February 2003 marine atmospheric conditions and the bora over the northern Adriatic

Abstract

A winter oceanographic field experiment provided an opportunity to examine the atmospheric marine conditions over the northern Adriatic. Mean February winds are from a northeasterly direction over most of the Adriatic and a more northerly direction along the western coast. Wind speeds are fastest in jets over the NE coast during bora events and weakest in the mid‐northwestern Adriatic. Diurnal air temperature cycles are smallest on the NE coast and largest in the midwestern Adriatic. The maximum sea‐air difference is +10°C on the eastern coast and near zero on the midwestern Adriatic. Boras are northeasterly (from) wind events that sweep off Croatia and Slovenia, bringing slightly colder and drier air over the northern Adriatic. The main bora season is December to March. Winter 2002–2003 was normal for bora events. Synoptic‐scale temporal variations are correlated over the northern Adriatic. Fastest Bora winds and highest wind stress over the northern Adriatic is concentrated in four topographically controlled jets. The strongest is the Senj Jet, while the Trieste Jet extends across the entire northern Adriatic. Between each two jets is a weak wind zone. The greatest mean net heat loss is in bora jets in the NE Adriatic, where it was −438 W m−2 and is weakest in the midwestern northern Adriatic, where it was near zero. Wind stress is concentrated over the NE half of Adriatic in four bora jets, while wind stress is weak in the NW Adriatic. There is significant variation in wind stress mean and standard deviation structure over the northern Adriatic with each bora event.

The role of water mass dynamics in controlling bacterial abundance and production in the middle Adriatic Sea

“…Mediterranean water mass (density excess up to 30 kg m -3 , Vilibi , 2003), generated during 61 strong and long-lasting wintertime bora outbreaks (Dorman et al, 2007). During spring and 62 summer it moves downslope along the western Adriatic shelf, strongly hits and fills up deep 63 layers of the Jabuka Pit .…”

On the onset of bora and the formation of rotors and jumps near a mountain gap

“…Smith, 1987;Klemp and Durran, 1987;Grubišić, 1989;Jurčec and Glasnović, 1991;Bajić, 1991). Recent investigations conducted since the Mesoscale Alpine Programme (MAP) have focused more specifically on three-dimensional and small-scale aspects of bora winds: the role of mountain gaps in the formation of shear lines and potential-vorticity banners (Grubišić, 2004); the influence of gravity-wave breaking on the formation of surface wakes and jets (Jiang and Doyle, 2005); the role of boundary-layer separation in the development of gap winds (Gohm and Mayr, 2005); the dynamics and predictability of bora turbulence and gusts (Belušić and Klaić, 2004;Belušić and Klaić, 2006); the sensitivity of bora winds to the sea-surface temperature (Cesini et al, 2004;Kraljević and Grisogono, 2006); and the impact of the bora flow on ocean currents and air-sea interactions Pullen et al, 2006;Pullen et al, 2007;Dorman et al, 2006;Kuzmić et al, 2006).…”

Towards validating a last generation, integrated wave-current-sediment numerical model in coastal regions using video measurements

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