@PhDThesis{ObregónPárraga:2003:DiVaCl,
author = "Obreg{\'o}n P{\'a}rraga, Guillermo Oswaldo",
title = "Din{\^a}mica da variabibilidade clim{\'a}tica da
precipita{\c{c}}{\~a}o sobre a Am{\'e}rica do Sul",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2003",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2001-03-27",
keywords = "variabilidade clim{\'a}tica, an{\'a}lise estat{\'{\i}}stica,
precipita{\c{c}}{\~a}o, mudan{\c{c}}a clim{\'a}tica.",
abstract = "A variabilidade clim{\'a}tica da precipita{\c{c}}{\~a}o em
escalas intrasazonais, sobre o Brasil, e escalas interanual e
per{\'{\i}}odos maiores sobre a Am{\'e}rica do Sul foram
estudadas atrav{\'e}s da utiliza{\c{c}}{\~a}o de dados de
precipita{\c{c}}{\~a}o di{\'a}ria (1979-1990) e mensal
(1951-1990) utilizando diversos m{\'e}todos
estat{\'{\i}}sticos. Os resultados obtidos mostram que a
variabilidade da precipita{\c{c}}{\~a}o sobre a AS, em escalas
sazonal e interanual apresenta caracter{\'{\i}}sticas regionais
intr{\'{\i}}nsecas, com ciclo anual proeminente e persistente
sobre a maior parte do dom{\'{\i}}nio. O ciclo semi-anual {\'e}
predominante principalmente sobre o norte da Amaz{\^o}nia, com
alta persist{\^e}ncia, e sul do Brasil com baixa
persist{\^e}ncia. A distribui{\c{c}}{\~a}o sazonal da
precipita{\c{c}}{\~a}o m{\'e}dia e as estat{\'{\i}}sticas
probabil{\'{\i}}sticas est{\~a}o intensamente relacionadas
durante todas as esta{\c{c}}{\~o}es do ano. Com
rela{\c{c}}{\~a}o {\`a} variabilidade intrasazonal sobre o
Brasil foi encontrado o predom{\'{\i}}nio de
oscila{\c{c}}{\~o}es com per{\'{\i}}odo de 20 e 40 dias, com
caracter{\'{\i}}sticas distintas. A oscila{\c{c}}{\~a}o de 20
dias aparentemente mostra maior depend{\^e}ncia das ondas
barocl{\'{\i}}nicas, enquanto que a de 40 dias parece mais
relacionada com oscila{\c{c}}{\~o}es de escala global e,
possivelmente, interage com maior intensidade com a atmosfera
tropical. Quanto {\`a} variabilidade interanual nota-se que a
precipita{\c{c}}{\~a}o sobre a Am{\'e}rica do Sul {\'e}
modulada pelo El Niño/Oscila{\c{c}}{\~a}o Sul (ENOS), por{\'e}m
esta modula{\c{c}}{\~a}o aparece em dois per{\'{\i}}odos
distintos, de 3,7 e 5 anos. A oscila{\c{c}}{\~a}o de 5 anos tem
predom{\'{\i}}nio sobre as regi{\~o}es equatoriais enquanto que
a oscila{\c{c}}{\~a}o de 3,7 anos tem maior influ{\^e}ncia
sobre o sul do Brasil, ambas moduladas pelo Atl{\^a}ntico
tropical, por{\'e}m com intensidades diferentes. A tend{\^e}ncia
linear e mudan{\c{c}}a clim{\'a}tica sobre a AS apresentam uma
distribui{\c{c}}{\~a}o espa{\c{c}}o-temporal coerentes entre
si. Observou-se tend{\^e}ncia linear negativa da
precipita{\c{c}}{\~a}o anual sobre a faixa de m{\'a}xima
precipita{\c{c}}{\~a}o, associada com a Zona de
Converg{\^e}ncia do Atl{\^a}ntico Sul (ZCAS), e tend{\^e}ncia
positiva sobre o sul do Brasil. Estes padr{\~o}es s{\~a}o
resultado das tend{\^e}ncias negativas intensas concentradas
durante as esta{\c{c}}{\~o}es de ver{\~a}o, na faixa de
m{\'a}xima precipita{\c{c}}{\~a}o, e no sul do Brasil na
primavera. Ambas as tend{\^e}ncias parecem estar associadas
{\`a} mudan{\c{c}}a clim{\'a}tica abrupta observada na metade
da d{\'e}cada de 70, relacionada {\`a} mudan{\c{c}}a da
temperatura superficial do mar (TSM) dos oceanos, principalmente
do Oceano Pac{\'{\i}}fico. Esta mudan{\c{c}}a clim{\'a}tica
abrupta teve repercuss{\~o}es sobre quase toda a Am{\'e}rica do
Sul, com exce{\c{c}}{\~a}o do Nordeste do Brasil, onde a
precipita{\c{c}}{\~a}o apresenta alta variabilidade interanual e
aparente variabilidade quase decadal. ABSTRACT: Intraseasonal
time-scales of climate variability over Brazil, and interannual
and larger time-scales climate variability over South America were
studied using daily (1979- 1990) and monthly (1951-1990) mean
rainfall data and several statistical methods. The results show
that the seasonal and interannual rainfall variability over South
America have intrinsic regional features with prominent and
persistent annual cycle. The semiannual cycle is predominant over
northern Amazon (high persistence) and Southern Brazil (low
persistence). The seasonal mean rainfall distribution is strongly
related to the statistics of probabilities in all seasons. With
respect to intraseasonal variability over Brazil, it was found
that there are two dominant oscillations with periods of 20 and 40
days with distinct characteristics. The 20 day oscillation shows
greater dependence on baroclinic waves, while the 40 day seems to
be more related to the global scale oscillations and apparently
interacts with greater intensity with the tropical atmosphere.
Regarding the interannual variability, it is observed that
precipitation over South America is modulated by El Niño/South
Oscillation (ENSO). However, this modulation is present in the
distinct periods, 3.7 and 5 years. The 5 years oscillation is
predominant over equatorial regions, while the 3.7 years
oscillation is predominant over Southern Brazil. Both are
modulated by Tropical Atlantic, but with different intensities.
The linear trends and climate change over South America show
coherent space-temporal distributions. Negative trends of the
annual precipitation over the maximum rainfall area, related to
the climatological region of the South Atlantic Convergence Zone
(SACZ), and positive trends over Southern Brazil were observed.
These patterns are results of the intense negative tendency
occurred in summer over the maximum rainfall area and during
spring season over Southern Brazil. The trends seem to be
associated with the observed climate change in the mid 70?s, which
is related to the sea surface temperature change, mainly in the
Pacific Ocean. This abrupt climate change affected almost the
whole South America, except Northeast Brazil, where precipitation
shows high interannual variability and apparent quasi-decadal
variability.",
committee = "Rao, Vadlamudi Brahmananda (presidente) and Nobre, Carlos Afonso
(orientador) and Cavalcanti, Iracema Fonseca de Albuquerque and
Ambrizzi, T{\'e}rcio and Morettin, Pedro Alberto",
copyholder = "SID/SCD",
englishtitle = "Rainfall climate variability dynamics over South America",
language = "pt",
ibi = "6qtX3pFwXQZsFDuKxG/xxtn8",
url = "http://urlib.net/ibi/6qtX3pFwXQZsFDuKxG/xxtn8",
targetfile = "publicacao.pdf",
urlaccessdate = "14 maio 2024"
}