engleski

A summertime near-ground turbulence of the Bora wind

Bora is a strong, temporally and spatially very variable wind that blows along the eastern Adriatic coast. Although Bora’s average wind velocity is not that large, as it rarely exceeds 15 to 20 m/s, it creates significant problems to traffic, infrastructure and human activities in general due to its gustiness, when the wind velocity reaches five times the average value. Previous meteorological and geophysical studies laid grounds on Bora’s large- and mesoscale- motions, but further work is still required to further analyze Bora turbulence in a form usable for engineers. In this study, the unique 3-level high-frequency measurements carried out on a meteorological tower on Pometeno brdo in the hinterland of Split, Croatia, are analyzed. For the first time turbulence intensity components in x-, y- and z- direction, as well as turbulent Reynolds shear stress, are analyzed for the summertime Bora. An interesting feature is an increase in turbulence intensity and a decrease in turbulent Reynolds shear stress with decreasing Bora wind velocity and vice versa. When the average wind velocity is larger than 5 m/s, the observed turbulence parameters remain nearly constant during this summertime Bora episode.

Bora; turbulence; field measurements

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