Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation
Cold fronts are the most frequent synoptic systems that affect Southeast Brazil during the whole year. The highest frequency of these systems at these latitudes occurs in the months of spring (SON) and winter (JJA), but the highest associated precipitation occurs in the spring (SON) and summer (DJF)...
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crwiley:10.1002/joc.5744 2024-06-23T07:56:47+00:00 Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation M. Andrade, Kelen F. A. Cavalcanti, Iracema Conselho Nacional de Desenvolvimento Científico e Tecnológico Fundação de Amparo à Pesquisa do Estado de São Paulo 2018 http://dx.doi.org/10.1002/joc.5744 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.5744 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.5744 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor International Journal of Climatology volume 38, issue 14, page 5368-5385 ISSN 0899-8418 1097-0088 journal-article 2018 crwiley https://doi.org/10.1002/joc.5744 2024-06-04T06:44:44Z Cold fronts are the most frequent synoptic systems that affect Southeast Brazil during the whole year. The highest frequency of these systems at these latitudes occurs in the months of spring (SON) and winter (JJA), but the highest associated precipitation occurs in the spring (SON) and summer (DJF). Some of these fronts present light rains but others cause heavy precipitation, giving rise to flooding and landslides, mainly in the summer. Composites of the two cases (light and heavy rainfall) are analysed for the summer season. Large‐scale and regional features are shown to discuss the differences in precipitation. Regional differences are seen in the position and intensity of low pressure and postfrontal high. The differences are also associated with the humidity flux and convergence over the region. The main difference at high levels is the position of the frontal trough, which is close to the region in the wet cases and displaced to the ocean in the dry cases. Features of the Southern Annular Mode and Madden–Julian Oscillation show opposite patterns in the two cases. These modes of variability can modulate extra‐tropical wave trains over the Pacific, which have different behaviour downstream, over South America and South Atlantic Ocean. The eddy kinetic energy is stronger over Southeastern Pacific and Southern South America, and wave activity shows energy propagation towards the continent in the wet cases. Similar analyses with results of a global atmospheric model show that the general atmospheric characteristics of a frontal system are reproduced, as the temperature gradient, the wind confluence and the ridge‐trough pair associated with the frontal system. The model represents the differences with respect to moisture flux and the frontal trough position, but underestimates the moisture convergence, eddy kinetic energy and wave activity, in the wet cases. Article in Journal/Newspaper South Atlantic Ocean Wiley Online Library Pacific International Journal of Climatology 38 14 5368 5385 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Cold fronts are the most frequent synoptic systems that affect Southeast Brazil during the whole year. The highest frequency of these systems at these latitudes occurs in the months of spring (SON) and winter (JJA), but the highest associated precipitation occurs in the spring (SON) and summer (DJF). Some of these fronts present light rains but others cause heavy precipitation, giving rise to flooding and landslides, mainly in the summer. Composites of the two cases (light and heavy rainfall) are analysed for the summer season. Large‐scale and regional features are shown to discuss the differences in precipitation. Regional differences are seen in the position and intensity of low pressure and postfrontal high. The differences are also associated with the humidity flux and convergence over the region. The main difference at high levels is the position of the frontal trough, which is close to the region in the wet cases and displaced to the ocean in the dry cases. Features of the Southern Annular Mode and Madden–Julian Oscillation show opposite patterns in the two cases. These modes of variability can modulate extra‐tropical wave trains over the Pacific, which have different behaviour downstream, over South America and South Atlantic Ocean. The eddy kinetic energy is stronger over Southeastern Pacific and Southern South America, and wave activity shows energy propagation towards the continent in the wet cases. Similar analyses with results of a global atmospheric model show that the general atmospheric characteristics of a frontal system are reproduced, as the temperature gradient, the wind confluence and the ridge‐trough pair associated with the frontal system. The model represents the differences with respect to moisture flux and the frontal trough position, but underestimates the moisture convergence, eddy kinetic energy and wave activity, in the wet cases. |
author2 |
Conselho Nacional de Desenvolvimento Científico e Tecnológico Fundação de Amparo à Pesquisa do Estado de São Paulo |
format |
Article in Journal/Newspaper |
author |
M. Andrade, Kelen F. A. Cavalcanti, Iracema |
spellingShingle |
M. Andrade, Kelen F. A. Cavalcanti, Iracema Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
author_facet |
M. Andrade, Kelen F. A. Cavalcanti, Iracema |
author_sort |
M. Andrade, Kelen |
title |
Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
title_short |
Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
title_full |
Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
title_fullStr |
Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
title_full_unstemmed |
Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation |
title_sort |
atmospheric characteristics that induce extreme precipitation in frontal systems over southeastern brazil during summer: observations and atmospheric model simulation |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1002/joc.5744 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.5744 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.5744 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
International Journal of Climatology volume 38, issue 14, page 5368-5385 ISSN 0899-8418 1097-0088 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/joc.5744 |
container_title |
International Journal of Climatology |
container_volume |
38 |
container_issue |
14 |
container_start_page |
5368 |
op_container_end_page |
5385 |
_version_ |
1802650133345599488 |