This document discusses remote sensing technologies for monitoring oil spills in the Mediterranean Sea. It summarizes that hyperspectral and multispectral imagery can be used to detect oil spills, estimate their thickness and type. Laboratory and in situ measurements are needed to create an extensive spectral library to accurately analyze oil spills remotely. The document also presents a case study where a natural oil seep was discovered in the Mediterranean using historical Landsat images and RapidEye satellite data.

1. SST-234096
New strategies and technologies for the
safety of navigation in the Mediterranean
sea
Remote Sensing
Surveillance Technologies
Vassilia Karathanassi, Pol
Kolokoussis
karathan@survey.ntua.gr, pol@survey.ntua.gr
Laboratory of Remote Sensing
National Technical University of Athens
21 November 2012
Centro Culturale De Laugier, Portoferraio, Isola d’Elba (ITALY)

2. Optical Remote Sensing
• Spectroscopy
– Laboratory measurements
– In situ measurements
• Hyperspectral remote sensing
• Multispectral remote sensing
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3. Spectroscopy
Laboratory
measurements
Is it possible to detect the
oil type?
Yes. Reflectance is rising
from light to heavy oils.
RWATER < RKEROSENE < RHEATING OIL <
RCRUDE OIL < RHEAVY FUEL < RMARINE
FUEL OIL.
Ratios between R of each oil type
and R of sea water (344.51 nm)
OIL TYPE
RATIOS
DAYS
KEROSENE
1.53-1.54
1,2
HEATING OIL
1.64-1.76
1,2
Laboratory experiments
CRUDE OIL
1.86-1.89
1,2,3
included 13 oil types
SRFO
2.08-2.09
1,2,3
BUNKER 3
2.30-2.51
1,2
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4. Spectroscopy
Laboratory
measurements
Is it possible to detect the
thickness of the oil?
Yes. The thicker the oil spill,
the higher its reflectance.
Best-fit functions for each oil
type
8 different thicknesses
ranging from 1μm to
2mm
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5. Spectroscopy
From laboratory to
in situ
measurements
Does the oil spill present the
same spectral signature in
the marine environment?
No. Thin oil-spills and sea
water present sea bottom
contributions.
Denser oils like the Arabian
present minor sea bottom
contributions even for thin
layers of oil-spills (150μm).
Example of spectral
signatures of blend oil-spill
WE NEED AN EXTENDED OIL
in marine environment
SPECTRAL LIBRARY IN MARINE
ENVIRONMENT
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6. Hyperspectral Remote sensing
Hyperspectra
l Sensor
In hyperspectral imagery each pixel contains a unique, continuous
spectrum which is used for the identification of materials by their
reflectance.
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7. Airborne Hyperspectral images
CASI-550 airborne hyperspectral imagery has been acquired
for the ARGOMARINE project
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8. Hyperspectral Remote sensing
Oil spill detection
Can we detect oil spills by
processing a hyperspectral
image?
- Yes. Even very thin oil-spills
can be detected.
The only constraint is the
presence of clouds. They
should be excluded from the
image.
Do airborne and in situ
spectral measurements
coincide?
Results of the hyperspectral oil-spill - Almost Yes.
detection methodology for the Laganas
bay, Zakynthos.
The small and very thin oil spill was caused
by a natural oil outflow.
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9. Hyperspectral Remote sensing
Methodology for oil spill detection
Pre-processing of the hyperspectral Can we detect the type of
image (radiometric, atmospheric correction and
georeference)
an
oil spill by processing a
Signal subspace estimation
(The Intra-StD method has been
hyperspectral imagery?
developed within ARGOMARINE)
Yes. If there is an extended
Dimensionality Spectral Library for the
reduction
marine environment under
real biophysical conditions.
Endmember extraction
(The Improved-SEE method has been
developed within ARGOMARINE)
SAM classification or Abundance fraction
algorithm for thickness estimation
(The NBM method has been developed within
ARGOMARINE)
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10. Hyperspectral Remote sensing
Oil spill thickness estimation
Can we estimate the thickness of
an oil spill by processing a
hyperspectral imagery?
Yes. Relative thickness for the oil-
spill can be estimated.
This could lead to absolute
thickness estimation in case that in
situ measurements in the area with
the greatest oil concentration is
performed.
Can we avoid in situ
Map of oil-spill relative
measurements?
thickness
Yes. If there is an extended Spectral
Library for the marine environment
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biophysical conditions.
under real

11. Hyperspectral Remote Sensing
How to build an extended Spectral
Library
for the marine environment
The Integrated ARGOMARINE methodology
Is it tested?
Only on MODIS
and ASTER
imagery with
Satisfactory
results.
A next research
program is
needed.
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12. Multispectral Remote sensing
for oil spill detection
Can we detect an oil spill by
processing a very high spatial
resolution multispectral imagery?
Yes.
Can we detect the oil spill type?
No.
Can we detect the oil spill
thickness?
Object based oil-spill detection on an No.
IKONOS image of Beirut, Lebanon (August
5th 2006)
Is the methodology also
applicable on high resolution
multispectral images (i.e. Landsat
TM)?
Yes (providing average to good
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detection results).

13. Multispectral Remote sensing
Methodology for oil spill detection
Multispectral image
geocoding.
Application of ATCOR3 atmospheric
corrections and conversion of the
raw image digital numbers to
surface reflectance values.
Masking of the non-sea
areas, i.e. land and clouds.
Image multiresolution
segmentation in two
levels
(fine and broad).
Oil-spill detection using
object based classification
rules
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14. Remote Sensing potentials for
Natural oil outflow detection
Can we detect an unknown oil
natural outflow using remote
sensing imagery?
Yes. Within the ARGOMARINE
project by processing very high
resolution (RapidEye) as well as
historical high resolution
(Landsat TM) multispectral
imagery, a large unknown
systematic natural oil outflow
near the island of Zakynthos has
been discovered. The oil-spill
Multitemporal color composite of three RapidEye
occurrence seems to be images of Zakynthos: July 13th 2009 (Blue), July
systematic over a long period of 15th 2009 (Green), and July 16th 2011 (Red).
time (it appears on many Landsat The unusual oil-spill occurrences near
Zakynthos start from a specific point at the open
images from 1986 till 2012) and sea, 6 km south of the area of Keri.
was verified by spot test from a
NMPZ boat.
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15. Thank you for your attention
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