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| Titel |
Rainfall variability related to sea surface temperature anomalies in a Pacific–Andean basin into Ecuador and Peru |
| VerfasserIn |
L. Pineda, V. Ntegeka, P. Willems |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: ENSO South America ; Nr. 33 (2013-04-02), S.53-62 |
| Datensatznummer |
250019081
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| Publikation (Nr.) |
 copernicus.org/adgeo-33-53-2013.pdf |
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| Zusammenfassung |
The spatiotemporal modes of seasonal rainfall variability and their relation
with sea surface temperature anomalies (SSTA 1.2 indices) are examined in
the transition from the coastal plain towards the western Andes cordillera
in southern Ecuador/northwestern Peru using instrumental records (1970–2000)
collected from the Catamayo–Chira basin. A multi-criteria data analysis is
conducted within different elevation ranges. The criteria involve rotated
principal components, cross correlations and temporal changes of anomalies
in rainfall quantiles.
The results confirm that SSTA 1.2 indices influence rainfall variability
over the coastal plain (< 510 m a.s.l.) where forcing is dominant within
December–May. The El Niño Southern Oscillation also plays a role inland
of the coastal plain where a region of ENSO-like rainfall variability is
found on the southeastern part of the basin (4°30'–5° S/79°15'–80° W)
within March–May (MAM). This suggests
that inland distance and elevation are only partial controls of
ocean–atmospheric forcing up to ~ 1300 m a.s.l. Our analysis also
provides evidence of the SSTA 1.2 indices influence in a large altitudinal
range ~ 1400–2700 m a.s.l. confined to the southeastern basin.
This region is found consistently perturbed by ENSO within MAM. We conclude
that geo-morphological features of the southwestern Ecuadorian Andean ridges
play a twofold role in the control of ocean–atmospheric forcing. They can
modulate the atmospheric circulation, leading to a dissipation of the signal,
or they might favor meteorological processes, leading to enhancement of
orographic precipitation. This would explain the observed ENSO signals in
instrumental records at locations as high as 2700 m a.s.l. |
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