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Titel |
Investigating annual and monthly trends in precipitation structure: an overview across Portugal |
VerfasserIn |
M. I. P. Lima, S. C. P. Carvalho, J. L. M. P. Lima |
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 ; 10, no. 11 ; Nr. 10, no. 11 (2010-11-30), S.2429-2440 |
Datensatznummer |
250008510
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Publikation (Nr.) |
copernicus.org/nhess-10-2429-2010.pdf |
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Zusammenfassung |
This work investigates recent changes in precipitation patterns manifested in
long annual and monthly precipitation time series recorded in Portugal. The
dataset comprises records from 14 meteorological stations scattered over
mainland Portugal and the Portuguese North Atlantic Islands of Madeira and
Azores; some of the time series date back to the 19th century. The data were
tested for trends using the Mann-Kendall non-parametric test and Sen's
non-parametric method, searching both for full monotonic trends over the
record period and for partial trends. Results provide no evidence for
rejecting the null hypothesis of no trend in annual precipitation, when a
monotonic linear model was used. Nevertheless, the analyses of 50 years'
moving averages showed an increase over time, in the recent past, for many of
the series in mainland Portugal and the Islands. For the longest time series
this behaviour was preceded by a decrease over time. The analyses of partial
trends in the time series suggested a sequence of alternately decreasing and
increasing trends in annual and monthly precipitation, which are sometimes
statistically significant. The trend changing points were identified. |
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