Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study

Abstract Anchieta-Imigrantes System (AIS) is one of Brazil's primary highways, connecting São Paulo to the Port of Santos. In AIS, Operação Comboio (OC) is activated when visibility drops below 100 m. This study investigated the meteorological factors that initiated OC in AIS during 2015 using...

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Main Authors: Brenda Almeida Santos, Rita Yuri Ynoue
Format: Article
Language:English
Published: Sociedade Brasileira de Meteorologia 2025-04-01
Series:Revista Brasileira de Meteorologia
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862025000100205&lng=en&tlng=en
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author Brenda Almeida Santos
Rita Yuri Ynoue
author_facet Brenda Almeida Santos
Rita Yuri Ynoue
author_sort Brenda Almeida Santos
collection DOAJ
description Abstract Anchieta-Imigrantes System (AIS) is one of Brazil's primary highways, connecting São Paulo to the Port of Santos. In AIS, Operação Comboio (OC) is activated when visibility drops below 100 m. This study investigated the meteorological factors that initiated OC in AIS during 2015 using a comprehensive array of data sources, for example, meteorological stations and synoptic charts. In 2015, OC was triggered on 106 days, predominantly in spring, mostly on the Anchieta Highway, and often in the afternoon. Meteorological systems triggering OC were classified as orographic, confined to the Serra do Mar, or non-orographic, involving broader cloudiness or precipitation detected by satellite or radar. Data from Itutinga Meteorological Station helped differentiate between visibility reductions caused by fog or precipitation. Among the 87 OCs studied in 2015, sea breeze (SB) contributed to 38% of cases. Generally, moisture was provided by advection by the SB or the Post-frontal anticyclone, occasionally from precipitating systems associated with frontal passage or thermodynamic instability. Moisture influx combined with temperature drops, induced by SB, post-frontal air, or nocturnal radiation loss, triggered OC.
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spelling doaj-art-e11831497a6e4bbf973edb5089dff0722025-08-20T02:16:19ZengSociedade Brasileira de MeteorologiaRevista Brasileira de Meteorologia1982-43512025-04-014010.1590/0102-778640240038Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case StudyBrenda Almeida Santoshttps://orcid.org/0000-0001-9059-2617Rita Yuri Ynouehttps://orcid.org/0000-0001-5810-2913Abstract Anchieta-Imigrantes System (AIS) is one of Brazil's primary highways, connecting São Paulo to the Port of Santos. In AIS, Operação Comboio (OC) is activated when visibility drops below 100 m. This study investigated the meteorological factors that initiated OC in AIS during 2015 using a comprehensive array of data sources, for example, meteorological stations and synoptic charts. In 2015, OC was triggered on 106 days, predominantly in spring, mostly on the Anchieta Highway, and often in the afternoon. Meteorological systems triggering OC were classified as orographic, confined to the Serra do Mar, or non-orographic, involving broader cloudiness or precipitation detected by satellite or radar. Data from Itutinga Meteorological Station helped differentiate between visibility reductions caused by fog or precipitation. Among the 87 OCs studied in 2015, sea breeze (SB) contributed to 38% of cases. Generally, moisture was provided by advection by the SB or the Post-frontal anticyclone, occasionally from precipitating systems associated with frontal passage or thermodynamic instability. Moisture influx combined with temperature drops, induced by SB, post-frontal air, or nocturnal radiation loss, triggered OC.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862025000100205&lng=en&tlng=enfogmistsea breezeweather conditionsOperação ComboiomesoscalesynopticAnchieta-Imigrantes System
spellingShingle Brenda Almeida Santos
Rita Yuri Ynoue
Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
Revista Brasileira de Meteorologia
fog
mist
sea breeze
weather conditions
Operação Comboio
mesoscale
synoptic
Anchieta-Imigrantes System
title Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
title_full Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
title_fullStr Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
title_full_unstemmed Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
title_short Analysis of Meteorological Factors That Start Operação Comboio in the Anchieta-Imigrantes System in Brazil: Fog Case Study
title_sort analysis of meteorological factors that start operacao comboio in the anchieta imigrantes system in brazil fog case study
topic fog
mist
sea breeze
weather conditions
Operação Comboio
mesoscale
synoptic
Anchieta-Imigrantes System
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862025000100205&lng=en&tlng=en
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