Severe marine storms in the Northern Adriatic: Characteristics and trends

This paper discusses present characteristics and trends of severe marine storminess in the Northern Adriatic. It merges oceanographic and meteorological aspects by considering storm surges, wind waves and the atmospheric cyclones that cause them. The paper introduces these three processes and the different role of south-easterly (Sirocco) and easterly (Bora) wind regimes. The specific characteristics of cyclones producing severe marine storms in terms of location where cyclogenesis occurs, trajectories and intensity, are compared with those of generic cyclones crossing northern Italy. It is shown that cyclones producing high waves and surges in most cases have different characteristics and their lists overlap only partially. However, both high wave and surge events have a similar annual cycle, with maximum activity in November and hardly any event in summer (June-July-August). The trends of severe high wave and surge events are discussed (various thresholds are considered) and they are shown to be broadly consistent. Timeseries, which show large inter-annual variability and very little overall tendencies on multi-decadal time scale, suggest progressively milder storms during the second half of the 20th century.