@PhDThesis{BritoNeto:2023:EsSoVa,
author = "Brito Neto, Francisco Agustinho de",
title = "Estudo sobre a variabilidade da {\'a}gua intermedi{\'a}ria
ant{\'a}rtica no Oceano Austral utilizando o modelo BESM-OA",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2023",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2023-03-20",
keywords = "onda circumpolar ant{\'a}rtica, mar de Weddell,
rejei{\c{c}}{\~a}o de sal, salinidade, antarctic circumpolar
wave, Weddell sea, brine rejection, salinity.",
abstract = "O gelo marinho no Oceano Austral apresenta
caracter{\'{\i}}sticas particulares em compara{\c{c}}{\~a}o
com o {\'A}rtico. Em um cen{\'a}rio de aquecimento global,
{\'e} esperado que o comportamento do gelo marinho da
Ant{\'a}rtica siga o padr{\~a}o de tend{\^e}ncias negativas
observado no {\'A}rtico. Contudo, nota-se que, em m{\'e}dia, o
gelo marinho no Oceano Austral apresenta tend{\^e}ncias
positivas. Esse padr{\~a}o diverge da maioria dos modelos
clim{\'a}ticos utilizados nos relat{\'o}rios do Painel
Intergovernamental sobre Mudan{\c{c}}as Clim{\'a}ticas. Esse
fato indica que os modelos utilizados para fazer
proje{\c{c}}{\~o}es clim{\'a}ticas s{\~a}o limitados na
representa{\c{c}}{\~a}o dos processos que modulam o clima do
sistema terrestre. Essa limita{\c{c}}{\~a}o pode decorrer tanto
de solu{\c{c}}{\~o}es matem{\'a}ticas inadequadas quanto de
desconhecimento f{\'{\i}}sico de alguns processos determinantes
nas regi{\~o}es polares. Portanto, o objetivo geral deste estudo
{\'e} compreender quais mecanismos s{\~a}o respons{\'a}veis
pela variabilidade da {\'A}gua Intermedi{\'a}ria Ant{\'a}rtica
(AAIW) por meio da intera{\c{c}}{\~a}o entre a extens{\~a}o do
gelo marinho e a Onda Circumpolar Ant{\'a}rtica (OCA) no modelo
acoplado BESM-OA vers{\~a}o 2.5 (Brazilian Earth System Model
coupled Ocean-Atmosphere). A {\'a}rea de estudo foi o Oceano
Austral (OA), com {\^e}nfase no Mar de Weddell (MW) e no Oceano
Atl{\^a}ntico. Al{\'e}m disso, avaliou-se a
representa{\c{c}}{\~a}o das vari{\'a}veis que constituem a AAIW
e a Onda Circumpolar Ant{\'a}rtica, como press{\~a}o ao
n{\'{\i}}vel m{\'e}dio do mar, temperatura potencial,
salinidade pr{\'a}tica do oceano e gelo marinho, no modelo
BESM-OA 2.5. Utilizou-se o experimento hist{\'o}rico do CMIP5
para avaliar o per{\'{\i}}odo de 1982 a 2005. Al{\'e}m disso,
analisou-se como outros modelos do CMIP representam a
intera{\c{c}}{\~a}o da Onda Circumpolar Ant{\'a}rtica com o
gelo marinho. Para identificar a OCA, utilizou-se o m{\'e}todo de
decomposi{\c{c}}{\~a}o dos harm{\^o}nicos de Fourier com o
objetivo de isolar o sinal de propaga{\c{c}}{\~a}o para leste da
OCA. Os resultados mostraram que o modelo BESM-OA 2.5 superestima
a a quantidade de gelo marinho sobre o Oceano Austral no
per{\'{\i}}odo de m{\'a}xima extens{\~a}o de gelo (Agosto -
Setembro - Outubro), diferentemente do conjunto de modelos MIROC5
e MIROC6, que subestima em todos os per{\'{\i}}odos do ano a
quantidade de gelo marinho. Essa representa{\c{c}}{\~a}o gera
uma menor quantidade de precipita{\c{c}}{\~a}o de sal nas
camadas superiores do que {\'e} observado em torno do Oceano
Austral, por outro lado, o BESM-OA possui maior quantidade de sal
injetado. Essa caracter{\'{\i}}stica favorece para que os
modelos que subestima a forma{\c{c}}{\~a}o de gelo marinho,
apresente defici{\^e}ncias na representa{\c{c}}{\~a}o das
caracter{\'{\i}}sticas da {\'A}gua Intermedi{\'a}ria
Ant{\'a}rtica. Al{\'e}m disso, o modelo BESM mostrou o
acoplamento oceano - gelo marinho - atmosfera da Onda Circumpolar
Ant{\'a}rtica, controlando a variabilidade de baixa
frequ{\^e}ncia da concentra{\c{c}}{\~a}o de sal na regi{\~a}o
de forma{\c{c}}{\~a}o da AAIW, diferentemente do MIROC5 que
devido n{\~a}o mostra um acomplamento claro, n{\~a}o tendo tanto
impacto na modula{\c{c}}{\~a}o da precipita{\c{c}}{\~a}o de
sal. ABSTRACT: Sea ice in the Southern Ocean has unique
characteristics compared to the Arctic. In a global warming
scenario, it is expected that Antarctic sea ice behavior will
follow the negative trend observed in the Arctic. However, on
average, Southern Ocean sea ice shows positive trends. This
pattern diverges from most climate models used in the
Intergovernmental Panel on Climate Change reports. This fact
indicates that the models used to make climate projections are
limited in representing the processes that modulate the Earth
system climate. This limitation may result from inadequate
mathematical solutions or a lack of physical knowledge of some
processes that are determinant in polar regions. Therefore, the
general objective of this study is to understand which mechanisms
are responsible for the variability of Antarctic Intermediate
Water (AAIW) through the interaction between sea ice extent and
the Antarctic Circumpolar Wave (ACW) in the coupled model BESM-OA
version 2.5 (Brazilian Earth System Model coupled
Ocean-Atmosphere). The study area was the Southern Ocean, with an
emphasis on the Weddell Sea and the Atlantic Ocean. In addition,
the representation of variables that constitute AAIW and the
Antarctic Circumpolar Wave, such as sea level pressure, potential
temperature, ocean practical salinity, and sea ice, was evaluated
in the BESM-OA 2.5 model. The CMIP5 historical experiment was used
to evaluate the period from 1982 to 2005. Furthermore, it was
analyzed how other CMIP models represent the interaction between
the Antarctic Circumpolar Wave and sea ice. The Fourier harmonic
decomposition method was used to identify the ACW and isolate the
eastward propagation signal. The results showed that the BESM-OA
2.5 model overestimates the amount of sea ice over the Southern
Ocean during the maximum sea ice extent period (August-
September-October), unlike the MIROC5 and MIROC6 models, which
underestimate sea ice amount throughout the year. This
representation results in a lower amount of salt precipitation in
the upper layers than observed around the Southern Ocean, whereas
the BESM-OA has a greater amount of injected salt. This
characteristic favors models that underestimate sea ice formation
and present deficiencies in representing the characteristics of
AAIW. In addition, the BESM model showed the ocean-sea
ice-atmosphere coupling of the Antarctic Circumpolar Wave,
controlling the low-frequency variability of salt concentration in
the AAIW formation region, unlike MIROC5, which does not show a
clear coupling and therefore has less impact on salt precipitation
modulation.",
committee = "Giarolla, Emanuel (presidente) and Nobre, Paulo (orientador) and
Mendes, David and Capistrano, Vinicius Buscioli and Cintra,
M{\'a}rcio Machado",
englishtitle = "Study on the variability of antarctic intermediate water in the
southern ocean using the BESM-OA model",
language = "pt",
pages = "81",
ibi = "8JMKD3MGP3W34T/48N8DHL",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/48N8DHL",
targetfile = "publicacao.pdf",
urlaccessdate = "20 maio 2024"
}