Fig. 2
From: Rapid emergency assessment of ash and gas hazard for future eruptions at Santorini Volcano, Greece

Wind rose diagrams that show wind speeds and directions as a function of altitude (approximately surface, 3 km and 9.5Â km), based on statistical analyses of daily regional winds provided by the ECMWF ERA-Interim (upper) and NCEP/NCAR (lower) re-analysis data over extended periods. Note that wind rose diagrams follow standard meteorological definition and show the direction the wind is blowing from rather than to