Influence of the intraseasonal variability on heat waves in subtropical South America

The influence of the intraseasonal variability on heat wave development over subtropical South America during austral summer is analyzed. The role of the South Atlantic Convergence Zone (SACZ) on this development is documented. Results show that intraseasonal variability can explain on average at le...

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Autores principales: Cerne, Silvia Bibiana, Vera, Carolina Susana
Publicado: 2011
Materias:
Heat waves
Intraseasonal variability
SACZ
South America
Temperature
Warm season
air temperature
anticyclone
atmospheric circulation
atmospheric wave
regional climate
Rossby wave
seasonal variation
summer
warming
Pacific Ocean
Pacific Ocean (Central)
Pacific Ocean (Equatorial)
Pacific Ocean (South)
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v36_n11-12_p2265_Cerne
http://hdl.handle.net/20.500.12110/paper_09307575_v36_n11-12_p2265_Cerne
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09307575_v36_n11-12_p2265_Cerne
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spelling paper:paper_09307575_v36_n11-12_p2265_Cerne2025-07-30T18:28:50Z Influence of the intraseasonal variability on heat waves in subtropical South America Cerne, Silvia Bibiana Vera, Carolina Susana Heat waves Intraseasonal variability SACZ South America Temperature Warm season air temperature anticyclone atmospheric circulation atmospheric wave regional climate Rossby wave seasonal variation summer warming Pacific Ocean Pacific Ocean (Central) Pacific Ocean (Equatorial) Pacific Ocean (South) South America The influence of the intraseasonal variability on heat wave development over subtropical South America during austral summer is analyzed. The role of the South Atlantic Convergence Zone (SACZ) on this development is documented. Results show that intraseasonal variability can explain on average at least 32% of summer temperature variance. Moreover, 73% of the heat waves in subtropical South America develop in association with an active SACZ. The analysis of pentad maps shows that warm conditions in the region under study develop in association with the strengthening of an anticyclonic anomaly, which is discernible over the subtropical regions at least 15 days before temperature peak occurrence. That circulation anomaly is embedded in a large-scale Rossby wave train extending along the South Pacific Ocean that is linked to convection anomalies at the equatorial western and central Pacific Ocean. In addition, the development of the anticyclonic circulation over subtropical South America appears to be strengthened by the subsidence conditions promoted by the active SACZ, which result in temperature rise in the subtropical region under relatively dry conditions. On the other hand, during the last 2 days of evolution, SACZ activity weakens and the progressive temperature rise in the region is dominated by warmer and moister air being anomalously advected from the north. Results confirm the important role that SACZ activity on intraseasonal time scales has in inducing persistent circulation anomalies at the subtropical regions that can result in the development of persistent heat waves, and very extreme daily temperature. © 2010 Springer-Verlag. Fil:Cerne, S.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vera, C.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v36_n11-12_p2265_Cerne http://hdl.handle.net/20.500.12110/paper_09307575_v36_n11-12_p2265_Cerne
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Heat waves
Intraseasonal variability
SACZ
South America
Temperature
Warm season
air temperature
anticyclone
atmospheric circulation
atmospheric wave
regional climate
Rossby wave
seasonal variation
summer
warming
Pacific Ocean
Pacific Ocean (Central)
Pacific Ocean (Equatorial)
Pacific Ocean (South)
South America
spellingShingle Heat waves
Intraseasonal variability
SACZ
South America
Temperature
Warm season
air temperature
anticyclone
atmospheric circulation
atmospheric wave
regional climate
Rossby wave
seasonal variation
summer
warming
Pacific Ocean
Pacific Ocean (Central)
Pacific Ocean (Equatorial)
Pacific Ocean (South)
South America
Cerne, Silvia Bibiana
Vera, Carolina Susana
Influence of the intraseasonal variability on heat waves in subtropical South America
topic_facet Heat waves
Intraseasonal variability
SACZ
South America
Temperature
Warm season
air temperature
anticyclone
atmospheric circulation
atmospheric wave
regional climate
Rossby wave
seasonal variation
summer
warming
Pacific Ocean
Pacific Ocean (Central)
Pacific Ocean (Equatorial)
Pacific Ocean (South)
South America
description The influence of the intraseasonal variability on heat wave development over subtropical South America during austral summer is analyzed. The role of the South Atlantic Convergence Zone (SACZ) on this development is documented. Results show that intraseasonal variability can explain on average at least 32% of summer temperature variance. Moreover, 73% of the heat waves in subtropical South America develop in association with an active SACZ. The analysis of pentad maps shows that warm conditions in the region under study develop in association with the strengthening of an anticyclonic anomaly, which is discernible over the subtropical regions at least 15 days before temperature peak occurrence. That circulation anomaly is embedded in a large-scale Rossby wave train extending along the South Pacific Ocean that is linked to convection anomalies at the equatorial western and central Pacific Ocean. In addition, the development of the anticyclonic circulation over subtropical South America appears to be strengthened by the subsidence conditions promoted by the active SACZ, which result in temperature rise in the subtropical region under relatively dry conditions. On the other hand, during the last 2 days of evolution, SACZ activity weakens and the progressive temperature rise in the region is dominated by warmer and moister air being anomalously advected from the north. Results confirm the important role that SACZ activity on intraseasonal time scales has in inducing persistent circulation anomalies at the subtropical regions that can result in the development of persistent heat waves, and very extreme daily temperature. © 2010 Springer-Verlag.
author Cerne, Silvia Bibiana
Vera, Carolina Susana
author_facet Cerne, Silvia Bibiana
Vera, Carolina Susana
author_sort Cerne, Silvia Bibiana
title Influence of the intraseasonal variability on heat waves in subtropical South America
title_short Influence of the intraseasonal variability on heat waves in subtropical South America
title_full Influence of the intraseasonal variability on heat waves in subtropical South America
title_fullStr Influence of the intraseasonal variability on heat waves in subtropical South America
title_full_unstemmed Influence of the intraseasonal variability on heat waves in subtropical South America
title_sort influence of the intraseasonal variability on heat waves in subtropical south america
publishDate 2011
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09307575_v36_n11-12_p2265_Cerne
http://hdl.handle.net/20.500.12110/paper_09307575_v36_n11-12_p2265_Cerne
work_keys_str_mv AT cernesilviabibiana influenceoftheintraseasonalvariabilityonheatwavesinsubtropicalsouthamerica
AT veracarolinasusana influenceoftheintraseasonalvariabilityonheatwavesinsubtropicalsouthamerica
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