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Titel |
Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy) |
VerfasserIn |
P. Vita, V. Allocca, F. Manna, S. Fabbrocino |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 5 ; Nr. 16, no. 5 (2012-05-11), S.1389-1399 |
Datensatznummer |
250013295
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Publikation (Nr.) |
copernicus.org/hess-16-1389-2012.pdf |
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Zusammenfassung |
Thus far, studies on climate change have focused mainly on the variability
of the atmospheric and surface components of the hydrologic cycle,
investigating the impact of this variability on the environment, especially
with respect to the risks of desertification, droughts and floods.
Conversely, the impacts of climate change on the recharge of aquifers and on
the variability of groundwater flow have been less investigated, especially
in Mediterranean karst areas whose water supply systems depend heavily upon
groundwater exploitation.
In this paper, long-term climatic variability and its influence on
groundwater recharge were analysed by examining decadal patterns of
precipitation, air temperature and spring discharges in the Campania region
(southern Italy), coupled with the North Atlantic Oscillation (NAO).
The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature
stations with the most continuous functioning. The time series of the winter
NAO index and of the discharges of 3 karst springs, selected from those
feeding the major aqueducts systems, were collected for the same period.
Regional normalised indexes of the precipitation, air temperature and karst
spring discharges were calculated, and different methods were applied to
analyse the related time series, including long-term trend analysis using
smoothing numerical techniques, cross-correlation and Fourier analysis.
The investigation of the normalised indexes highlighted the existence of
long-term complex periodicities, from 2 to more than 30 yr, with
differences in average values of up to approximately ±30% for
precipitation and karst spring discharges, which were both strongly
correlated with the winter NAO index.
Although the effects of the North Atlantic Oscillation (NAO) had already
been demonstrated in the long-term precipitation and streamflow patterns of
different European countries and Mediterranean areas, the results of this
study allow for the establishment of a link between a large-scale
atmospheric cycle and the groundwater recharge of carbonate karst aquifers.
Consequently, the winter NAO index could also be considered as a proxy to
forecast the decadal variability of groundwater flow in Mediterranean karst
areas. |
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