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| Titel |
Linking ENSO and heavy rainfall events over coastal British Columbia through a weather pattern classification |
| VerfasserIn |
P. Brigode, Z. Micovic, P. Bernardara, E. Paquet, F. Garavaglia, J. Gailhard, P. Ribstein |
| 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 ; 17, no. 4 ; Nr. 17, no. 4 (2013-04-17), S.1455-1473 |
| Datensatznummer |
250018850
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| Publikation (Nr.) |
 copernicus.org/hess-17-1455-2013.pdf |
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| Zusammenfassung |
| Classifications of atmospheric weather patterns (WPs) are widely used for the
description of the climate of a given region and are employed for many
applications, such as weather forecasting, downscaling of global circulation
model outputs and reconstruction of past climates. WP classifications were
recently used to improve the statistical characterisation of heavy rainfall.
In this context, bottom-up approaches, combining spatial distribution of
heavy rainfall observations and geopotential height fields have been used to
define WP classifications relevant for heavy rainfall statistical analysis.
The definition of WPs at the synoptic scale creates an interesting variable
which could be used as a link between the global scale of climate signals and
the local scale of precipitation station measurements. We introduce here a
new WP classification centred on the British Columbia (BC) coastal region (Canada)
and based on a bottom-up approach. Five contrasted WPs composed this
classification, four rainy WPs and one non-rainy WP, the anticyclonic
pattern. The four rainy WPs are mainly observed in the winter months (October
to March), which is the period of heavy precipitation events in coastal BC
and is thus consistent with the local climatology. The combination of this WP
classification with the seasonal description of rainfall is shown to be
useful for splitting observed precipitation series into more homogeneous
sub-samples (i.e. sub-samples constituted by days having similar atmospheric
circulation patterns) and thus identifying, for each station, the synoptic
situations that generate the highest hazard in terms of heavy rainfall
events. El Niño-Southern Oscillations (ENSO) significantly influence the
frequency of occurrence of two coastal BC WPs. Within each WP, ENSO seem to
influence only the frequency of rainy events and not the magnitudes of heavy
rainfall events. Consequently, heavy rainfall estimations do not show
significant evolution of heavy rainfall behaviour between Niño and
Niña winters. However, the WP approach captures the variability of the
probability of occurrences of synoptic situations generating heavy rainfall
depending on ENSO and opening interesting perspectives for the analysis of
heavy rainfall distribution in a non-stationary context. |
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