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Fig. 8 | Journal of Applied Volcanology

Fig. 8

From: Probabilistic Volcanic Ash Hazard Analysis (PVAHA) I: development of the VAPAH tool for emulating multi-scale volcanic ash fall analysis

Fig. 8

Monthly mean wind direction (deg) and wind speed (m/s) for the 250mb pressure level (Tropopause) aggregated for a 64 year period (1950–2014) for four of the 16 NCEP grid points used for the Indonesian sub-region. Wind rose diagrams depict the frequency of winds blowing ‘from’ a particular direction over the 64-year period. The length of each spoke is related to the frequency that the wind blows from a particular direction (e.g. N, S E or W) over the 64-year period and each concentric circle represents a different frequency (e.g. 10 %, 20 %, 30 %) emanating from zero at the centre

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