Naslov
Characteristics of bora pulsations in the lee of the Dinaric Alps

Autori
Petar Golem, Željko Večenaj, Hrvoje Kozmar, Branko Grisogono

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
36th International Conference on Alpine Meteorology

Mjesto i datum
Online ; St. Gallen, Švicarska, 19.06.2023. - 27.06.2023

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Downslope windstorm, pulsations, rotational spectra, bora, severe weather, mesoscale

Sažetak
Bora is a well-known downslope windstorm that blows at the NE Adriatic coast from inland towards the sea, mainly from the NE direction. One of the striking bora characteristics are the quasi-periodic gust pulsations. In this work, their characteristics during severe bora in the lee of the Dinaric Alps, near the town of Senj, are explored using rotational spectral analysis and nine months of continuous high-frequency sonic anemometer measurements. Analysis shows that the pulsations' propagation direction does not correspond to the measured near-ground wind direction. Additionally, these two directions seem to be negatively correlated, and their relative angle is larger when bora is forced by an anticyclonic pressure gradient, as opposed to when it is forced by a cyclonic one. Although the pulsations are mostly rectilinear (majority of the energy contained parallel to their propagation direction), positive rotational component is larger than the negative in all but one bora episode, and the motions can become briefly elliptical. Several more notable bora episodes exhibiting most of the aforementioned features are highlighted. Possible reasons for these observations are discussed, such as large directional shear near the top of the lee-side jet (shooting flow) and the presence of the potential vorticity banners. High-resolution simulations are planned to elucidate these observations.

Izvorni jezik
Engleski

Znanstvena područja
Geofizika

POVEZANOST RADA