Seasonal precipitation variability modes over South America associated to El Niño-Southern Oscillation (ENSO) and non-ENSO components during the 1951–2016 period
(2021) In International Journal of Climatology 41(8). p.4321-4338- Abstract
Anomalous seasonal patterns of precipitation variability over South America (SA) associated with El Niño-Southern Oscillation (ENSO) and non-ENSO (residual) conditions were assessed during 1951–2016. Patterns were obtained from empirical orthogonal functions analysis of total and residual precipitation seasonal anomalies. In austral spring and summer, precipitation variability is dominated by a dipolar anomaly mode with a centre extending from northwestern to northeastern SA and another in central-eastern Brazil and part of southeastern SA (SESA) during spring, and a centre in northwestern SA and another extending from northeastern SA to central and eastern Brazil and central SESA, during summer. These modes are associated with ENSO to... (More)
Anomalous seasonal patterns of precipitation variability over South America (SA) associated with El Niño-Southern Oscillation (ENSO) and non-ENSO (residual) conditions were assessed during 1951–2016. Patterns were obtained from empirical orthogonal functions analysis of total and residual precipitation seasonal anomalies. In austral spring and summer, precipitation variability is dominated by a dipolar anomaly mode with a centre extending from northwestern to northeastern SA and another in central-eastern Brazil and part of southeastern SA (SESA) during spring, and a centre in northwestern SA and another extending from northeastern SA to central and eastern Brazil and central SESA, during summer. These modes are associated with ENSO to a greater extent during spring than summer. In summer, there is a strong association of the dipolar precipitation pattern with sea surface temperature (SST) anomalies on the east coast of Brazil, which indicates local influence. In austral fall, SST anomalies in the tropical South Atlantic relate to precipitation anomalies in northeast SA, and those in the tropical north Atlantic (TNA) to precipitation anomalies in northwestern SA, through the intertropical convergence zone anomalous position modulated by SST anomalies. In this same condition, the ENSO acts only to intensify or weaken the dominant precipitation pattern, depending on its phase, mainly over SESA. In contrast, the second variability mode in fall is characterized by positive SST anomalies in the Indian Ocean and equatorial and southern Atlantic Ocean and negative in the TNA. The importance of ENSO and the Indian Ocean in the characterization of the SST dipole in the tropical Atlantic explains the main changes in precipitation patterns over northeastern Brazil not been discussed in previous studies.
(Less)
- author
- de Souza, Itamara Parente ; Andreoli, Rita Valéria ; Kayano, Mary Toshie ; Vargas, Franci Flores ; Cerón, Wilmar L. ; Martins, Jorge Alberto LU ; Freitas, Edmilson and de Souza, Rodrigo Augusto Ferreira
- organization
- publishing date
- 2021-06-30
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- ENSO, Indian Ocean, precipitation, South America, SST, Tropical Atlantic
- in
- International Journal of Climatology
- volume
- 41
- issue
- 8
- pages
- 18 pages
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- scopus:85102391932
- ISSN
- 0899-8418
- DOI
- 10.1002/joc.7075
- language
- English
- LU publication?
- yes
- id
- 07e03946-e310-4c19-813b-3afbe684135b
- date added to LUP
- 2021-03-29 14:19:40
- date last changed
- 2024-03-23 02:12:39
@article{07e03946-e310-4c19-813b-3afbe684135b,
abstract = {{<p>Anomalous seasonal patterns of precipitation variability over South America (SA) associated with El Niño-Southern Oscillation (ENSO) and non-ENSO (residual) conditions were assessed during 1951–2016. Patterns were obtained from empirical orthogonal functions analysis of total and residual precipitation seasonal anomalies. In austral spring and summer, precipitation variability is dominated by a dipolar anomaly mode with a centre extending from northwestern to northeastern SA and another in central-eastern Brazil and part of southeastern SA (SESA) during spring, and a centre in northwestern SA and another extending from northeastern SA to central and eastern Brazil and central SESA, during summer. These modes are associated with ENSO to a greater extent during spring than summer. In summer, there is a strong association of the dipolar precipitation pattern with sea surface temperature (SST) anomalies on the east coast of Brazil, which indicates local influence. In austral fall, SST anomalies in the tropical South Atlantic relate to precipitation anomalies in northeast SA, and those in the tropical north Atlantic (TNA) to precipitation anomalies in northwestern SA, through the intertropical convergence zone anomalous position modulated by SST anomalies. In this same condition, the ENSO acts only to intensify or weaken the dominant precipitation pattern, depending on its phase, mainly over SESA. In contrast, the second variability mode in fall is characterized by positive SST anomalies in the Indian Ocean and equatorial and southern Atlantic Ocean and negative in the TNA. The importance of ENSO and the Indian Ocean in the characterization of the SST dipole in the tropical Atlantic explains the main changes in precipitation patterns over northeastern Brazil not been discussed in previous studies.</p>}},
author = {{de Souza, Itamara Parente and Andreoli, Rita Valéria and Kayano, Mary Toshie and Vargas, Franci Flores and Cerón, Wilmar L. and Martins, Jorge Alberto and Freitas, Edmilson and de Souza, Rodrigo Augusto Ferreira}},
issn = {{0899-8418}},
keywords = {{ENSO; Indian Ocean; precipitation; South America; SST; Tropical Atlantic}},
language = {{eng}},
month = {{06}},
number = {{8}},
pages = {{4321--4338}},
publisher = {{John Wiley & Sons Inc.}},
series = {{International Journal of Climatology}},
title = {{Seasonal precipitation variability modes over South America associated to El Niño-Southern Oscillation (ENSO) and non-ENSO components during the 1951–2016 period}},
url = {{http://dx.doi.org/10.1002/joc.7075}},
doi = {{10.1002/joc.7075}},
volume = {{41}},
year = {{2021}},
}