundings recorded at Pratica di Mare (Rome, ≈200 km form Vesuvius) station between 1 November 1995 and 21 December 2013 (14,976 records); NOOA1: data from the NCEP/NCAR Reanalysis 1 (Kalnay et al. 1996), between 1991–2010 at 15E,40N (≈100 km from Vesuvius, daily averages, 7,305 records); NOAA2: data from NOAA/CIRES 20th Century Reanalysis 2 (Compo et al. 2006, 2011) between 1991–2010 at 14E, 40N (≈100 km from Vesuvius, 6 h averages, 29,220 records); ERAI: data from the ECMWF Era Interim dataset (Berrisford et al. 2011) between 1991–2010 at 14.25E,40.5N (≈40 km from Vesuvius, 6 h averages, 29,220 records). Please note that, differently from the convention usually adopted in meteorology, these plots do not represent the direction of provenance of the wind, but the direction towards which the wind blows