Pregled bibliografske jedinice broj: 781173
On the near-ground Bora turbulence
On the near-ground Bora turbulence // 33rd International Conference on Alpine Meteorology (ICAM 2015)
Innsbruck, Austrija, 2015. (poster, međunarodna recenzija, sažetak, znanstveni)
CROSBI ID: 781173 Za ispravke kontaktirajte CROSBI podršku putem web obrasca
Naslov
On the near-ground Bora turbulence
Autori
Lepri, Petra ; Večenaj, Željko ; Kozmar, Hrvoje ; Grisogono, Branko
Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni
Skup
33rd International Conference on Alpine Meteorology (ICAM 2015)
Mjesto i datum
Innsbruck, Austrija, 31.08.2015. - 04.09.2015
Vrsta sudjelovanja
Poster
Vrsta recenzije
Međunarodna recenzija
Ključne riječi
Bora wind; Vertical wind profiles; Turbulence
Sažetak
Bora is a strong, temporally and spatially very variable downslope wind. While the average Bora wind velocity is not that significant, the Bora gusts can be very hazardous creating considerable difficulties for traffic, structures and human activities. In particular, during the gusts, the Bora wind velocity can reach velocities up to five times the average values. In order to elucidate Bora wind characteristics more closely, unique 3- level, high-frequency Bora wind measurements carried out on a meteorological tower near the city of Split, Croatia, are analyzed. Vertical profile of the Bora wind velocity for the main wind direction as well as the Bora near-ground turbulence is studied. A good agreement between the average wind velocity profile with the power- law and logarithmic-law approximations is observed. A decrease in the power-law exponent and aerodynamic surface roughness length, and an increase in friction velocity with increasing Bora wind velocity indicate a rural-like velocity profile for larger wind velocities and an urban- like velocity profile for smaller wind velocities. These results are interesting because in the engineering community it is commonly accepted that the aerodynamic characteristics at a particular site remain nearly the same during various wind regimes. The thermal stratification of the atmospheric surface layer proves to be near- neutral indicating that the Bora near-ground turbulence is predominantly generated mechanically due to an intense mixing, while the thermal effects are considered to be negligible. For mean wind velocities larger than 5 m/s, turbulence intensity and Reynolds shear stress appear to be constant, i.e. not dependent on the meandering of the mean wind velocity. An increase in turbulence length scales with increasing Bora wind velocity and vice versa is observed.
Izvorni jezik
Engleski
