500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation

The Southern South America climatological 500 hPa relative vorticity mean state was examined using regional objective analyses of 500 hPa geopotential heights provided by the Servicio Meteorologico Nacional of Argentina. The dataset, covering the period June 1983 to July 1987, was stratified into tw...

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Autores principales: Ruiz, N.E., Vargas, W.M.
Formato: JOUR
Materias:
Argentina
Atmospheric circulation
Cyclone
Precipitation assessment
Synoptic meteorology
Vortex
Weather forecasting
atmospheric circulation
cyclone
precipitation assessment
synoptic meteorology
vortex
weather forecasting
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0177798X_v60_n1-4_p77_Ruiz
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_0177798X_v60_n1-4_p77_Ruiz
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spelling todo:paper_0177798X_v60_n1-4_p77_Ruiz2023-10-03T15:08:13Z 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation Ruiz, N.E. Vargas, W.M. Argentina Atmospheric circulation Cyclone Precipitation assessment Synoptic meteorology Vortex Weather forecasting atmospheric circulation cyclone precipitation assessment synoptic meteorology vortex weather forecasting Argentina The Southern South America climatological 500 hPa relative vorticity mean state was examined using regional objective analyses of 500 hPa geopotential heights provided by the Servicio Meteorologico Nacional of Argentina. The dataset, covering the period June 1983 to July 1987, was stratified into two samples: the cold and warm seasons. Mean cyclonic vorticity south of 40°S results in a climatological trough over Patagonia with a northwest-southeast tilt. North of this latitude, mean anticyclonic circulation dominates with the exception of a centre of cyclonic vorticity over the Rio de la Plata (35°S, 56°W). Seasonal changes appear to be small. Relative vorticity frequency distributions were also analysed. The association between precipitation and synoptic-scale features of the mid-troposphere circulation was investigated through vorticity fields. A particular distribution of vorticity anomalies associated with daily precipitation in Buenos Aires is revealed by biserial correlation coefficient fields. In winter, the strongest relationships are found between 35°S and 40°S over the Andes Mountains (minimum significant correlation coefficients indicating a cyclonic vorticity anomaly), and in the south of Brazil and east of Buenos Aires over the Atlantic Ocean down to a latitude of 40°S (maximum correlation coefficients related to anomalously anticyclonic circulation). This shows the preferential position of troughs and ridges that produce precipitation in Buenos Aires on the time scale of a day. In summer, centres of anomalously cyclonic and anticyclonic vorticity associated with precipitation shift slightly southward. For moderate or intense precipitation in Buenos Aires, advection of warm and wet air southwards appears to be more important in winter, while in summer the strong anomalous vorticity gradient north of the negative centre over the Andes Cordillera favours rainfall in Buenos Aires. Fil:Ruiz, N.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vargas, W.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0177798X_v60_n1-4_p77_Ruiz
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Argentina
Atmospheric circulation
Cyclone
Precipitation assessment
Synoptic meteorology
Vortex
Weather forecasting
atmospheric circulation
cyclone
precipitation assessment
synoptic meteorology
vortex
weather forecasting
Argentina
spellingShingle Argentina
Atmospheric circulation
Cyclone
Precipitation assessment
Synoptic meteorology
Vortex
Weather forecasting
atmospheric circulation
cyclone
precipitation assessment
synoptic meteorology
vortex
weather forecasting
Argentina
Ruiz, N.E.
Vargas, W.M.
500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
topic_facet Argentina
Atmospheric circulation
Cyclone
Precipitation assessment
Synoptic meteorology
Vortex
Weather forecasting
atmospheric circulation
cyclone
precipitation assessment
synoptic meteorology
vortex
weather forecasting
Argentina
description The Southern South America climatological 500 hPa relative vorticity mean state was examined using regional objective analyses of 500 hPa geopotential heights provided by the Servicio Meteorologico Nacional of Argentina. The dataset, covering the period June 1983 to July 1987, was stratified into two samples: the cold and warm seasons. Mean cyclonic vorticity south of 40°S results in a climatological trough over Patagonia with a northwest-southeast tilt. North of this latitude, mean anticyclonic circulation dominates with the exception of a centre of cyclonic vorticity over the Rio de la Plata (35°S, 56°W). Seasonal changes appear to be small. Relative vorticity frequency distributions were also analysed. The association between precipitation and synoptic-scale features of the mid-troposphere circulation was investigated through vorticity fields. A particular distribution of vorticity anomalies associated with daily precipitation in Buenos Aires is revealed by biserial correlation coefficient fields. In winter, the strongest relationships are found between 35°S and 40°S over the Andes Mountains (minimum significant correlation coefficients indicating a cyclonic vorticity anomaly), and in the south of Brazil and east of Buenos Aires over the Atlantic Ocean down to a latitude of 40°S (maximum correlation coefficients related to anomalously anticyclonic circulation). This shows the preferential position of troughs and ridges that produce precipitation in Buenos Aires on the time scale of a day. In summer, centres of anomalously cyclonic and anticyclonic vorticity associated with precipitation shift slightly southward. For moderate or intense precipitation in Buenos Aires, advection of warm and wet air southwards appears to be more important in winter, while in summer the strong anomalous vorticity gradient north of the negative centre over the Andes Cordillera favours rainfall in Buenos Aires.
format JOUR
author Ruiz, N.E.
Vargas, W.M.
author_facet Ruiz, N.E.
Vargas, W.M.
author_sort Ruiz, N.E.
title 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
title_short 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
title_full 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
title_fullStr 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
title_full_unstemmed 500 hPa vorticity analyses over Argentina: Their climatology and capacity to distinguish synoptic-scale precipitation
title_sort 500 hpa vorticity analyses over argentina: their climatology and capacity to distinguish synoptic-scale precipitation
url http://hdl.handle.net/20.500.12110/paper_0177798X_v60_n1-4_p77_Ruiz
work_keys_str_mv AT ruizne 500hpavorticityanalysesoverargentinatheirclimatologyandcapacitytodistinguishsynopticscaleprecipitation
AT vargaswm 500hpavorticityanalysesoverargentinatheirclimatologyandcapacitytodistinguishsynopticscaleprecipitation
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