@PhDThesis{Ferreira:2013:VaMoAm,
author = "Ferreira, Solange Arag{\~a}o",
title = "Variabilidade da mon{\c{c}}{\~a}o da Am{\'e}rica do Sul",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2013",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2013-02-28",
keywords = "variabilidade, Am{\'e}rica do Sul, precipita{\c{c}}{\~a}o,
mon{\c{c}}{\~a}o, variability, South America, monsoon,
preciptation.",
abstract = "Os per{\'{\i}}odos ativos e inativos do Sistema de
Mon{\c{c}}{\~a}o da Am{\'e}rica Sul (SMAS) foram determinados
com base no {\'{\I}}ndice de Precipita{\c{c}}{\~a}o da
Mon{\c{c}}{\~a}o (IPM) para os tr{\^e}s meses mais {\'u}midos
(DJF). O campo do composto da precipita{\c{c}}{\~a}o para os
casos de per{\'{\i}}odos ativos mostra um padr{\~a}o semelhante
{\`a} precipita{\c{c}}{\~a}o m{\'e}dia de ver{\~a}o. O
composto da circula{\c{c}}{\~a}o dos ventos apresenta um forte
fluxo de noroeste desde o oeste da Amaz{\^o}nia at{\'e} o
sudeste do Brasil. Durante per{\'{\i}}odos ativos (inativos),
uma intensa (fraca) converg{\^e}ncia do fluxo de umidade ocorre
ao longo da bacia amaz{\^o}nica, sudeste e centro-oeste do
Brasil. A intensa converg{\^e}ncia de umidade sobre essas
regi{\~o}es durante os per{\'{\i}}odos ativos {\'e} uma
caracter{\'{\i}}stica t{\'{\i}}pica da Zona de
Converg{\^e}ncia do Atl{\^a}ntico Sul (ZCAS). Diagramas de
Hovm{\"o}ller nas p{\^e}ntadas de ROL, assim como anomalias de
ROL n{\~a}o filtradas e filtradas com m{\'e}dia entre as
latitudes de 0\$°\$ e 10\$°\$S, foram utilizados para
identificar associa{\c{c}}{\~o}es da presen{\c{c}}a ou
aus{\^e}ncia de nebulosidade convectiva com as ondas de Kelvin e
de Rossby equatorial, e a OMJ. Uma oscila{\c{c}}{\~a}o da
convec{\c{c}}{\~a}o na ordem de 10 a 15 dias que foi associada
{\`a} variabilidade da intensidade do anticiclone boliviano, e
outra oscila{\c{c}}{\~a}o associada {\`a} presen{\c{c}}a de
VCANs sobre o Nordeste do Brasil, tamb{\'e}m foram observadas. As
an{\'a}lises da convec{\c{c}}{\~a}o mostraram que na maioria
dos casos a convec{\c{c}}{\~a}o com propaga{\c{c}}{\~a}o para
leste esteve associada {\`a}s ondas de Kelvin. As atividades
convectivas com deslocamento para oeste estiveram associadas
{\`a}s ondas de Rossby. Neste trabalho observou-se as ondas
equatoriais de Rossby e Kelvin interagindo com a
convec{\c{c}}{\~a}o, resultando em deslocamento e
intensifica{\c{c}}{\~a}o da atividade convectiva. A fase
favor{\'a}vel {\`a} convec{\c{c}}{\~a}o da OMJ interagiu com
as ondas equatoriais de Kelvin e de Rossby, e tamb{\'e}m
contribuiu para intensificar a convec{\c{c}}{\~a}o. A
an{\'a}lise da EOF Ciclo Estacion{\'a}ria (CSEOF) foi aplicada
sobre a regi{\~a}o entre 20\$°\$N-60\$°\$S e
0\$°\$-90\$°\$E durante 29 anos, e para diferentes
vari{\'a}veis considerando as 30 primeiras CSEOF. Neste estudo
foram analisados os 3 primeiros modos da CSEOF, onde juntos
explicam um total de variabilidade entre 18 e 70 \%. O primeiro
modo da CSEOF representa o padr{\~a}o ciclo sazonal, o segundo
modo explica a fase fria do ENOS (La Niņa) sobre o Oceano
Pac{\'{\i}}fico Tropical, e o terceiro modo descreve a fase de
transi{\c{c}}{\~a}o do ENOS (de La Niņa para El Niņo) e
poss{\'{\i}}vel atua{\c{c}}{\~a}o da OMJ. Esses padr{\~o}es
mostram uma configura{\c{c}}{\~a}o de propaga{\c{c}}{\~a}o de
trens de onda entre as regi{\~o}es
Indon{\'e}sia/Pac{\'{\i}}fico e Am{\'e}rica do Sul, que
s{\~a}o associados {\`a} intensifica{\c{c}}{\~a}o ou
enfraquecimento da atividade convectiva sobre a regi{\~a}o de
atua{\c{c}}{\~a}o da ZCAS, e regi{\~a}o do SMAS. ABSTRACT: The
active and break periods of the South America monsoon system
(SAMS) were determined based on a monsoon rainfall index (MRI) for
the three wettest months. The precipitation composite for active
cases shows a pattern similar to the average summer rainfall. The
wind circulation composite presents a strong northwesterly flow
from the western Amazon to southeastern Brazil. During active
(break) periods, an intense (weak) moisture flux convergence
occurs over the Amazon Basin, southeastern and central-western
Brazil. The intense moisture convergence over these regions during
the active periods is a typical feature of the South Atlantic
Convergence Zone (SACZ) system. Hovm{\"o}ller diagrams of OLR
pentads, OLR anomalies as well unfiltered and filtered mean
between latitudes 0\$°\$ and 10\$°\$S, were used to identify
associations of the presence or suppression of convective
cloudiness with Kelvin and Rossby equatorial waves, and
Madden-Julian oscillation (MJO). An oscillation of convection in
the order of 10 to 15 days was associated with variability in the
intensity of the Bolivian anticyclone, and other oscillation
associated with the presence of VCANs over northeastern Brazil,
were also observed. The analysis showed that the convection with
eastward displacing was associated with Kelvin waves in most of
the cases. Convective activities with westward displacement were
associated with Rossby waves. In this work was observed the
equatorial Rossby and Kelvin interacting with convection,
resulting in displacement and intensification of convective
activity. The favorable phase to MJO convection interacted with
equatorial Rossby and Kelvin waves, and also contributed to
enhance convection. The favorable phase to convection of the MJO
interacted with the equatorial Kelvin waves, and contributed to
intensify the convection. Cyclostationary Empirical Orthogonal
Function (CSEOF) analysis was applied in the region between
20\$°\$N-60\$°\$S and 0\$°\$-90\$°\$E and for 29 years,
for several variables and considering the first 30 CSEOF. This
study were analyzed only the 3 first modes of CSEOF, which
together explain a total variability around 18 and 70\%. The
first mode represents the CSEOF seasonal cycle, the second mode
explains the cold phase of ENSO (La Niņa), and the third mode
describes the transition phase of ENSO (La Niņa to El Niņo) and
possible interaction of the Madden Julian Oscillation. These
patterns show a configuration propagating wave trains between
regions Indonesia / Pacific and South America, which are
associated with the intensification or weakening of convective
activity over the SACZ and the SAMS regions.",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
committee = "Ferreira, Nelson Jesuz (presidente) and Gan, Manoel Alonso
(orientador) and Cavalcanti, Iracema Fonseca de Albuquerque and
Ambrizzi, T{\'e}rcio and Silva, Adma Raia",
copyholder = "SID/SCD",
englishtitle = "Variability of the South America Monsoon",
language = "pt",
pages = "207",
ibi = "8JMKD3MGP7W/3DSAUJ2",
url = "http://urlib.net/ibi/8JMKD3MGP7W/3DSAUJ2",
targetfile = "publicacao.pdf",
urlaccessdate = "01 maio 2024"
}