@MastersThesis{Gomes:2009:EfDi,
author = "Gomes, Francisco",
title = "A influ{\^e}ncia dos aeross{\'o}is na din{\^a}mica da
mon{\c{c}}{\~a}o oeste africana: efeito direto",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2009",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2009-07-03",
keywords = "modelagem, aeross{\'o}is, mon{\c{c}}{\~a}o oeste africana,
precipita{\c{c}}{\~a}o, Africa Ocidental. modeling, aerosols,
West African Monsoon, precipitation, West Africa.",
abstract = "Este estudo visa contribuir para um melhor conhecimento sobre as
interfer{\^e}ncias das componentes radiativas dos aeross{\'o}is
na complexa intera{\c{c}}{\~a}o do sistema acoplado entre a
terra, oceano e atmosfera, do qual resulta a
Configura{\c{c}}{\~a}o da Mon{\c{c}}{\~a}o Oeste Africana. A
pluviometria da {\'A}frica Ocidental depende unicamente da
ativa{\c{c}}{\~a}o desta circula{\c{c}}{\~a}o
mon{\c{c}}{\^o}nica, o que determina a import{\^a}ncia deste
sistema, ao se considerar uma agricultura altamente dependente do
clima e que constitui a base da economia da regi{\~a}o. Neste
estudo foi utilizado o modelo regional clim{\'a}tico (RegCM3)
acoplado com o modelo de poeira e de aerossol antropog{\^e}nico.
Os efeitos dos aeross{\'o}is na circula{\c{c}}{\~a}o
mon{\c{c}}{\^o}nica foram avaliados atrav{\'e}s de
compara{\c{c}}{\~a}o de experimentos com e sem
intera{\c{c}}{\~a}o dos aeross{\'o}is no balan{\c{c}}o
radiativo. As simula{\c{c}}{\~o}es foram integradas para o
per{\'{\i}}odo chuvoso (junho, julho, agosto e setembro) para
tr{\^e}s anos escolhidos dentro da s{\'e}rie (1970-2000): ano
seco (1983); normal (1996) e chuvoso (1978), durante os quais
n{\~a}o houve a ocorr{\^e}ncia do fen{\^o}meno do ENSO. Os
resultados mostraram a redu{\c{c}}{\~a}o da
precipita{\c{c}}{\~a}o sobre a {\'A}frica Ocidental sob efeito
do resfriamento induzido pela carga de poeira no Saara e dos
aeross{\'o}is antropog{\^e}nico. Este resfriamento diminuiu o
gradiente meridional da energia est{\'a}tica {\'u}mida e
resultou no enfraquecimento da energia do fluxo da
mon{\c{c}}{\~a}o. O efeito dos aeross{\'o}is causou tamb{\'e}m
a intensifica{\c{c}}{\~a}o do Jato de Leste Africano e o
enfraquecimento do Jato de Leste Tropical. Este efeito sobre os
jatos {\'e} tido como uma das causas da redu{\c{c}}{\~a}o da
precipita{\c{c}}{\~a}o na {\'A}frica Ocidental. Tamb{\'e}m, o
impacto dos aeross{\'o}is sobre estes sistemas e no padr{\~a}o
da precipita{\c{c}}{\~a}o foi maior na simula{\c{c}}{\~a}o com
a inclus{\~a}o dos aeross{\'o}is antropog{\^e}nico. Em geral, a
intera{\c{c}}{\~a}o dos aeross{\'o}is com o balan{\c{c}}o
radiativo conseguiu interferir na varia{\c{c}}{\~a}o sazonal e
interanual da circula{\c{c}}{\~a}o oeste africana, A
concord{\^a}ncia destes resultados com os obtidos com modelo de
circula{\c{c}}{\~a}o geral aumenta a confiabilidade dos mesmos.
ABSTRACT: This study aims to enhance the knowledge about the
influence of the aerosol radiative forcing on the complex
interaction between the coupled system of earth, atmosphere and
ocean, which results in formation of the African monsoon. The West
African rainfall depends strongly on the activation of the monsoon
circulation. This fact determines the importance of this system in
the agricultural activity, which is highly dependent on climate,
and consequently in the economy of the region that is based on
agriculture. In this study it is used the regional climate model
(RegCM3) coupled with dust and anthropogenic aerosol module. The
dust and anthropogenic effects on the monsoon circulation are
evaluated through the comparison between the experiments with and
without aerosols feedback in the radiation budget. The model is
integrated for June, July, August and September for a dry year
(1983); normal (1996) and wet year (1978). In these years, which
are selected within a 1970-2000 series, it is not observed the
ENSO occurrence. The results show the reduction of the West
African rainfall under effects of cooling induced by dust in the
Sahara and anthropogenic aerosols. This cooling reduces the
meridional gradient of the moist static energy, which causes the
weakening of the energy of the monsoon flux. This effect also
causes a strengthening of the African easterly jet and weakening
of the tropical easterly jet. This effect contributes for a
reduction of the West African rainfall. Also, the impact of
aerosols on these systems and the precipitation was greater in the
simulation with anthropogenic aerosols. In general, the
interaction of aerosols with radiation budget was able to
influence the seasonal and interanual variation of the West
African circulation. The agreement between of these results and
those from general circulation model increases their
reliability.",
committee = "Pezzi, Luciano Ponzi (presidente) and Franchito, S{\'e}rgio
Henrique (orientador) and Roa, Vadlamudi Brahmananda and Yamazaki,
Yoshihiro",
copyholder = "SID/SCD",
englishtitle = "Aerosols impacts on dynamic of the West African monsoon: direct
effects",
language = "pt",
pages = "126",
ibi = "8JMKD3MGP8W/35EMP6S",
url = "http://urlib.net/ibi/8JMKD3MGP8W/35EMP6S",
targetfile = "publicacao.pdf",
urlaccessdate = "03 maio 2024"
}