@MastersThesis{Barbosa:2007:InPeCo,
author = "Barbosa, Robson Lopes",
title = "Intera{\c{c}}{\~a}o das perturba{\c{c}}{\~o}es convectivas
iniciadas na costa norte do Brasil com os dist{\'u}rbios
ondulat{\'o}rios de leste",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2007",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2005-04-01",
keywords = "linhas de instabilidade, dist{\'u}rbio ondulat{\'o}rio de leste,
tempestade convectiva, perturba{\c{c}}{\~a}o convectiva,
procedimento de acompanhamento, transformada de ondeleta, diagrama
de Hovm{\"o}ller, squall lines, easterly waves disturbance,
convective storm, convective perturbation, tracking method,
wavelet transform, Hovm{\"o}ller diagrams.",
abstract = "Investigaram-se os aspectos climatol{\'o}gicos das
perturba{\c{c}}{\~o}es convectivas (PC) iniciadas na Costa Norte
do Brasil (CNB) e sua rela{\c{c}}{\~a}o com os Dist{\'u}rbios
Ondulat{\'o}rios de Leste (DOL). Utilizou-se dados de
fra{\c{c}}{\~a}o de nuvens convectivas do ISCCP, de 1984 a 1998,
com resolu{\c{c}}{\~o}es horizontal de 2,5o e temporal de 3 h, e
um procedimento objetivo de tracking para obter as sequ{\^e}ncias
de PC. Utilizou-se a componente meridional do vento [nu] em 700
hPa em Bel{\'e}m de 1984 a 1989. As flutua{\c{c}}{\~o}es
interdiurnas foram estudadas por meio da Transformada de Ondeleta
(TO) e de Diagramas de Hovm{\"o}ller. As rela{\c{c}}{\~o}es
entre a propaga{\c{c}}{\~a}o de PC e a{\c{c}}{\~a}o de DOL
foram investigadas somente para o trimestre de MAM
(Mar{\c{c}}o-Abril-Maio). As sequ{\^e}ncias de PC foram
divididas nos tipos pontuais (dura{\c{c}}{\~a}o menor que 3 h) e
n{\~a}o-pontuais (dura{\c{c}}{\~a}o maior que 3 h). As
sequ{\^e}ncias pontuais apresentam tamanhos pequenos e a sua
ocorr{\^e}ncia mostrou menor varia{\c{c}}{\~a}o sazonal do que
as PC n{\~a}o-pontuais. As sequ{\^e}ncias n{\~a}o-pontuais
foram classificadas em fun{\c{c}}{\~a}o de seu deslocamento em:
curtas (confinadas na CNB) e longas. As seq{\"u}{\^e}ncias de PC
n{\~a}o-pontuais apresentaram dire{\c{c}}{\~a}o de
propaga{\c{c}}{\~a}o preferencial para oeste e com
ocorr{\^e}ncia maior (menor) no trimestre MAM (SON)
(Setembro-Outubro-Novembro). As sequ{\^e}ncias n{\~a}o-pontuais
longas possuem tamanho e dura{\c{c}}{\~a}o maiores. Mostrou-se
que em MAM h{\'a} ocorr{\^e}ncia de DOL em 2 a 3
per{\'{\i}}odos. Os resultados mostram que os DOL n{\~a}o
s{\~a}o os {\'u}nicos mecanismos para a propaga{\c{c}}{\~a}o
de PC continente adentro em MAM. Em torno de 60% dos casos de PC
que se propagaram acima de 450 km, houve a a{\c{c}}{\~a}o de DOL
associada a flutua{\c{c}}{\~o}es de 3-9 dias na fase de
inicia{\c{c}}{\~a}o da PC na CNB. Esse percentual tamb{\'e}m
{\'e} v{\'a}lido para PC pontuais, o que sugere a
exist{\^e}ncia de um processo de sele{\c{c}}{\~a}o quando
ocorre a a{\c{c}}{\~a}o de flutua{\c{c}}{\~o}es interdiurnas.
Assim, prop{\~o}e-se o seguinte modelo conceitual: dada uma PC no
CNB, iniciada por fatores locais (aquecimento e brisa
mar{\'{\i}}tima), se a convec{\c{c}}{\~a}o {\'e}
intensificada por alguma for{\c{c}}ante de grande escala (por
exemplo, DOL), ent{\~a}o a PC ganha grande extens{\~a}o
horizontal e se propaga continente adentro. ABSTRACT: The
climatological features of the convective perturbations (CP)
initiated in the northern coast of Brazil (NCB) and the relation
between CP and easterly waves (EW) were studied. ISCCP convective
cloud fraction data from 1984 to 1998 and with horizontal
(temporal) resolution of 2.5° (3 h) were used, and an objective
tracking procedure was developed to obtain the CP sequences. The
meridional wind [nu] at 700 hPa for Bel{\'e}m from 1984 to 1989
was used. The interdiurnal variability were studied by using the
wavelet transform and Hovm{\"o}ller diagrams. The relation
between CP inland propagation and EW activity was investigated
only for MAM (March, April and May). The CP sequences were
classified in single (SI) and multi-image (MI) sequences. SI
sequences take place in a single satellite image (i.e., its
lifetime is less than 3 h). The SI sequences had smaller size and
their occurrence showed smaller seasonal variation than MI
sequences. In general, MI sequences showed westward propagation
and greater (smaller) occurrence in MAM (SON, September, October
and November). The longer MI sequences had greater size and
duration. It was shown that, on average, there was EW activity in
2 to 3 periods in MAM. In about 60% of CP sequences whose
propagation is greater than 450 km, there was 3-9 day EW activity
during the initiation of the sequences. This result is also valid
to sequences that showed negligible propagation. We proposed the
following conceptual model: for a given CP in NCB, initiated by
local forcings (diurnal heating and breeze), if convection is
enhanced by large scale synotic systems (e.g., EW), then the CP
increases in size and propagates inland.",
committee = "Moscati, Marley Cavalcante de Lima (presidente) and Oyama, Marcos
Daisuke (orientador) and Machado, Luiz Augusto Toledo (orientador)
and Angelis, Carlos Frederico de and Gandu, Adilson Wagner",
copyholder = "SID/SCD",
englishtitle = "Interaction of the convective perturbations initiated in the
northern coast of Brazil with the easterly waves",
language = "pt",
pages = "151",
ibi = "6qtX3pFwXQZ3P8SECKy/GFn7T",
url = "http://urlib.net/ibi/6qtX3pFwXQZ3P8SECKy/GFn7T",
targetfile = "publicacao.pdf",
urlaccessdate = "06 maio 2024"
}