@MastersThesis{Freitas:2012:DeFeOc,
author = "Freitas, Lucas Barbedo de",
title = "Detec{\c{c}}{\~a}o de fei{\c{c}}{\~o}es oceanogr{\'a}ficas,
filmes minerais e biog{\^e}nicos via imagens MODIS na
condi{\c{c}}{\~a}o de sunglint",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2012",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2012-05-23",
keywords = "sunglint, cor do oceano, fei{\c{c}}{\~o}es oceanogr{\'a}ficas,
biofilmes, filmes minerais, sunglint, ocean color, oceanography
features, biofilms, mineral films.",
abstract = "O avan{\c{c}}o da fronteira mar{\'{\i}}tima devido {\`a}
extra{\c{c}}{\~a}o de petr{\'o}leo em {\'a}guas profundas e a
consequ{\^e}ncia de vazamentos que possam atingir ambientes
sens{\'{\i}}veis e de dif{\'{\i}}cil regenera{\c{c}}{\~a}o
levantam {\`a} necessidade de novas tecnologias de monitoramento.
Imagens de radar de abertura sint{\'e}tica da superf{\'{\i}}cie
do oceano s{\~a}o largamente utilizadas para detectar manchas de
petr{\'o}leo e tamb{\'e}m biofilmes. Embora a
aquisi{\c{c}}{\~a}o SAR ocorra em qualquer condi{\c{c}}{\~a}o
atmosf{\'e}rica e de ilumina{\c{c}}{\~a}o solar, a boa
detec{\c{c}}{\~a}o destes surfactantes {\'e} regrada pelo vento
na superf{\'{\i}}cie marinha e sua influ{\^e}ncia na
forma{\c{c}}{\~a}o de ondas de \textit{Bragg}. A sinergia de
produtos meteo-oceanogr{\'a}ficos {\'e} essencial para auxiliar
a distin{\c{c}}{\~a}o de surfactantes, entre biog{\^e}nico e de
petr{\'o}leo; assim como de outras fei{\c{c}}{\~o}es de
din{\^a}mica oceanogr{\'a}fica como v{\'o}rtices, meandros,
ondas internas e bordas de correntes; eventos atmosf{\'e}ricos
como ventos fracos, sombra de vento devido a relevo costeiro,
estabilidade na camada limite ar-mar e precipita{\c{c}}{\~a}o.
Os sensores {\'o}pticos de cor do oceano, dentro de especificas
condi{\c{c}}{\~o}es geom{\'e}tricas de aquisi{\c{c}}{\~a}o e
vento resultam em imagens com reflex{\~a}o especular bidirecional
na superf{\'{\i}}cie do oceano, o \textit{sunglint}, ao qual
possui informa{\c{c}}{\~a}o a respeito da rugosidade da
superf{\'{\i}}cie marinha. O efeito dos surfactantes imp{\~o}e
inel{\'a}sticidade na superf{\'{\i}}cie marinha, alterando o
padr{\~a}o de rugosidade, o que possibilita detectar filmes
minerais ou biog{\^e}nicos. Esta detec{\c{c}}{\~a}o via
\textit{sunglint} ocorre mesmo em condi{\c{c}}{\~o}es de baixo
vento (< 2m/s), dificilmente eficazes no SAR. As
condi{\c{c}}{\~o}es de contraste entre um filme surfactante e
{\'a}guas limpas circundantes s{\~a}o modeladas e fornecem
informa{\c{c}}{\~a}o qualitativa (contraste negativo ou
positivo) e quantitativa sobre o contraste causado pela mancha de
{\'o}leo, diminuindo ambiguidades causadas por
fei{\c{c}}{\~o}es oceanogr{\'a}ficas e atmosf{\'e}ricas. Um
caso de filme biog{\^e}nico resultado de Bloom da
cianobact{\'e}ria \textit{Trichodesmium, em janeiro de 2003} e
um vazamento de petr{\'o}leo em novembro de 2011, ambos na costa
sudeste do Brasil, s{\~a}o analisados com auxilio de grande
diversidade de dados ambientais e demonstra o quanto imagens de
\textit{sunglint} podem ser importantes na sinergia de sensores
remotos para monitorar surfactantes. O \textit{sunglint} por ser
sens{\'{\i}}vel a varia{\c{c}}{\~o}es da rugosidade de
superf{\'{\i}}cie permite a observa{\c{c}}{\~a}o de
fei{\c{c}}{\~o}es de mesoescala, entre elas detalhadas neste
estudo meandros, v{\'o}rtices, borda oeste da Corrente do Brasil,
ondas internas, modula{\c{c}}{\~a}o do vento pelo relevo e
plumas de rios na regi{\~a}o sudeste do Brasil. ABSTRACT: When
interpreting satellite oceanic scenes the synergy of
meteo-oceanographic products is essential to assist a better
separation of surfactants into oil or biofilms. The same is true
for the classification of other features associated to the
dynamics of the ocean such as current meanders and fronts,
internal waves, eddies and to atmospheric events such as low wind
zones, wind shadows due coastal or island topography and lower
atmosphere boundary layer processes. Synthetic Aperture Radar
(SAR) images of the ocean surface have been used with success in
detecting oil spills and biofilms. The detection of these
surfactants in SAR images is possible due to the damping effect of
surfactants on short wavelength roughness (Bragg capillary waves)
produced by the wind friction. The main goal of this study was to
evaluate the usefulness of ocean color images under sunglint
condition for complementing estimates of ocean features extracted
from SAR images. Under specific geometric configurations of Sunīs
illumination, sensor viewing and wind intensity and direction, the
bi-directional specular reflection of ocean surface will contain
the sun glint, a region of high reflectance of solar rays. The
size and intensity of the glint depends on the distribution of sea
surface slopes (short scale roughness), a function of the wind.
The wind induced roughness has an anomalous behavior under the
action of surfactant films. These anomalous roughness regions will
affect the normal glint reflection, allowing the detection of
surfactants in glint images even in conditions of low wind (<
2m/s), a situation that makes SAR images almost useless for oil
detection. In this work the sunglint contrast between a surfactant
film and clean water is modeled using Cox and Munk (1954) sea
surface slope PDF. We derive a contrast index and show that it can
be used qualitatively (negative or positive) and quantitatively to
help separate 15 the observed surfactant signatures from
ambiguities caused by some atmospheric and oceanographic features.
Two case studies are presented for the southeast coast of Brazil
to demonstrate how sunglint images can be very useful as synergy
tool in the remote sensing of surfactants in the ocean. One case
study is of biofilms produced by cyanobacteria
\textit{Trichodesmium} Bloom in January 2002 and another refers
to an oil spill in November 2011. We also present some examples of
sunglint images used for the detection and observation of internal
waves, ocean mesoscale features, river plumes, nearshore winds,
and coastal process.",
committee = "Gherardi, Douglas Francisco Marcolino (presidente) and Kampel,
Milton (orientador) and Lorenzzetti, Jo{\~a}o Ant{\^o}nio
(orientador) and Bentz, Cristina Maria",
copyholder = "SID/SCD",
englishtitle = "Ocean features, biogenic and natural films detection by MODIS
under sunglint",
language = "pt",
pages = "131",
ibi = "8JMKD3MGP7W/3C8B9H2",
url = "http://urlib.net/ibi/8JMKD3MGP7W/3C8B9H2",
targetfile = "publicacao.pdf",
urlaccessdate = "12 maio 2024"
}