Climatological Study of Extreme Wind Events in a Coastal Area

Long-term sodar measurements (Aug 2008–Oct 2016) of wind and turbulence profiles with high spatial (10 m) and temporal (10 min) resolution were performed at the southern Bulgarian Black Sea coast. This data has provided an opportunity to define “rare” values of meteorological parameters within their statistical distributions and to identify them as extreme events according to the Intergovernmental Panel on Climate Change. The statistical analysis of wind speed profiles has been performed for the eight-year period using the two parameter Weibull distribution. The determination of the ninety-percentile of this statistical distribution (at every sodar measurement level from 30 up to 600 m) has given values (“rare” events) that have defined the theoretical extreme wind speed profile (reference profile). On this basis, the extreme profiles during the reviewed period have been determined. Analysis of the distribution of the situations with extreme weather events by months and hours for the entire period has been performed. The multiple time series with the registered extreme profiles have been used to derive averaged parameters defining the vertical structure of the coastal boundary layer during extreme events. The thermodynamic state of the coastal boundary layer according to the Pasquill-Gifford classification has been revealed.