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

Abstract

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.