International Archives of Photogrammetry and Remote Sensing. Vol. XXXH Part 7C2, UNISPACE in. Vienna, 1999
98
ISPR5
VN1SPACE 111 - ISPRS/EARSeL Workshop on
“Remote Sensing for the Detection, Monitoring
and Mitigation of Natural Disasters”
2:30-5:30 pm, 22 July 1999, VIC Room B
Vienna, Austria
MONITORING OIL SPILLS FROM SPACE: STATE OF THE ART AND PERSPECTIVES
Dr. François Cauneau
Centre d’Energétique. Ecole des Mines de Paris
B.P. 207, F-06904 Sophia Antipolis, France
Fax: +33 (0)4 93 95 7535 E-mail: cauneau@cenerg.cma.fr
ABSTRACT
In the context of the constantly increasing pressure of human activities on the environment, oil spilling has been pointed out as one of
the most representative pollution mechanisms. In the past, since attention was often focused on the most spectacular aspects, i.e.
accidental oil pollution, oil spilling has been long associated with tire petroleum industry. Advanced monitoring techniques have
brought evidence that for the most part marine oil pollution is not accidental, but chronic, due in fact to the whole domain of shipping
activity.
During the past ten years improvements in oil spill monitoring techniques using airborne and spacebome remote sensing have
considerably changed this perception, showing to national and international authorities the exact extent of the phenomenon, the variety
of its sources, and the means thus supplied to assess the possible impacts on the global environment.
The first studies to assess the extent of oil spilling activity on the scale of a whole basin were developed for the EC, over the
Mediterranean (see e.g. Wald et al., 1984). Based on the systematic processing of optical data, provided by low resolution radiometers
such as Landsal-MSS, such studies brought into evidence tire order of magnitude of the activity, which revealed to be far beyond the
most pessimistic estimates based on aerial surveys. They confirmed also what liad been suspected for a long time by customs and coast
guards: most oil spills occur off-shore, i.e. in international waters.
The 1990's liave seen the increasing use of spacebome Synthetic Aperture Radars (SARs, such as ERS, Radarsat, JERS, and the
former Almaz systems). Such sensors offer mainly the possibility to acquire day and night images regardless of cloud coverage, and
Space Agencies expected oil spill monitoring to be one of the most important civil applications of the SARs. Thus, SARs have been
extensively used for this purpose, and a strong policy of project funding has been developed, in particular by the EC. From
methodology to the design of end-users' operational tools, large studies such as Clean Seas, Oil Watch or DESIMA have significantly
contributed to define the tools that will be in use for oil spill monitoring in tire near future. Such actions have also resulted in new
knowledge in this domain. Among the results achieved, it has been shown that (1) anthropogenic oil spills at sea may be easily
identified, at least on a statistical basis, firstly since global mapping brings to evidence the correlation between slicks locations and the
main shipping lanes; (2) a conclusion of the previous point is that spilling appears to be less the fact of oil tanker than classic ship
transport; (3) there is a strong need for advanced tools to discriminate natural and anthropogenic slicks, especially in areas where the
natural production of surfactants is significant.
The next steps may now be foreseen in three directions: future SARs will allow multi-scale mapping for global coverage and focused
studies. A first axis of development should be that such capacities will be used, in the context of international co-operation, to
generalise to the global ocean the results already obtained in European seas. A second axis is given with the need to develop tools for
the integration of remote sensing data into decision making systems, such as those developed by UNEP in the CAMPS program for the
Mediterranean. Lastly, the results obtained already show a very good synergy' between airborne and spacebome remote sensing. The
latter is already used by civil authorities for prosecuting illegal spilling, but the diagnostic described in this paper shows that till these
efforts would remain meaningless without the development of proper judicial tools, that will allow the prosecution of any polluter in
international maritime waters.
