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Titel |
Lightning activity, rainfall and flash flooding – occasional or interrelated events? A case study in the island of Crete |
VerfasserIn |
A. G. Koutroulis, M. G. Grillakis, I. K. Tsanis, V. Kotroni, K. Lagouvardos |
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 ; 12, no. 4 ; Nr. 12, no. 4 (2012-04-10), S.881-891 |
Datensatznummer |
250010689
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Publikation (Nr.) |
copernicus.org/nhess-12-881-2012.pdf |
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Zusammenfassung |
The majority of cyclones passing over Crete in late autumn to early winter
originate from southwest, west and northwest and are of varying size and
intensity. A number of these cyclones cause flash floods. The present study
reports the possible relationships between lighting activity and high
precipitation related to flash flood events. In this study an attempt was
made to correlate the lightning number and location, recorded by the ZEUS
lightning detection system, with the rainfall characteristics for sixteen
rain events (4 flood and 12 non-flood events) on the island of Crete, during
the period 2008–2009. Spatiotemporal analysis of rain and rain rate with
flash count was performed with respect to distance (radius) of flashes from
raingauge location at various temporal scales, in order to examine the
correlation of accumulated rainfall and lightning activity. The maximum
attained statistical significant correlation was obtained within a circular area
of an average radius of 15 km around the raingauge, and an average time lag
of flash count prior precipitation accumulation of 15 min. The maximum
correlation between the lightning and rainfall data is obtained for shorter
time lags for the flood events (15 min) than the non-flood events (25 min),
that could reflect the faster propagation of flood triggering storms due to
high convective activity. Results show increased lightning activity
occurring during flood triggering storms, by an average of four times
higher. Furthermore, there is evidence that the number of flashes that occur
during a precipitation event is related to precipitation depth when the
latter is adequate to produce a flood event. Differences between flood and
non-flood producing storms need to be further assessed by analyzing more
independent parameters, including the synoptic conditions and dominant flash
flood hydrological generating processes. |
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