Local and large-scale controls of the exceptional Venice floods of November 2019

Ferrarin, Christian; Bajo, Marco; Benetazzo, Alvise; Cavaleri, Luigi; Chiggiato, Jacopo; Davison, Silvio; Davolio, Silvio; Lionello, Piero; Orlić, Mirko; Umgiesser, Georg

doi:10.1016/j.pocean.2021.102628

Cited by 48 publications

(70 citation statements)

References 47 publications

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“…In this case the storm surge was relatively modest, and the exceptional water level was caused by the superposition of PAW surges, positive astronomical tide, and an unprecedented contribution caused by a meteotsunami. After the exceptionally high water on 12 November, three successive events with water height above 140 cm occurred in just 5 d. As reported in Ferrarin et al (2021), these events were driven by three separate sirocco wind episodes in the Adriatic Sea, which did not trigger any significant seiches. These flood events were determined by the overlapping of the maximum meteorological contribution, the tide peak, and a persistently high monthly mean sea level in the northern Adriatic.…”

Section: A Description Of the Largest Past Eventssupporting

confidence: 63%

“…The contribution of meteotsunamis and PAW surges to extreme sea level events in Venice has not been thoroughly investigated to date. However, the recent 12 November 2019 event uncovered their important role in flooding in Venice (Ferrarin et al, 2021). Therefore, in general, the hazard and probability of an extreme sea level should also include these two contributions (see Sect.…”

Section: Tides Seiches and Atmospherically Forced Sea Level Anomaliesmentioning

confidence: 99%

“…The contributions of storm surge, PAW surge, meteotsunamis and mesoscale atmospheric variability (MAV), seiches, and IDAS variability have been estimated using digital bandpass filters in the time domain assuming Fourier decomposition, following Ferrarin et al (2021). The procedure is straightforward for seiches and tides, which can be isolated by applying bandpass filters around their known frequencies.…”

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

“…A 10 h cut-off period allows the synoptic-scale and MAV setup (including meteotsunamis) to be distinguished as the latter has timescales in the range of the 10 min period of a pure buoyancy oscillation to the 17 h period of mid-latitude inertial oscillations (Markowsky and Richardson, 2010). On a practical basis, Ferrarin et al (2021) have used the 10 h threshold for separating responses to a cyclone moving in an eastward direction above the Mediterranean from a lowpressure mesoscale system travelling in a north-westward direction along the western Adriatic coast in their analysis of the 12 November 2019 event. The separation between PAW surges and IDAS variability was achieved by applying a lowpass filter with the cut-off period placed at 120 d. The values of the contributions to water heights above 140 cm are shown in Table 1.…”

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

“…The meteorological and marine conditions that led to major storm surge events have been assessed with reanalyses and dedicated model simulations, including the catastrophic storm surges of 4 November 1966 (De Zolt et al, 2006;Roland et al, 2009;Cavaleri et al, 2010), 22 December 1979 (Cavaleri et al, 2010), 1 December 2008(Medugorac et al, 2016, 1 November 2012 (Medugorac et al, 2016), and 12 November 2019 (Ferrarin et al, 2021). Bertotti et al (2011) modelled five important events that occurred between 1966 and 2008.…”

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

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Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

Lionello

Barriopedro

Ferrarin

et al. 2021

Nat. Hazards Earth Syst. Sci.

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Abstract. Floods in the Venice city centre result from the superposition of several factors: astronomical tides; seiches; and atmospherically forced fluctuations, which include storm surges, meteotsunamis, and surges caused by atmospheric planetary waves. All these factors can contribute to positive water height anomalies individually and can increase the probability of extreme events when they act constructively. The largest extreme water heights are mostly caused by the storm surges produced by the sirocco winds, leading to a characteristic seasonal cycle, with the largest and most frequent events occurring from November to March. Storm surges can be produced by cyclones whose centres are located either north or south of the Alps. Historically, the most intense events have been produced by cyclogenesis in the western Mediterranean, to the west of the main cyclogenetic area of the Mediterranean region in the Gulf of Genoa. Only a small fraction of the inter-annual variability in extreme water heights is described by fluctuations in the dominant patterns of atmospheric circulation variability over the Euro-Atlantic sector. Therefore, decadal fluctuations in water height extremes remain largely unexplained. In particular, the effect of the 11-year solar cycle does not appear to be steadily present if more than 100 years of observations are considered. The historic increase in the frequency of floods since the mid-19th century is explained by relative mean sea level rise. Analogously, future regional relative mean sea level rise will be the most important driver of increasing duration and intensity of Venice floods through this century, overcompensating for the small projected decrease in marine storminess. The future increase in extreme water heights covers a wide range, largely reflecting the highly uncertain mass contributions to future mean sea level rise from the melting of Antarctica and Greenland ice sheets, especially towards the end of the century. For a high-emission scenario (RCP8.5), the magnitude of 1-in-100-year water height values at the northern Adriatic coast is projected to increase by 26–35 cm by 2050 and by 53–171 cm by 2100 with respect to the present value and is subject to continued increase thereafter. For a moderate-emission scenario (RCP4.5), these values are 12–17 cm by 2050 and 24–56 cm by 2100. Local subsidence (which is not included in these estimates) will further contribute to the future increase in extreme water heights. This analysis shows the need for adaptive long-term planning of coastal defences using flexible solutions that are appropriate across the large range of plausible future water height extremes.

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Section: A Description Of the Largest Past Eventssupporting

confidence: 63%

Section: Tides Seiches and Atmospherically Forced Sea Level Anomaliesmentioning

confidence: 99%

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

Section: A Description Of the Largest Past Eventsmentioning

confidence: 99%

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Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

Lionello

Barriopedro

Ferrarin

et al. 2021

Nat. Hazards Earth Syst. Sci.

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A high‐impact meso‐beta vortex in the Adriatic Sea

Miglietta

Buscemi

Dafis

et al. 2023

Quart J Royal Meteoro Soc

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On the evening of November 12, 2019, an exceptional high tide -the second-highest in the ranking since sea-level data have been recorded -hit the city of Venice in northern Italy and its entire lagoon, damaging a large part of its historical center. A small warm-core mesoscale cyclone, which formed in the central Adriatic Sea and intensified during its northwestward movement toward the Venice lagoon, was responsible for the event. The cyclone was preceded by intense northeasterlies (Bora) in the northern Adriatic, which turned to southeasterlies (Sirocco) and then southwesterlies after its passage. Simulations with different initialization times were carried out with the Weather Research and Forecasting (WRF) model. Simulation results show a strong sensitivity to the initial conditions, since the track (and strength) of the cyclone was determined by the exact position of an upper-level potential vorticity (PV) streamer. The factors responsible for the cyclone development and its characteristics are also investigated. The pre-existence of positive low-level cyclonic vorticity, associated with the convergence of the Sirocco and Bora winds in the central Adriatic, made the environment favorable for cyclone development. Also, the interaction between the upper-level PV anomaly and the low-level baroclinicity, created by the advection of warm, humid air associated with the Sirocco, was responsible for the cyclone's intensification, in a manner similar to a transitory (stable) baroclinic interaction at small horizontal scales. Sensitivity experiments reveal that convection, latent heat release and sea-surface fluxes did not play a significant role, indicating that this cyclone did not show tropical-like characteristics, notwithstanding its low-level warm core. Thus, the warm-core feature appears mainly as a characteristic of the environment in which the cyclone developed rather than a consequence of diabatic processes. Lastly, the cyclone does not fall into any of the existing categories for Adriatic cyclones.

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The contribution of a mesoscale cyclone and associated meteotsunami to the exceptional flood in Venice on November 12, 2019

Ferrarin

Orlić

Bajo

et al. 2023

Quart J Royal Meteoro Soc

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On November 12, 2019, an exceptional flood event took place in Venice, second only to the one that occurred on November 4, 1966. The sea level reached a peak value of 1.89 m above the local datum determining the flooding of almost 90% of the pedestrian surface of the historical city. Several processes concurred to raise the water level in Venice and the northern Adriatic Sea on November 12, 2019. Among these, a fast‐moving mesoscale cyclone travelled at about 12 m s in the northwestward direction over the northern Adriatic Sea, raising the sea levels at the shore in front of the Lagoon of Venice. High‐resolution numerical simulations indicated that atmosphere–ocean resonance occurred on November 12, 2019, generating a meteotsunami‐like wave that contributed significantly to the extreme sea level in Venice. The relative contributions of the wind and air pressure to the peak sea level were also estimated. Additional numerical experiments were performed to prove the occurrence of Proudman resonance and to determine a transfer function of such high‐frequency sea‐level perturbations for the Lagoon of Venice.

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Local and large-scale controls of the exceptional Venice floods of November 2019

Cited by 48 publications

References 47 publications

Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

A high‐impact meso‐beta vortex in the Adriatic Sea

The contribution of a mesoscale cyclone and associated meteotsunami to the exceptional flood in Venice on November 12, 2019

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