Teleconnections force interannual‐to‐decadal tidal variability in the Lagoon of Venice (northern Adriatic)

Abstract

[1] In the present investigation, for the first time, fundamental characteristics of autumn and winter average sequences of sea level heights (SLH) that were recorded in the Lagoon of Venice (northern Adriatic, in the Mediterranean Sea) during the period 1872-2004 are investigated. Interannual-to-decadal variability of Venetian SLH is found to reflect the variability of the most prominent Euro-Atlantic teleconnections (EATs). In particular, the North Atlantic Oscillation (NAO), the East Atlantic/Western Russian, and the Scandinavian patterns are found to contribute to generate the $5-year, $8-year and $22-year peaks that dominate the spectra of seasonal Venetian SLH. Among the possible oceanic and atmospheric phenomena downscaling interannual-to-decadal large-scale atmospheric signals into the observed variability in the Venetian SLH, we explore inverse barometer effect, wind-driven setup, and the thermohaline circulation of both the Adriatic and the Mediterranean seas. All these phenomena are assessed to display some of the typical features of the shared interannual-to-decadal variability of both Venetian SLH and EATs. Our analysis shows also that the decadal variability of winter Venetian SLH is closely linked with variations in solar activity: in particular, the winter SLH multidecadal pattern is found to be correlated, with very high statistical confidence, to the Hale Cycles pattern ($22 years), which describes the series of sunspot cycles with alternating opposite polarity. The marked signature of Hale Cycles on the leading mode of multidecadal sea level pressure winter variability (which is practically indistinguishable from the inverse wintertime NAO) is also detailed to further support the hypothesis of a Sun-Venetian SLH association.

A possible solar pacemaker for Holocene fluctuations of a salt-marsh in southern Italy

“…Ferraro and Mazzarella (1998) have shown that solar activity, exerting a direct control on atmospheric pressure, influences the water circulation in the Adriatic Sea and the related periodic algal blooms processes. A further example is the relationship between the Venetian sea level heights and variations in solar activity (Zanchettin et al, 2009). In Italy several other cases of palaeoenvironmental dynamics in marine and coastal areas have been related to sea level changes driven by variations of solar activity at different time-scales (e.g.…”

“…11-year Schwabe and 22-year Hale cycles) and correlated with climate and environmental changes (Miyahara et al, 2008;Zanchettin et al, 2008Zanchettin et al, , 2009Scafetta, 2010;Chen et al, 2011), the identification of centennialscale solar periodicities is still controversial. The scientific literature reveals that centennial periodicities of solar activity, studied both in long sequences of production rates of 14 C and 10 Be and in sunspot activity series, show an important time heterogeneity, as follows:…”

Rapid response of tidal channel networks to sea-level variations (Venice Lagoon, Italy)

“…2a): (1) 1938-1970, when higher subsidence rates were responsible for acceleration in RSLR, and (2) 1970-2010, when RSLR slowed (Rizzetto and Tosi, 2011). The identification of minor RSLR fluctuations, probably related to climatic phenomena such as the North Atlantic Oscillation (NAO), the East Atlantic/Western Russia (EA-WR), and the Scandinavian Patterns, and to variations in solar activity (Woolf et al, 2003;Kolker, 2005;Bellucci et al, 2007;Zanchettin et al, 2009), induced us to distinguish some subperiods: 1938-1950 (quite stable sea level), 1950-1970 (significant increase of RSLR), (slowing down of RSLR rates), 1990-1996 (increasing sea level), and 1996-2008 (new steady conditions). The last period (2008)(2009)(2010) was characterized by a rapid increase of RSLR, but it was too short to provide a correct trend.…”

Storm surge frequency reduction in Venice under climate change

“…The observed tides used in this study are those of the "AlteBasse" (Italian for "HighLow") dataset prepared by Battistin and Canestrelli (2006), which covers the period 1872-2004, and used in studies such as Zanchettin et al (2009). The astronomical tidal component was obtained from Dr Alberto Tomasin (CNR, Venezia).…”

“…about 50% of tides larger than 120 cm are accompanied by storm surges larger than 90 cm) found no trend in flooding events but highlighted the presence of large inter-decadal variability in extreme surge levels. The understanding of this inter-decadal variability is an important scientific and practical aspect (see also Tomasin 2002, Zanchettin et al 2009Barriopedro et al 2010) and will be considered in this work. However, the main focus of the present study is to analyse how future extreme storm surge levels may change under climate change.…”