Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone

Autores
Liebmann, Brant; Kiladis, George; Vera, Carolina Susana; Saulo, Andrea Celeste; Carvalho, Leila
Año de publicación
2004
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Regional and large-scale circulation anomalies associated with variations in rainfall downstream of the South American low-level jet are identified and compared to those in the South Atlantic convergence zone (SACZ). Composites of precipitation associated with strong jets reveal an approximate doubling of the quantities one would expect from climatology, with an evolution of the rainfall pattern from south to north. The occurrence of extreme precipitation events follows a similar pattern. Meridional cross sections of composite wind reveal a distinct low-level jet near 208S and a baroclinic development farther south that appears to force the jet. Geopotential height, temperature, and large-scale wind composites suggest that this developing disturbance is tied to a wave train that originates in the midlatitude Pacific and turns equatorward as it crosses the Andes Mountains. Similar composites based on SACZ rainfall reveal similar features, but of opposite sign, suggesting that the phase of the wave as it crosses the Andes Mountains determines whether rainfall will be enhanced downstream of the jet or in the SACZ. The alternate suppression or enhancement of rainfall in these adjacent regions results in a precipitation ‘‘dipole.’’ Many previous studies have found a similar out-of-phase relationship over many time scales. The phase of the Madden–Julian oscillation (MJO) is composited relative to anomalous precipitation events, revealing statistically relevant amplitudes associated with rainfall both downstream of the jet and in the SACZ. The MJO is a particularly interesting intraseasonal oscillation because it has some predictability. It is speculated that the slowly varying dipole that has been observed is a consequence of the preferred phasing of synoptic waves due to variations of the planetary-scale basic-state flow, which is at times associated with the MJO.
Fil: Liebmann, Brant. National Ocean And Atmospheric Administration; Estados Unidos
Fil: Kiladis, George. National Ocean And Atmospheric Administration; Estados Unidos
Fil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina
Fil: Saulo, Andrea Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina
Fil: Carvalho, Leila. Universidade de Sao Paulo; Brasil
Materia
SOUTH AMERICA
ANDES
RAINFALL
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/182457
Acceder
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repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence ZoneLiebmann, BrantKiladis, GeorgeVera, Carolina SusanaSaulo, Andrea CelesteCarvalho, LeilaSOUTH AMERICAANDESRAINFALLhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Regional and large-scale circulation anomalies associated with variations in rainfall downstream of the South American low-level jet are identified and compared to those in the South Atlantic convergence zone (SACZ). Composites of precipitation associated with strong jets reveal an approximate doubling of the quantities one would expect from climatology, with an evolution of the rainfall pattern from south to north. The occurrence of extreme precipitation events follows a similar pattern. Meridional cross sections of composite wind reveal a distinct low-level jet near 208S and a baroclinic development farther south that appears to force the jet. Geopotential height, temperature, and large-scale wind composites suggest that this developing disturbance is tied to a wave train that originates in the midlatitude Pacific and turns equatorward as it crosses the Andes Mountains. Similar composites based on SACZ rainfall reveal similar features, but of opposite sign, suggesting that the phase of the wave as it crosses the Andes Mountains determines whether rainfall will be enhanced downstream of the jet or in the SACZ. The alternate suppression or enhancement of rainfall in these adjacent regions results in a precipitation ‘‘dipole.’’ Many previous studies have found a similar out-of-phase relationship over many time scales. The phase of the Madden–Julian oscillation (MJO) is composited relative to anomalous precipitation events, revealing statistically relevant amplitudes associated with rainfall both downstream of the jet and in the SACZ. The MJO is a particularly interesting intraseasonal oscillation because it has some predictability. It is speculated that the slowly varying dipole that has been observed is a consequence of the preferred phasing of synoptic waves due to variations of the planetary-scale basic-state flow, which is at times associated with the MJO.Fil: Liebmann, Brant. National Ocean And Atmospheric Administration; Estados UnidosFil: Kiladis, George. National Ocean And Atmospheric Administration; Estados UnidosFil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Saulo, Andrea Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Carvalho, Leila. Universidade de Sao Paulo; BrasilAmer Meteorological Soc2004-10info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/182457Liebmann, Brant; Kiladis, George; Vera, Carolina Susana; Saulo, Andrea Celeste; Carvalho, Leila; Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone; Amer Meteorological Soc; Journal Of Climate; 17; 19; 10-2004; 3829-38420894-8755CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://journals.ametsoc.org/view/journals/clim/17/19/1520-0442_2004_017_3829_svoris_2.0.co_2.xmlinfo:eu-repo/semantics/altIdentifier/doi/10.1175/1520-0442(2004)017%3C3829:SVORIS%3E2.0.CO;2info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T10:07:42Zoai:ri.conicet.gov.ar:11336/182457instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 10:07:42.462CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
title Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
spellingShingle Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
Liebmann, Brant
SOUTH AMERICA
ANDES
RAINFALL
title_short Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
title_full Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
title_fullStr Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
title_full_unstemmed Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
title_sort Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone
dc.creator.none.fl_str_mv Liebmann, Brant
Kiladis, George
Vera, Carolina Susana
Saulo, Andrea Celeste
Carvalho, Leila
author Liebmann, Brant
author_facet Liebmann, Brant
Kiladis, George
Vera, Carolina Susana
Saulo, Andrea Celeste
Carvalho, Leila
author_role author
author2 Kiladis, George
Vera, Carolina Susana
Saulo, Andrea Celeste
Carvalho, Leila
author2_role author
author
author
author
dc.subject.none.fl_str_mv SOUTH AMERICA
ANDES
RAINFALL
topic SOUTH AMERICA
ANDES
RAINFALL
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Regional and large-scale circulation anomalies associated with variations in rainfall downstream of the South American low-level jet are identified and compared to those in the South Atlantic convergence zone (SACZ). Composites of precipitation associated with strong jets reveal an approximate doubling of the quantities one would expect from climatology, with an evolution of the rainfall pattern from south to north. The occurrence of extreme precipitation events follows a similar pattern. Meridional cross sections of composite wind reveal a distinct low-level jet near 208S and a baroclinic development farther south that appears to force the jet. Geopotential height, temperature, and large-scale wind composites suggest that this developing disturbance is tied to a wave train that originates in the midlatitude Pacific and turns equatorward as it crosses the Andes Mountains. Similar composites based on SACZ rainfall reveal similar features, but of opposite sign, suggesting that the phase of the wave as it crosses the Andes Mountains determines whether rainfall will be enhanced downstream of the jet or in the SACZ. The alternate suppression or enhancement of rainfall in these adjacent regions results in a precipitation ‘‘dipole.’’ Many previous studies have found a similar out-of-phase relationship over many time scales. The phase of the Madden–Julian oscillation (MJO) is composited relative to anomalous precipitation events, revealing statistically relevant amplitudes associated with rainfall both downstream of the jet and in the SACZ. The MJO is a particularly interesting intraseasonal oscillation because it has some predictability. It is speculated that the slowly varying dipole that has been observed is a consequence of the preferred phasing of synoptic waves due to variations of the planetary-scale basic-state flow, which is at times associated with the MJO.
Fil: Liebmann, Brant. National Ocean And Atmospheric Administration; Estados Unidos
Fil: Kiladis, George. National Ocean And Atmospheric Administration; Estados Unidos
Fil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina
Fil: Saulo, Andrea Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina
Fil: Carvalho, Leila. Universidade de Sao Paulo; Brasil
description Regional and large-scale circulation anomalies associated with variations in rainfall downstream of the South American low-level jet are identified and compared to those in the South Atlantic convergence zone (SACZ). Composites of precipitation associated with strong jets reveal an approximate doubling of the quantities one would expect from climatology, with an evolution of the rainfall pattern from south to north. The occurrence of extreme precipitation events follows a similar pattern. Meridional cross sections of composite wind reveal a distinct low-level jet near 208S and a baroclinic development farther south that appears to force the jet. Geopotential height, temperature, and large-scale wind composites suggest that this developing disturbance is tied to a wave train that originates in the midlatitude Pacific and turns equatorward as it crosses the Andes Mountains. Similar composites based on SACZ rainfall reveal similar features, but of opposite sign, suggesting that the phase of the wave as it crosses the Andes Mountains determines whether rainfall will be enhanced downstream of the jet or in the SACZ. The alternate suppression or enhancement of rainfall in these adjacent regions results in a precipitation ‘‘dipole.’’ Many previous studies have found a similar out-of-phase relationship over many time scales. The phase of the Madden–Julian oscillation (MJO) is composited relative to anomalous precipitation events, revealing statistically relevant amplitudes associated with rainfall both downstream of the jet and in the SACZ. The MJO is a particularly interesting intraseasonal oscillation because it has some predictability. It is speculated that the slowly varying dipole that has been observed is a consequence of the preferred phasing of synoptic waves due to variations of the planetary-scale basic-state flow, which is at times associated with the MJO.
publishDate 2004
dc.date.none.fl_str_mv 2004-10
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/182457
Liebmann, Brant; Kiladis, George; Vera, Carolina Susana; Saulo, Andrea Celeste; Carvalho, Leila; Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone; Amer Meteorological Soc; Journal Of Climate; 17; 19; 10-2004; 3829-3842
0894-8755
CONICET Digital
CONICET
url http://hdl.handle.net/11336/182457
identifier_str_mv Liebmann, Brant; Kiladis, George; Vera, Carolina Susana; Saulo, Andrea Celeste; Carvalho, Leila; Subseasonal Variations of Rainfall in South America in the Vicinity of the Low-Level Jet East of the Andes and Comparison to Those in the South Atlantic Convergence Zone; Amer Meteorological Soc; Journal Of Climate; 17; 19; 10-2004; 3829-3842
0894-8755
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://journals.ametsoc.org/view/journals/clim/17/19/1520-0442_2004_017_3829_svoris_2.0.co_2.xml
info:eu-repo/semantics/altIdentifier/doi/10.1175/1520-0442(2004)017%3C3829:SVORIS%3E2.0.CO;2
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
dc.publisher.none.fl_str_mv Amer Meteorological Soc
publisher.none.fl_str_mv Amer Meteorological Soc
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.13397

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