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| Titel |
Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK |
| VerfasserIn |
P. Dissanayake, J. Brown, H. Karunarathna |
| 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 Sciences ; 15, no. 7 ; Nr. 15, no. 7 (2015-07-09), S.1533-1543 |
| Datensatznummer |
250119597
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| Publikation (Nr.) |
 copernicus.org/nhess-15-1533-2015.pdf |
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| Zusammenfassung |
| Impacts of storm chronology within a storm cluster on beach/dune erosion are
investigated by applying the state-of-the-art numerical model XBeach
to the Sefton coast, northwest England. Six temporal storm clusters of
different storm chronologies were formulated using three storms observed
during the 2013/2014 winter. The storm power values of these three events
nearly halve from the first to second event and from the second to third
event. Cross-shore profile evolution was simulated in response to the tide,
surge and wave forcing during these storms. The model was first calibrated
against the available post-storm survey profiles. Cumulative impacts of
beach/dune erosion during each storm cluster were simulated by using the
post-storm profile of an event as the pre-storm profile for each subsequent
event. For the largest event the water levels caused noticeable retreat of
the dune toe due to the high water elevation. For the other events the
greatest evolution occurs over the bar formations (erosion) and within the
corresponding troughs (deposition) of the upper-beach profile. The sequence
of events impacting the size of this ridge–runnel feature is important as it
consequently changes the resilience of the system to the most extreme event
that causes dune retreat. The highest erosion during each single storm event
was always observed when that storm initialised the storm cluster. The most
severe storm always resulted in the most erosion during each cluster, no
matter when it occurred within the chronology, although the erosion volume
due to this storm was reduced when it was not the primary event. The greatest
cumulative cluster erosion occurred with increasing storm severity; however,
the variability in cumulative cluster impact over a beach/dune cross section
due to storm chronology is minimal. Initial storm impact can act to enhance
or reduce the system resilience to subsequent impact, but overall the
cumulative impact is controlled by the magnitude and number of the storms.
This model application provides inter-survey information about morphological
response to repeated storm impact. This will inform local managers of the
potential beach response and dune vulnerability to variable storm
configurations. |
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