The Northwestern Argentinean Low: A Study of Two Typical Events
- Autores
- Seluchi, Marcelo Enrique; Saulo, Andrea Celeste; Nicolini, Matilde; Satyamurty, Prakki
- Año de publicación
- 2003
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- A low pressure system [known as the northwestern Argentinean low (NAL)] is commonly observed over northwestern Argentina near the Andean slopes. This study describes two NAL episodes for summer and winter, with emphasis on the characterization of their three-dimensional structure and temporal variability. With the aid of a high-resolution regional model [Eta/Centro de Previsa˜o de Tempo e Estudos Clima´ticos (CPTEC)], the main mechanisms involved in the NAL life cycle were studied in order to examine how the thermal topographical processes influenced the system behavior. Surface pressure changes in the NAL are mostly dominated by the 600–900-hPa thickness variability, suggesting its thermal character. Based on this result, the temperature tendency equation has been used to quantify all the contributions to thermal changes. The summer NAL has a significant diurnal cycle that has been dominated by surface warming. This single mechanism can explain the low pressure system formation by itself, suggesting that the NAL could always be present during this season unless an adverse process counteracts the positive contribution by the surface sensible heat flux. Other favoring processes found in the analyzed cases were the Foehn effect (warming by subsidence) and the latent heat release. The intermittent behavior of the NAL is associated with a suppression of net warming in the 600–900-hPa layer, due to a cold-air outbreak. In the winter case, the Foehn effect has been mainly responsible for the NAL development. This mechanism acts in connection with an upper-level cyclonic disturbance approaching the Andes, indicating that the thermal response is triggered by a dynamical forcing. As the Foehn effect (locally known as Zonda wind) is a frequent winter phenomenon, the NAL intermittence during this season could be related to transient baroclinic activity, which modulates both the intensification and the decay stages. The NAL has been regarded as a thermal-orographic system. This study suggests that the analyzed NALs behave as an almost ‘‘pure’’ surface thermally driven low in summer, while dynamical-orographic forcing is the organizing mechanism in winter.
Fil: Seluchi, Marcelo Enrique. 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. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil
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: Nicolini, Matilde. 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: Satyamurty, Prakki. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil - Materia
-
ARGENTINA
NORTHWESTERN
NAL - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/182458
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The Northwestern Argentinean Low: A Study of Two Typical EventsSeluchi, Marcelo EnriqueSaulo, Andrea CelesteNicolini, MatildeSatyamurty, PrakkiARGENTINANORTHWESTERNNALhttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1A low pressure system [known as the northwestern Argentinean low (NAL)] is commonly observed over northwestern Argentina near the Andean slopes. This study describes two NAL episodes for summer and winter, with emphasis on the characterization of their three-dimensional structure and temporal variability. With the aid of a high-resolution regional model [Eta/Centro de Previsa˜o de Tempo e Estudos Clima´ticos (CPTEC)], the main mechanisms involved in the NAL life cycle were studied in order to examine how the thermal topographical processes influenced the system behavior. Surface pressure changes in the NAL are mostly dominated by the 600–900-hPa thickness variability, suggesting its thermal character. Based on this result, the temperature tendency equation has been used to quantify all the contributions to thermal changes. The summer NAL has a significant diurnal cycle that has been dominated by surface warming. This single mechanism can explain the low pressure system formation by itself, suggesting that the NAL could always be present during this season unless an adverse process counteracts the positive contribution by the surface sensible heat flux. Other favoring processes found in the analyzed cases were the Foehn effect (warming by subsidence) and the latent heat release. The intermittent behavior of the NAL is associated with a suppression of net warming in the 600–900-hPa layer, due to a cold-air outbreak. In the winter case, the Foehn effect has been mainly responsible for the NAL development. This mechanism acts in connection with an upper-level cyclonic disturbance approaching the Andes, indicating that the thermal response is triggered by a dynamical forcing. As the Foehn effect (locally known as Zonda wind) is a frequent winter phenomenon, the NAL intermittence during this season could be related to transient baroclinic activity, which modulates both the intensification and the decay stages. The NAL has been regarded as a thermal-orographic system. This study suggests that the analyzed NALs behave as an almost ‘‘pure’’ surface thermally driven low in summer, while dynamical-orographic forcing is the organizing mechanism in winter.Fil: Seluchi, Marcelo Enrique. 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. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; BrasilFil: 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: Nicolini, Matilde. 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: Satyamurty, Prakki. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; BrasilAmer Meteorological Soc2003-10info: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/11336/182458Seluchi, Marcelo Enrique; Saulo, Andrea Celeste; Nicolini, Matilde; Satyamurty, Prakki; The Northwestern Argentinean Low: A Study of Two Typical Events; Amer Meteorological Soc; Monthly Weather Review; 131; 10; 10-2003; 2361-23780027-0644CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://journals.ametsoc.org/view/journals/mwre/131/10/1520-0493_2003_131_2361_tnalas_2.0.co_2.xmlinfo:eu-repo/semantics/altIdentifier/doi/10.1175/1520-0493(2003)131%3C2361:TNALAS%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 Técnicas2025-09-29T09:46:04Zoai:ri.conicet.gov.ar:11336/182458instacron: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:34982025-09-29 09:46:04.604CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
The Northwestern Argentinean Low: A Study of Two Typical Events |
title |
The Northwestern Argentinean Low: A Study of Two Typical Events |
spellingShingle |
The Northwestern Argentinean Low: A Study of Two Typical Events Seluchi, Marcelo Enrique ARGENTINA NORTHWESTERN NAL |
title_short |
The Northwestern Argentinean Low: A Study of Two Typical Events |
title_full |
The Northwestern Argentinean Low: A Study of Two Typical Events |
title_fullStr |
The Northwestern Argentinean Low: A Study of Two Typical Events |
title_full_unstemmed |
The Northwestern Argentinean Low: A Study of Two Typical Events |
title_sort |
The Northwestern Argentinean Low: A Study of Two Typical Events |
dc.creator.none.fl_str_mv |
Seluchi, Marcelo Enrique Saulo, Andrea Celeste Nicolini, Matilde Satyamurty, Prakki |
author |
Seluchi, Marcelo Enrique |
author_facet |
Seluchi, Marcelo Enrique Saulo, Andrea Celeste Nicolini, Matilde Satyamurty, Prakki |
author_role |
author |
author2 |
Saulo, Andrea Celeste Nicolini, Matilde Satyamurty, Prakki |
author2_role |
author author author |
dc.subject.none.fl_str_mv |
ARGENTINA NORTHWESTERN NAL |
topic |
ARGENTINA NORTHWESTERN NAL |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
A low pressure system [known as the northwestern Argentinean low (NAL)] is commonly observed over northwestern Argentina near the Andean slopes. This study describes two NAL episodes for summer and winter, with emphasis on the characterization of their three-dimensional structure and temporal variability. With the aid of a high-resolution regional model [Eta/Centro de Previsa˜o de Tempo e Estudos Clima´ticos (CPTEC)], the main mechanisms involved in the NAL life cycle were studied in order to examine how the thermal topographical processes influenced the system behavior. Surface pressure changes in the NAL are mostly dominated by the 600–900-hPa thickness variability, suggesting its thermal character. Based on this result, the temperature tendency equation has been used to quantify all the contributions to thermal changes. The summer NAL has a significant diurnal cycle that has been dominated by surface warming. This single mechanism can explain the low pressure system formation by itself, suggesting that the NAL could always be present during this season unless an adverse process counteracts the positive contribution by the surface sensible heat flux. Other favoring processes found in the analyzed cases were the Foehn effect (warming by subsidence) and the latent heat release. The intermittent behavior of the NAL is associated with a suppression of net warming in the 600–900-hPa layer, due to a cold-air outbreak. In the winter case, the Foehn effect has been mainly responsible for the NAL development. This mechanism acts in connection with an upper-level cyclonic disturbance approaching the Andes, indicating that the thermal response is triggered by a dynamical forcing. As the Foehn effect (locally known as Zonda wind) is a frequent winter phenomenon, the NAL intermittence during this season could be related to transient baroclinic activity, which modulates both the intensification and the decay stages. The NAL has been regarded as a thermal-orographic system. This study suggests that the analyzed NALs behave as an almost ‘‘pure’’ surface thermally driven low in summer, while dynamical-orographic forcing is the organizing mechanism in winter. Fil: Seluchi, Marcelo Enrique. 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. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil 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: Nicolini, Matilde. 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: Satyamurty, Prakki. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasil |
description |
A low pressure system [known as the northwestern Argentinean low (NAL)] is commonly observed over northwestern Argentina near the Andean slopes. This study describes two NAL episodes for summer and winter, with emphasis on the characterization of their three-dimensional structure and temporal variability. With the aid of a high-resolution regional model [Eta/Centro de Previsa˜o de Tempo e Estudos Clima´ticos (CPTEC)], the main mechanisms involved in the NAL life cycle were studied in order to examine how the thermal topographical processes influenced the system behavior. Surface pressure changes in the NAL are mostly dominated by the 600–900-hPa thickness variability, suggesting its thermal character. Based on this result, the temperature tendency equation has been used to quantify all the contributions to thermal changes. The summer NAL has a significant diurnal cycle that has been dominated by surface warming. This single mechanism can explain the low pressure system formation by itself, suggesting that the NAL could always be present during this season unless an adverse process counteracts the positive contribution by the surface sensible heat flux. Other favoring processes found in the analyzed cases were the Foehn effect (warming by subsidence) and the latent heat release. The intermittent behavior of the NAL is associated with a suppression of net warming in the 600–900-hPa layer, due to a cold-air outbreak. In the winter case, the Foehn effect has been mainly responsible for the NAL development. This mechanism acts in connection with an upper-level cyclonic disturbance approaching the Andes, indicating that the thermal response is triggered by a dynamical forcing. As the Foehn effect (locally known as Zonda wind) is a frequent winter phenomenon, the NAL intermittence during this season could be related to transient baroclinic activity, which modulates both the intensification and the decay stages. The NAL has been regarded as a thermal-orographic system. This study suggests that the analyzed NALs behave as an almost ‘‘pure’’ surface thermally driven low in summer, while dynamical-orographic forcing is the organizing mechanism in winter. |
publishDate |
2003 |
dc.date.none.fl_str_mv |
2003-10 |
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/11336/182458 Seluchi, Marcelo Enrique; Saulo, Andrea Celeste; Nicolini, Matilde; Satyamurty, Prakki; The Northwestern Argentinean Low: A Study of Two Typical Events; Amer Meteorological Soc; Monthly Weather Review; 131; 10; 10-2003; 2361-2378 0027-0644 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/182458 |
identifier_str_mv |
Seluchi, Marcelo Enrique; Saulo, Andrea Celeste; Nicolini, Matilde; Satyamurty, Prakki; The Northwestern Argentinean Low: A Study of Two Typical Events; Amer Meteorological Soc; Monthly Weather Review; 131; 10; 10-2003; 2361-2378 0027-0644 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/mwre/131/10/1520-0493_2003_131_2361_tnalas_2.0.co_2.xml info:eu-repo/semantics/altIdentifier/doi/10.1175/1520-0493(2003)131%3C2361:TNALAS%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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1844613439480135680 |
score |
13.070432 |