Jatos De Baixos Níveis a Leste Dos Andes: Comparação Entre Duas Reanálises

Santos, Diego Felipe dos; Reboita, Michelle Simões

doi:10.5380/abclima.v22i0.47595

Cited by 10 publications

(11 citation statements)

References 19 publications

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“…Over the LLJ region, the winds are intensified, and positive precipitation anomalies occur toward SSA. As reported in previous studies, there is an increase in the frequency of LLJ in SA during El Niño years, 45,47,49,50 associated with the strengthening of the upper-level subtropical jet over SSA and the SASA due to the Rossby wave train emanating from the equatorial Pacific Ocean. Thus, negative precipitation anomalies tend to occur in the northern sector of SA, while positive anomalies appear in the southern sector, varying in intensity according to the season (Fig.…”

Section: Impacts On South American Climatesupporting

confidence: 75%

“…46 Indeed, Figure 5A from Reboita et al 48 shows a positive correlation between the ONI and cyclone density over SSA. The low-pressure anomalies over SSA can be considered as a feedback mechanism since they contribute to increasing the frequency and intensity of episodes of low-level jets (LLJ), 45,47,49,50 and these, in turn, contribute to strengthening the cyclones. In terms of the Southern Hemisphere, Reboita et al 48 show that the ENSO modulates the cyclone occurrence regions but not the number of occurrences.…”

Section: Impacts On South American Climatementioning

confidence: 99%

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Impacts of teleconnection patterns on South America climate

Reboita

Ambrizzi

Crespo

et al. 2021

Annals of the New York Academy of Sciences

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Oceanic heat sources disturb the atmosphere, which, to come back to its initial state, disperses waves. These waves affect the climate in remote regions, characterizing the teleconnection patterns. In this study, we describe eight teleconnection patterns that affect South America climate: the El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO), the Tropical Atlantic Dipole (TAD), the South Atlantic Dipole (SAD), the Southern Annular Mode (SAM), the Madden-Julian Oscillation (MJO), and the Indian Ocean Dipole (IOD). Precipitation and winds at 850-hPa anomalies, considering these teleconnection patterns in ENSO neutral periods, are also presented. Overall, southeastern South America and the north sector of the North and Northeast regions of Brazil are the most affected areas by the teleconnection patterns. In general, there is a precipitation dipole pattern between these regions during each teleconnection pattern.

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Section: Impacts On South American Climatesupporting

confidence: 75%

Section: Impacts On South American Climatementioning

confidence: 99%

Impacts of teleconnection patterns on South America climate

Reboita

Ambrizzi

Crespo

et al. 2021

Annals of the New York Academy of Sciences

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“…At mid levels (Figure 4a) there is a large-scale anticyclonic circulation, centered on the state of Mato Grosso, resulting from continental warming. Such an anticyclone was also observed, albeit with a different aspect, at 250 hPa (not shown here), which is normally expected for the summer, characterizing the so-called Bolivian High (Satyamurty et al, 1998). At 700 hPa (Figure 4b), about 3000 m high, the flow from the northern region to the southern region of Brazil is observed.…”

Section: Resultssupporting

confidence: 66%

“…However, at low levels the flow was more intense (Figures 4e-f) -at 850 hPa (Figure 5b) the Low Level Jet (LLJ) is observed, although subtly, with its core over the border between Bolivia and Paraguay -which enhances the transport of particles from the Amazon and Pantanal to the south of Brazil. The LLJ is part of the northerly flow from Amazon region to the southern Brazil, intensifying transport of moisture to the region, increasing the chances of precipitation in RS (Marengo and Soares, 2002;Teixeira and Satyamurty 2007;Santos and Reboita, 2018). Martins et al (2018) indicate that LLJ directly influences the transport of aerosols from the central region to the southern Brazil, contributing to the concentration of particulate material on South region.…”

Section: Resultsmentioning

confidence: 99%

Preliminary study on the case of black rain in Rio Grande do Sul, Brazil: A synoptic point of view

Santiago

Santos²,

Cardoso³

et al. 2021

Rev. Bras. Geog. Fis.

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Particles of soot from forest fires are transported by the wind, reaching distant locations and being deposited on the soil through precipitation, which clears the atmosphere, taking suspended particulate matter into its drops. The general circulation over South America indicates the possibility of soot from forest fires in the Amazon and Pantanal to be transported to southern Brazil. The event called “black rain” was observed in the period from 11 to 13 September 2020 at São Francisco de Assis City, in Rio Grande do Sul State (RS), and so this work aims to analyze if there were any anomalies of the flow that favored the occurrence of this event, given that there was a large number of fires in this period. Through ERA5 reanalysis data and GOES-16 satellite images, it was observed that on the three days under study low-level flow to the south of Brazil was more intense than normal, with the Low Level Jet occurrences, and on days 12 and 13 such flow to the south was also observed at 500 hPa. The precipitation was due to the instability of an extended trough from the Northwestern Argentinean Low. Thus, it is believed that there was a contribution from circulation at low and mid levels in the occurrence of black rain over RS.

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“…Durante o verão (DJF), quando a monção está na sua fase ativa, os ventos em baixos níveis transportam umidade da região Amazônica em direção às regiões sudeste e sul do Brasil, frequentemente através do Jato de Baixos Níveis a leste dos Andes (Marengo et al 2004;Marengo et al 2012;Montini, Jones & Carvalho 2019;Santos & Reboita 2018;Zhou & Lau 1998). A convergência de umidade resultante desse processo, associada com a convecção típica da estação de verão, contribui para a formação da Zona de Convergência do Atlântico Sul (ZCAS; Silva et al 2019), sistema responsável por elevados totais de precipitação no verão no sudeste do Brasil (Carvalho, Jones & Liebmann.…”

Section: Introductionunclassified

Projeções Climáticas de Temperatura do Ar e Precipitação para o Estado de São Paulo Utilizando o Modelo Regional RegCM4

Godoy¹,

Gozzo²,

Llopart³

et al. 2021

Anu. Inst. Geoc.

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Este trabalho teve como objetivo avaliar mudanças nos valores de precipitação e temperatura médios sobre o estado de São Paulo (Brasil) e em três índices de extremos climáticos (dias secos consecutivos – CDD, extremos chuvosos – R95p e duração de ondas de calor – HWD), entre o período presente e o final do século XXI, a partir de um modelo climático regional. Foram utilizadas três simulações/projeções do Regional Climate Model (RegCM4) para o clima presente (1995-2014) e futuro (2080-2100), e a análise foi dividida nas estações de verão (DJF) e inverno (JJA). As simulações consideram o cenário mais pessimista de concentração de gases de efeito estufa na atmosfera do IPCC (RCP8.5). Dados observados do Climate Prediction Center (CPC) são utilizados para analisar a destreza das simulações no clima presente da precipitação e da temperatura do ar. No verão, as simulações superestimam a precipitação no litoral, enquanto no inverno a representam mais próxima do observado. Para a temperatura do ar, há subestimativas no litoral sul para ambas as estações do ano. No interior do estado, as temperaturas simuladas no verão são próximas ao observado, já no inverno observa-se superestimativa desta variável. Em relação aos índices climáticos, é observada pouca mudança do CDD para o verão, e um aumento para o inverno, principalmente do interior do estado, enquanto o R95p mostra sinal oposto ao CDD. O HWD apresenta uma diminuição em DJF no interior e um aumento na região litorânea para JJA. O interior de São Paulo é identificado como a região mais suscetível aos dias secos consecutivos e extremos chuvosos, enquanto as ondas de calor apresentam um sinal de aumento mais relevante no sul e faixa leste do estado, durante o inverno.

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Jatos De Baixos Níveis a Leste Dos Andes: Comparação Entre Duas Reanálises

Cited by 10 publications

References 19 publications

Impacts of teleconnection patterns on South America climate

Impacts of teleconnection patterns on South America climate

Preliminary study on the case of black rain in Rio Grande do Sul, Brazil: A synoptic point of view

Projeções Climáticas de Temperatura do Ar e Precipitação para o Estado de São Paulo Utilizando o Modelo Regional RegCM4

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