Wind storms (extremely strong winds) in nature are associated with hazardous meteorological conditions which could cause property damages and human life loss. Therefore through the study of extremely strong winds is of vital importance both from an economic and human point of view.

The main goal of the project is to use modern remote sensing technology for measurements of profiles of wind and turbulence (MFAS SCINTEC sodar) for identifying extreme events (wind speed profiles exceeding a specific threshold) and for obtaining averaged characteristics of the structure of a coastal ABL during extreme conditions in the area of the town of Ahtopol, using time series of data with high spatial and temporal resolution in order to achieve new knowledge for vertical structure of the coastal ABL. For specific meteorological situations (periods) with high availability of extreme profiles, the mesometeorological Weather Research and Forecasting (WRF) model will be validated against observations through correlations between five pairs of measured and modelled wind field variables (wind speed, wind direction, and wind vector components). As a measure of linear correlation between two random variables Pearson correlation coefficient will be used.

Specific goals:

  • Development of a database of all measured by the sodar characteristics (wind and turbulence profiles) in the region of the town of Ahtopol for an eight-year period (August 2008 – October 2016), required for determining extreme values in the wind field.
  • Determination of a theoretical extreme wind speed profile (“sample” profile of extreme values at every level of measurement by the sodar up to 600 m with 10 m vertical resolution) on the basis of which extreme profiles and their time series will be determined and other measured by sodar parameters will be extracted.
  • Analysis of the distribution of the situations with extreme weather events by months and hours for the entire period and selecting of appropriate periods with extreme winds to focus further research on evaluation of the numerical model performance.
  • Configuring and initializing of WRF for the selected periods with extreme winds.
  • Interpolation of model output to the levels of sodar measurements.
  • Correlation analysis of measured by sodar and modeled pairs variables. Analysis of time variability and variation in height of calculated correlation coefficients.
  • Deriving of averaged characteristics of wind field and turbulence under extreme wind conditions, as well as and their dispersions using sodar data for the entire studied period.

Expected results:

  • for the first time, a detailed statistical analysis of wind speed profiles at the Bulgarian Black sea will be performed for almost eight years. The data are with high vertical and temporal resolution (10 m and 10 min, respectively) and include the atmospheric layer up to 500-600 m;
  • new knowledge will be acquired for extreme values of wind in height with high spatial resolution in the studied complex region;
  • specific situations with extreme strong winds will be identified and their monthly and diurnal distribution during every year of the remote acoustic sounding of the atmosphere at EP Ahtopol;
  • averaged characteristics and their dispersions will be obtained, describing the vertical structure of the coastal ABL for registered extreme wind profiles;
  • the mesometeorological model WRF will be evaluated for selected cases with registered extreme winds at the Bulgarian Black sea;

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