Atmospheric origin of the devastating coupled air-sea event in the east Adriatic

Enhanced sea level oscillations with devastating effects occurred on 26/27 June 2003 in the east Adriatic. The phenomenon was recognized as a resonantly coupled air-sea interaction, where the sea wave is forced by the propagating atmospheric pressure disturbance. This study examines the dynamics and predictability of the atmospheric component of the coupled system. First, the initiation, amplification and maintenance of the system are examined. The source of the perturbation is traced back to the Alpine region, where the potentially unstable air in the westerly current lifts over the Alps resulting in convection and wave development. The wave and convective activity apparently couple in a wave-CISK manner and propagate southeastward down the eastern Adriatic coast. Due to the potentially unstable air above the Adriatic, the system additionally amplifies along its track. The dissipation of the system occurs after the landfall. Second, the performance of the numerical model at the resolution that is similar to operational NWP model resolution is examined. This severe event is highly susceptible to the details of the model configuration, presumably due to the sensitivity in coupling of the wave and MCS. Thus although the model is able to reproduce and forecast this kind of event at a fairly coarse resolution, the details of the spatial structure, as well as the time of onset, are questionable. In this case, the greatest sensitivity is primarily in the treatment of moist and convective processes.