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Titel |
The mobility of Atlantic baric depressions leading to intense precipitation over Italy: a preliminary statistical analysis |
VerfasserIn |
N. Tartaglione, A. Speranza, F. Dalan, T. Nanni, M. Brunetti, M. Maugeri |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 6, no. 3 ; Nr. 6, no. 3 (2006-06-06), S.451-458 |
Datensatznummer |
250003508
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Publikation (Nr.) |
copernicus.org/nhess-6-451-2006.pdf |
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Zusammenfassung |
The speed of Atlantic surface depressions, occurred during the autumn and winter seasons and that lead to intense
precipitation over Italy from 1951 to 2000, was investigated. Italy was divided into 5 regions as documented in previous
climatological studies (based on Principal Component Analysis). Intense precipitation events were selected on the basis
of in situ rain gauge data and clustered according to the region that they hit. For each intense precipitation event we tried to
identify an associated surface depression and we tracked it, within a large domain covering the Mediterranean and Atlantic
regions, from its formation to cyclolysis in order to estimate its speed. "Depression speeds" were estimated with 6-h
resolution and clustered into slow and non-slow classes by means of a threshold, coinciding with the first quartile of
speed distribution and depression centre speeds were associated with their positions.
Slow speeds occurring over an area including Italy and the western Mediterranean basin showed frequencies higher than 25%,
for all the Italian regions but one.
The probability of obtaining by chance the observed more than 25% success rate was estimated
by means of a binomial distribution. The statistical reliability of the result is confirmed for only one region.
For Italy as a whole, results were confirmed at 95% confidence level. Stability of the statistical inference,
with respect to errors in estimating depression speed and changes in the threshold of slow depressions, was analysed
and essentially confirmed the previous results. |
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