@MastersThesis{Silva:2005:InVóCi,
author = "Silva, L{\'{\i}}gia Alves da",
title = "A influ{\^e}ncia do v{\'o}rtice cicl{\^o}nico de altos
n{\'{\i}}veis (VCAN) sobre a precipita{\c{c}}{\~a}o do
nordeste do Brasil (NEB) e as caracter{\'{\i}}sticas
associadas",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2005",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2005-08-29",
keywords = "v{\'o}rtice cicl{\^o}nico de altos n{\'{\i}}veis, c{\^o}vados
de altos n{\'{\i}}veis, precipita{\c{c}}{\~a}o, regi{\~a}o
Nordeste (Brasil), sistemas cicl{\^o}nicos, high levelss vortex
cyclonic, high levels depression, precipition, Northwest region
(Brasil), cyclonic systems.",
abstract = "Os sistemas cicl{\^o}nicos de altos n{\'{\i}}veis, V{\'o}rtice
Cicl{\^o}nico de Altos n{\'{\i}}veis e Cavados de Altos
N{\'{\i}}veis (VCAN/CAN) sobre o Nordeste do Brasil (NEB) e
oceano adjacente exercem grande influ{\^e}ncia na
precipita{\c{c}}{\~a}o de diferentes sub-regi{\~o}es do NEB no
per{\'{\i}}odo de ver{\~a}o austral. S{\~a}o analisadas as
caracter{\'{\i}}sticas e ocorr{\^e}ncia dos VCAN/ CAN sobre e
pr{\'o}ximo ao NEB para 7 ver{\~o}es de 1994 2001. S{\~a}o
estudadas as influ{\^e}ncias dos VCAN/CAN sobre tr{\^e}s
sub-regi{\~o}es distintas e importantes do NEB (noroeste do NEB e
interior do estado da Bahia e do semi-{\'a}rido), focalizando o
estudo em tr{\^e}s {\'a}reas alvo dentro destas
sub-regi{\~o}es. Os VCAN/CAN apresentam alta variabilidade
interanual na frequ{\^e}ncia de ocorr{\^e}ncia e intensidade.
Estes sistemas t{\^e}m intensidade m{\'e}dia de -5x10-5s-1 e
extens{\~a}o horizontal de 2.000.000 km2 vistos atrav{\'e}s das
cartas de vorticidade (\ζ < -2,5x10-5s-1) em 200 hPa. As
tr{\^e}s sub-regi{\~o}es consideradas s{\~a}o influenciadas
pelos VCAN/CAN, apresentando redu{\c{c}}{\~a}o de
precipita{\c{c}}{\~a}o di{\'a}ria quando est{\~a}o diretamente
sobre a sub-regi{\~a}o em quest{\~a}o, conforme o resultado de
Kousky e Gan (1981), a subsid{\^e}ncia no centro dos VCAN/CAN
posicionada sobre regi{\~o}es inibe a precipita{\c{c}}{\~a}o.
Quando os VCAN/CAN est{\~a}o distantes da sub-regi{\~a}o entre
1000 km 2000 km, nos setores nordeste, leste e sudeste em
rela{\c{c}}{\~a}o {\`a} sub-regi{\~a}o em quest{\~a}o, a
frequ{\^e}ncia de chuva forte aumenta substancialmente devido o
efeito da banda de nebulosidade convectiva na borda, posicionar-se
a oeste do sistema. Quando a dist{\^a}ncia {\'e} menor que 1000
km o efeito da banda convectiva {\'e} marginal e quando {\'e}
maior que 2000 km o efeito dos VCAN/CAN tamb{\'e}m {\'e}
reduzido. Os balan{\c{c}}os de vorticidade nos tr{\^e}s casos de
VCAN revelam que o termo de diverg{\^e}ncia {\'e} dominante nos
est{\'a}gios de intensifica{\c{c}}{\~a}o e dacaimento. Como
esperado, o efeito \β {\'e} significativo e a
advec{\c{c}}{\~a}o de \ζ mostra um papel importante nos
lados leste e oeste dos v{\'o}rtices. Os VCAN/CAN tem
dura{\c{c}}{\~a}o de aproximadamente 10 dias e se deslocam
principalmente do Atl{\^a}ntico para noroeste. ABSTRACT: The
Upper Tropospheric Cyclonic circulation Systems (UTCS) over the
Northeast Brazil (NEB) and the adjoing ocean in the austral summer
have a strong influence on the rainfall over different subregions
of NEB. The occurrence and the characteristics of the UTCS over
and near NEB in the 7 summers from 1994-2001 are examined. The
influence of the UTCS over the three important and distinct
subregions of NEB namely, the northwestern part of NEB, northern
part of Bahia state and the semiarid interior of the Northest, are
studied (by focusing the study on three target areas within the
subregions). The interanual variability is quite high in the
frequency and the intensity of the UTCS. The UTCS on the average,
have an intensity of -5x10-5 s-1 and horizontal extent of
2.000.000 km2 as seen from the vorticity (\ζ< -2.5x10-5 s-1)
charts at 200 hPa. The three subregions considered are influenced
by the UTCS with reduction of daily precipitation when the UTCS is
directly over the subregion considered, confirming the result of
Kousky and Gan (1981) that the subsidence in the center of UTCS
over these regions inhibits precipitation. When the UTCS is far
from the subregion in the northeastern, eastern and southeastern
sectors in relation to the subregion within 1000 and 2000 km
distance, the frequency of mode rate to intense rainfall increases
substantially due to the effect of the convective cloud band near
the border of the system in its western sector. When the distance
is less than 1000 km the effect of the convective band is marginal
and when the distance is greater than 2000 km the effect of the
UTCS is reduced. The vorticity balance for three cases of UTCS
revealed that divergence term is dominant, both in the formative
stage and the dissipative stage. As is expected, for larger UTCS
the effect of \β is significant and the advection of
\ζ plays an important role on the western and eastern sides
of the vortex. The life of UTCS has duration of about 10 days and
they mostely move to northweast from the Atlantic.",
committee = "Gan, Manoel Alonso (presidente) and Satyamurty, Prakki
(orientador) and Cavalcanti, Iracema Fonseca de Albuquerque and
Gandu, Adilson Wagner",
copyholder = "SID/SCD",
englishtitle = "The influence of upper tropospheric cyclonic vortex (UTCV) on the
rainfall over the Northeast Brazil (NEB) and the caracteristics
associates",
language = "pt",
pages = "134",
ibi = "6qtX3pFwXQZGivnJSY/HTbGp",
url = "http://urlib.net/ibi/6qtX3pFwXQZGivnJSY/HTbGp",
targetfile = "paginadeacesso.html",
urlaccessdate = "11 maio 2024"
}