@PhDThesis{Fernandes:2018:InEsVa,
author = "Fernandes, Valesca Rodriguez",
title = "Influ{\^e}ncia das escalas de variabilidade sin{\'o}tica,
submensal e intrassazonal nas regi{\~o}es tropicais e
subtropicais da Am{\'e}rica do Sul e oceanos adjacentes",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2018",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2018-05-24",
keywords = "intera{\c{c}}{\~a}o de escalas, intrasazonal, sin{\'o}tica,
submensal, Am{\'e}rica do Sul, Sudeste do Brasil, scales
interaction, intraseasonal, synoptic, submonthly, South America,
Southeastern Brazil.",
abstract = "No intuito de identificar os modos dominantes de variabilidade da
atividade convectiva que atuam nas regi{\~o}es extratropicais e
tropicais da Am{\'e}rica do Sul (AS) e os oceanos adjacentes,
utilizaram-se dois m{\'e}todos de an{\'a}lise: a Transformada de
Ondaletas (TO) e Padr{\~a}o de Oscila{\c{c}}{\~a}o Principal
(POP). Os dados di{\'a}rios de radia{\c{c}}{\~a}o de onda longa
(ROL) foram utilizados como proxies de convec{\c{c}}{\~a}o e
referem-se ao per{\'{\i}}odo de 1979 a 2016. A TO foi aplicada
na s{\'e}rie temporal de ROL com intuito de obter a pot{\^e}ncia
espectral (vari{\^a}ncias) nas escalas sin{\'o}tica, submensal e
intrassazonal. Na escala sin{\'o}tica, observou-se
vari{\^a}ncias mais significativas sobre a regi{\~a}o tropical
associada {\`a} Zona de Converg{\^e}ncia Intertropical (ZCIT),
na regi{\~a}o Sul da AS associadas aos sistemas frontais e ao
longo de regi{\~o}es dominadas por sistemas transientes. Na
escala submensal, observaram-se maiores valores de vari{\^a}ncia
nas regi{\~o}es Centro-oeste e Sudeste do Brasil associado {\`a}
Zona de Converg{\^e}ncia do Atl{\^a}ntico Sul (ZCAS) e,
tamb{\'e}m se observa no Oceano Pac{\'{\i}}fico Oeste, Central
e nordeste da Austr{\'a}lia devido {\`a} atua{\c{c}}{\~a}o da
Zona de Converg{\^e}ncia do Pac{\'{\i}}fico Sul (ZCPS). Na
escala intrassazonal, os maiores valores de vari{\^a}ncia foram
observados no oceano Pac{\'{\i}}fico e na regi{\~a}o Sudeste e
Nordeste da Am{\'e}rica do Sul que podem estar associados {\`a}
presen{\c{c}}a da Oscila{\c{c}}{\~a}o de Madden Julian (OMJ). A
fim de investigar os modos dominantes nas escalas de 10-30 e 30-60
dias sobre a AS e oceanos adjacentes utilizou o m{\'e}todo POP no
per{\'{\i}}odo de ver{\~a}o austral de 2006 a 2016. Os
resultados para a escala submensal mostram que o modo mais
significativo apresenta vari{\^a}ncia de 17,7%. Esse modo {\'e}
caracterizado por um trem de ondas, que se propagam do
Pac{\'{\i}}fico na dire{\c{c}}{\~a}o leste e associa-se a ZCAS
intensificada (suprimida) com supress{\~a}o
(intensifica{\c{c}}{\~a}o) da convec{\c{c}}{\~a}o sobre o Sul
do Brasil. Na escala intrassazonal, a vari{\^a}ncia foi de 19,5%
e observa-se padr{\~a}o oscilat{\'o}rio de onda na regi{\~a}o
do oceano Pac{\'{\i}}fico Leste com propaga{\c{c}}ao para a
regi{\~a}o Sudeste e Nordeste do Brasil. A fim de avaliar os
padr{\~o}es de circula{\c{c}}{\~a}o atmosf{\'e}rica em baixos
e altos n{\'{\i}}veis e ROL foram feitos compostos associados ao
modo dominante do v300/POP. Na escala submensal, observou-se um
dipolo entre a regi{\~a}o da ZCAS (associada a maior
precipita{\c{c}}{\~a}o) e sul do Brasil (associada a menos
precipita{\c{c}}{\~a}o). Na anomalia do vento (altos
n{\'{\i}}veis) destacou-se um padr{\~a}o ondulat{\'o}rio do
oceano Pac{\'{\i}}fico Sul para a AS. Na evolu{\c{c}}{\~a}o
desse padr{\~a}o, pode-se verificar a varia{\c{c}}{\~a}o na
amplitude dos m{\'a}ximos, o que indica propaga{\c{c}}{\~a}o de
energia. No campo m{\'e}dio e anomalia do vento (baixos
n{\'{\i}}veis) observou-se a presen{\c{c}}a dos sistemas
transientes, as altas ASAS e ASPS, circula{\c{c}}{\~a}o do JBN e
converg{\^e}ncia dos ventos associados {\`a} ZCAS,
respectivamente. Na escala intrassazonal, a composi{\c{c}}{\~a}o
do vento (300 hPa) {\'e} similar {\`a} escala submensal,
por{\'e}m diferem na posi{\c{c}}{\~a}o e intensidade dos
sistemas. Na composi{\c{c}}{\~a}o de ROL observou-se
convec{\c{c}}{\~a}o ativa na regi{\~a}o Sudeste do Brasil,
associada {\`a} ZCAS e, tamb{\'e}m, a presen{\c{c}}a da OMJ.
Foram feitas an{\'a}lises da energia cin{\'e}tica (EC) para a
AS, com intuito de analisar poss{\'{\i}}veis
intera{\c{c}}{\~o}es entre os eddies de diferentes escalas de
tempo. Resultados encontrados mostraram que a
distribui{\c{c}}{\~a}o de EC na escala sin{\'o}tica
concentra-se essencialmente em latitudes m{\'e}dias e altas ao
longo das storm tracks. A fonte de energia nessas latitudes
origina-se principalmente da convers{\~a}o barocl{\'{\i}}nica.
Para a escala submensal, a distribui{\c{c}}{\~a}o de EC
concentra-se principalmente no Pac{\'{\i}}fico Sul a oeste dos
Andes. O sinal forte de EC nessa regi{\~a}o {\'e} dominado pela
converg{\^e}ncia do fluxo de energia. Na faixa dos storm tracks
(entre 40º a 50º S) a EC na escala x submensal assemelha-se com o
padr{\~a}o dessa vari{\'a}vel na escala sin{\'o}tica, sendo
dominado pelo termo de convers{\~a}o barocl{\'{\i}}nica dessa
escala. A distribui{\c{c}}{\~a}o de EC no Pac{\'{\i}}fico Sul
para a escala intrassazonal n{\~a}o apresenta um padr{\~a}o bem
definido, ela {\'e} caracterizada por sinais positivos e
negativos. Por outro lado, no sul da AS e oceanos vizinhos
destaca-se sinais positivos a oeste dos Andes e negativos no
Atl{\^a}ntico Sudoeste. Essa configura{\c{c}}{\~a}o
assemelha-se aos campos da convers{\~a}o barocl{\'{\i}}nica e
barotr{\'o}pica, mas com sinais opostos. Assim EC intrassazonal
{\'e} dominada pelo termo de convers{\~a}o do fluxo de energia
que {\'e} forte nessa regi{\~a}o. Desta forma, conclui-se que
h{\'a} intera{\c{c}}{\~a}o de escalas na Am{\'e}rica do Sul e
oceanos adjacentes, por{\'e}m a escala submensal apresenta uma
amplitude maior que as escalas sin{\'o}tica e intrassazonal na
regi{\~a}o sudeste do Brasil. ABSTRACT: In order to identify the
dominant modes of convective activity variability that act in the
extratropics and tropics regions of South America (SA) and the
adjacent oceans, two methods of analysis were used: the Wavelet
Transform (TO) and the Principal Oscillation Pattern (POP). The
daily outgoing longwave radiation (OLR) were used as convection
proxies and refer to the period 1979 to 2016. The TO was applied
in the time series of ROL in order to obtain the global power
spectrum (variance) of synoptic, submonthly and intraseasonal
scales. In the synoptic scale, the wavelet transform showed the
most significant variances on the tropical region associated to
the Intertropical Convergence Zone (ITCZ), in the southern region
of the SA associated with the frontal systems and along regions
dominated by transient systems. In the submonthly scale, the
highest values of variance in the central-west and south-eastern
regions of Brazil associated with the South Atlantic Convergence
Zone (SACZ) were observed, and it is also observed in the Western
Pacific Ocean, Central and Northeastern Australia due to of the
South Pacific Convergence Zone (SPCZ). In the intraseasonal scale,
the highest values of variance were observed in the Pacific Ocean
and in the Southeast and Northeast region of South America that
may be associated with the presence of Madden Julian Oscillation
(MJO). In order to investigate dominant modes at the 10-30 and
30-60 day scales on AS and adjacent oceans used the POP method in
the austral summer period from 2006 to 2016. In the submonthly
scale, the most significant variability mode presents a variance
of 17.1%. These modes are characterized by wave patterns that
propagate from the Pacific in the eastward direction and this wave
pattern seems to associate an intensified (suppressed) SACZ with
suppression (intensification) of convection over southern Brazil.
In the intraseasonal scale, the observed variance was 19.5% and
the same oscillatory wave pattern is observed in the region of the
Eastern Pacific Ocean with propagation to the southeastern and
northeastern region of Brazil. In order to evaluate atmospheric
circulation patterns at low and high levels and OLR, composite
fields associated with the dominant mode of v300 / POP were made.
In the submonthly scale, a dipole was observed between the SACZ
region (associated to the highest precipitation) and southern
Brazil (associated with less precipitation). In the anomaly of the
wind (high levels) we highlighted a wave pattern of the South
Pacific Ocean for AS. In the evolution of this pattern, one can
verify the variation in the amplitude of the maxima, which
indicates propagation of energy. In the mean field and wind
anomaly (low levels) the presence of transient systems, the ASAS
and ASPS highs, the low level jet circulation (LLJ) and the
convergence of the winds associated to the SACZ, respectively,
were observed. In the intraseasonal scale, the composition of the
wind (300 hPa) is similar to the submonthly scale, but they differ
in the position and intensity of the systems. In the OLR
composition, active convection was observed in the southeastern
region of Brazil, xii associated to the SACZ and also the presence
of the MJO. Kinetic energy balance was analyzed for South America
in order to analyze possible interactions between eddies of
different time scales. Results showed that the EC distribution in
the synoptic scale is mainly concentrated in mid and high
latitudes along the storm tracks. The source of energy in these
latitudes comes mainly from the baroclinic conversion. For the
submonthly scale, the EC distribution is mainly concentrated in
the South Pacific west of the Andes. The strong EC signal in this
region is dominated by the energy flux convergence. In the band of
storm tracks (between 40º and 50º S) the EC on the submonthly
scale resembles the standard of this variable in high frequency,
being dominated by the baroclinic conversion term of this scale.
Finally, the distribution of EC in the South Pacific to the
intrastate scale does not present a well-defined pattern, it is
characterized by positive and negative signals. On the other hand,
in the south of the AS and neighboring oceans there are positive
signs to the west of the Andes and negatives in the Southwest
Atlantic. This configuration resembles the baroclinic and
barotropic conversion fields, but with opposing signs. Thus
intraseasonal EC is dominated by the energy flow conversion term
that is strong in that region. In this way, it is concluded that
there is interaction of scales in South America and adjacent
oceans, but the submonthly scale has a greater amplitude than the
synoptic and intreseasonal scales in the southeastern region of
Brazil.",
committee = "Gan, Manoel Alonso (presidente) and Ferreira, Nelson Jesuz
(orientador) and M{\"u}ller, Gabriela Viviana (orientadora) and
Escobar, Gustavo Carlos Juan and Brambila, Mar{\'{\i}}a
Cleof{\'e} Valverde and Corr{\^e}a, Cleber Souza",
englishtitle = "Influence of synoptic, submonthly and intraseasonal variability
scales in the tropical and subtropical regions of South America
and adjacent oceans",
language = "pt",
pages = "174",
ibi = "8JMKD3MGP3W34R/3QLRDCP",
url = "http://urlib.net/ibi/8JMKD3MGP3W34R/3QLRDCP",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}