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A discussion of the links between solar variability and high-storm-surge events in Venice

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Barriopedro Cepero, David and García Herrera, Ricardo and Lionello, Piero and Pino, Cosimo (2010) A discussion of the links between solar variability and high-storm-surge events in Venice. Journal of geophysical research-atmospheres, 115 . ISSN 0148-0227

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Official URL: http://dx.doi.org/10.1029/2009JD013114




Abstract

This study explores the long-term frequency variability of high-surge events (HSEs) in the North Adriatic, the so-called acqua alta, which, particularly during autumn, cause flooding of the historical city center of Venice. The period 1948-2008, when hourly observations of sea level are available, is considered. The frequency of HSEs is correlated with the 11 year solar cycle, solar maxima being associated with a significant increase in the October-November-December HSE frequency. The seasonal geopotential height pattern at 1000 hPa (storm surge pattern; SSP) associated with the increased frequency of HSEs is identified for the whole time period and found to be similar to the positive phase of the main variability mode of the regional atmospheric circulation (empirical orthogonal function 1; EOF1). However, further analysis indicates that solar activity modulates the spatial patterns of the atmospheric circulation (EOF) and the favorable conditions for HSE occurrence (SSP). Under solar maxima, the occurrence of HSEs is enhanced by the main mode of regional atmospheric variability, namely, a large-scale wave train pattern that is symptomatic of storm track paths over northern Europe. Solar minima reveal a substantially different and less robust SSP, consisting of a meridionally oriented dipole with a preferred southward path of storm track activity, which is not associated with any dominant mode of atmospheric variability during low-solar periods. It is concluded that solar activity plays an indirect role in the frequency of HSEs by modulating the spatial patterns of the main modes of atmospheric regional variability, the favorable patterns for HSE occurrence, and their mutual relationships, so that constructive interaction between them is enhanced during solar maxima and inhibited in solar minima.


Item Type:Article
Additional Information:

© 2010 by the American Geophysical Union. NCEP reanalysis data were provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, at their Web site (http://www.cdc.noaa.gov/). The Ufficio Idrografico of Venice provided sea level data. Solar data were obtained from the National Geophysical Data Center of the NOAA at their Web site (www.ngdc.noaa.gov/stp/SOLAR/ftpsolarradio.html). This study was partially supported by EU Sixth Framework Program (CIRCE) contract 036961 (GOCE) and the ENAC project (PTDC/AAC-CLI/103567/2008) funded by the IDL-FFCUL. We also acknowledge the contribution from the ESF MedCLIVAR program.

Uncontrolled Keywords:North-Atlantic, Sea Surges, Cycle, Oscillations, Climatology, Troposphere, Patterns, Future, Area
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
Sciences > Physics > Atmospheric physics
ID Code:24413
Deposited On:30 Jan 2014 08:37
Last Modified:10 Dec 2018 15:05

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