Abstract
The North Adriatic Dense Water (NAddW) – the densest Mediterranean
water generated by extreme cooling during wintertime hurricane-strength
winds – drives the thermohaline circulation, ventilates the deep
layers, and changes the biogeochemical properties of the Adriatic Sea.
However, modelling the dynamical properties of such dense water at the
climate scale has been a challenge for decades due to the complex
coastal geomorphology of the Adriatic basin not properly reproduced by
existing climate models. To overcome these deficiencies, a 31-year-long
simulation (1987-2017) of the Adriatic Sea and Coast (AdriSC)
kilometre-scale atmosphere-ocean model is used to analyse the main NAddW
dynamical phases (i.e., generation, spreading and accumulation). The
study highlights four key results. First, during winter, the NAddW
densities are higher in the shallow northern Adriatic shelf than in the
deeper Kvarner Bay – where 25-35% of the overall NAddW are found to be
generated – due to a median bottom temperature difference of 2°C
between the two generation sites. Second, the NAddW mass transported
across most of the Adriatic peaks between February and May, except along
the western side of the Otranto Strait. Third, for the accumulation
sites, the bottom layer of the Kvarner Bay is found to be renewed
annually while the renewal occurs every 1–3 years in the Jabuka Pit and
every 5–10 years in the deep Southern Adriatic Pit. Fourth, the NAddW
cascading and accumulation is more pronounced during basin-wide
high-salinity conditions driven by circulation changes in the northern
Ionian Sea.