Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season

Chaco jet events (CJEs) are a subset of South American low-level jet events to the east of the Andes, characterized by enhanced poleward penetration and by a strong impact on precipitation over southeastern South America. The present study uses the Eta model short range weather forecasts produced op...

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Autores principales: Nicolini, M., Saulo, A.C.
Formato: JOUR
Materias:
climate modeling
climate oscillation
convection
diurnal variation
jet stream
precipitation assessment
precipitation intensity
radiative forcing
Andes
Argentina
Brazil
South America
Uruguay
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01777971_v94_n1-4_p129_Nicolini
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_01777971_v94_n1-4_p129_Nicolini
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spelling todo:paper_01777971_v94_n1-4_p129_Nicolini2023-10-03T15:08:07Z Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season Nicolini, M. Saulo, A.C. climate modeling climate oscillation convection diurnal variation jet stream precipitation assessment precipitation intensity radiative forcing Andes Argentina Brazil South America Uruguay Chaco jet events (CJEs) are a subset of South American low-level jet events to the east of the Andes, characterized by enhanced poleward penetration and by a strong impact on precipitation over southeastern South America. The present study uses the Eta model short range weather forecasts produced operationally in the Brazilian Center for Weather Forecasts and Climate Studies (Centro de Previsão de Tempo e Estudos Climáticos, CPTEC) to characterize the CJEs and the related precipitation during the 1997-1998 warm season. An enhanced diurnal cycle in precipitation with respect to that found during the warm season mean can be recognized during CJEs in Eta/CPTEC model output, with preference for a nocturnal maximum over southern Brazil, Uruguay, and the central part of northern Argentina, and a daytime maximum near high topography (northwestern Argentina, the Brazilian Planalto). The analysis of thermodynamic and dynamic forcing appearing during CJEs, helps to explain the modeled precipitation cycle: the nocturnal maximum is mostly explained by enhanced low-level convergence at night, while the diurnal one is mainly a response to radiative warming. Boundary-layer convergence, and convective instability, present within the CJEs environment, work together to provide both dynamic forcing and potential for convection. The simulated precipitation cycle is complemented with surface observations of "current weather" that corroborate the main oscillations found in simulated precipitation. © Springer-Verlag 2006. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01777971_v94_n1-4_p129_Nicolini
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic climate modeling
climate oscillation
convection
diurnal variation
jet stream
precipitation assessment
precipitation intensity
radiative forcing
Andes
Argentina
Brazil
South America
Uruguay
spellingShingle climate modeling
climate oscillation
convection
diurnal variation
jet stream
precipitation assessment
precipitation intensity
radiative forcing
Andes
Argentina
Brazil
South America
Uruguay
Nicolini, M.
Saulo, A.C.
Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
topic_facet climate modeling
climate oscillation
convection
diurnal variation
jet stream
precipitation assessment
precipitation intensity
radiative forcing
Andes
Argentina
Brazil
South America
Uruguay
description Chaco jet events (CJEs) are a subset of South American low-level jet events to the east of the Andes, characterized by enhanced poleward penetration and by a strong impact on precipitation over southeastern South America. The present study uses the Eta model short range weather forecasts produced operationally in the Brazilian Center for Weather Forecasts and Climate Studies (Centro de Previsão de Tempo e Estudos Climáticos, CPTEC) to characterize the CJEs and the related precipitation during the 1997-1998 warm season. An enhanced diurnal cycle in precipitation with respect to that found during the warm season mean can be recognized during CJEs in Eta/CPTEC model output, with preference for a nocturnal maximum over southern Brazil, Uruguay, and the central part of northern Argentina, and a daytime maximum near high topography (northwestern Argentina, the Brazilian Planalto). The analysis of thermodynamic and dynamic forcing appearing during CJEs, helps to explain the modeled precipitation cycle: the nocturnal maximum is mostly explained by enhanced low-level convergence at night, while the diurnal one is mainly a response to radiative warming. Boundary-layer convergence, and convective instability, present within the CJEs environment, work together to provide both dynamic forcing and potential for convection. The simulated precipitation cycle is complemented with surface observations of "current weather" that corroborate the main oscillations found in simulated precipitation. © Springer-Verlag 2006.
format JOUR
author Nicolini, M.
Saulo, A.C.
author_facet Nicolini, M.
Saulo, A.C.
author_sort Nicolini, M.
title Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
title_short Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
title_full Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
title_fullStr Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
title_full_unstemmed Modeled Chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
title_sort modeled chaco low-level jets and related precipitation patterns during the 1997-1998 warm season
url http://hdl.handle.net/20.500.12110/paper_01777971_v94_n1-4_p129_Nicolini
work_keys_str_mv AT nicolinim modeledchacolowleveljetsandrelatedprecipitationpatternsduringthe19971998warmseason
AT sauloac modeledchacolowleveljetsandrelatedprecipitationpatternsduringthe19971998warmseason
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