8/6/2019 C2 Poster Oil5 Oceans From Space Perkovic OK-A4

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Space Based Surveillance:

Advances Toward Polluter Identification

M. Perkovica*, H. Greidanusb, G. Ferrarob, O. Mllenhoffc, S. Petelina, R. Harscha

a* University of Ljubljana, Faculty of Maritime Studies and Transport, Slovenia marko.perkovic@fpp.uni-lj.si

b Joint Research Centre, European Commission, Ispra

c BMT Argoss, Milano, ItalyABSTRACT:

Marine oil spills pose a risk for European coastlines (ecological, socio-economic damage, etc). For this reason European coastal states have established surveillance systems to monitor the state of the

seas, to deter illicit polluters and to support combating activities. The spaceborne SAR surveillance system provides added value to the problem of monitoring marine pollution from ship discharges.

The paper focuses on the identification of illicit oil polluters through the integration of a vessel traffic service system together with a satellite surveillance system and the subsequent superimposition of

meteorological and oceanographic conditions within oil spill application.

INTRODUCTION

Illicit oil discharging, a common practice, represents the main source ofmarine pollution from ships, amplifying the demand for efficient detection

and mapping of oil spills (Ferraro et al., 2007). Key instruments for

detecting and monitoring spills at sea are Synthetic Aperture Radar (SAR)

systems, which are able to detect spills on the sea surface indirectly given

the damping of Bragg waves. The oil film dampens these waves, the

primary backscatter agents of the incident radar beam, appearing as darkpatches on the SAR image. Bragg waves are induced by surface winds but

are also modulated by other ocean surface features.

Diverse kinds of pollution can cause slicks detectable by SAR (e.g.,

vegetable oil, river runoff, drilling fluid from an oil rig, etc.) and the SAR

sensor is currently not capable of distinguishing between the different

pollutants. In practice it is very difficult to distinguish surface films from

each other by merely analyzing the radar backscattering data (Mllenhoff et

al., 2008). Knowledge of environmental conditions as well as contextual

information about slick position relative to surrounding objects (ships,

maritime routes, rigs, wrecks and undersea pipelines) is in many cases

essential for determining the probability of oil spills extant on SAR imagery

(Ferraro et al., 2010). Further, for successful backtracking of illicit

polluters, when slicks are already weathered highly accurate metocean data

are necessary to move the slicks from their detected locations towards the

origins of the spills and to identify the polluters.

To reduce or even eliminate illicit pollution at sea, in 2007 EMSA launched

a European operational system for marine oil slick surveillance allowing

detection of possible oil spills in all European waters. The system is

CleanSeaNet (CSN), designed to support improvements such as greaterconsistency, efficiency and effectiveness of pollution monitoring efforts of

Member States. Since CleanSeaNets inception more than 2000 yearly SAR

images have indicated almost 3000 slicks ( per year). Some intensive

validation was performed, confirming detections as oil. In a few cases illicit

discharging was detected just as ships or other objects were pumping out

oily water. But as yet there have been no cases in which a polluter was

unassailably identified from analysis of weathered slicks.

Now EMSA will launch a new web based application allowing operators to

run spill advection models that will move detected slicks backwards against

currents and winds towards potential polluters EMSA (2008).

MATERIALS AND METHODS

An ideal case - a freshly released slick or a ship attached to the slick - israre. Usually the image shows a slick already weathered, and no ships or too

many of them in the vicinity. If the slick is outside AIS range, polluter

detection is virtually impossible. For precise backtracking, accuratemetocean data and a view of the overall shipping situation in the area is

required. Extensive local data must be available - contextual particulars of

bathymetry, wrecks, piping and drilling activity, natural seeps, shore

industry, metocean phenomena, fishing traffic, and for truly accurate

backtracking validation of metocean data is essential; shipping data must be

analyzed clearly and matched with port authorities log books (Mllenhoff et

al., 2008, Ferraro et al., 2010). Further complications are unknowns like the

type of oil or mixture that was discharged, quantities and initial locations.

Through this fog we must decide how long to backtrack the slick and roll

back AIS archives. Oil type is an important factor, for the way an oil slick

breaks up and dissipates depends largely on how persistent the oil is. Light

products, non-persistent oils (e.g., kerosene), tend to evaporate and dissipate

quickly and naturally and rarely need cleaning-up. Persistent oils, such as

many crude oils, act more slowly and usually require clean-up. Physical

properties such as density, viscosity and pour point all affect oil behavior.

Dissipation also depends on weather conditions and whether the oil stays at

sea or is washed ashore. Figure 1 illustrates the complete procedure for

backtracking and identification.

CONCLUSION

This case clearly illustrates the impintegrating several systems; yet anoth

integration is necessary - between sci

lawyers. In this case there was no poss

prosecution as there was no sampling don

REFERENCES

1. Ferraro, G., Bernardini, A., David, M., Meyer-Roux, S., Muellen

Perkovic, M., Tarchi, D., Topouzelis, K., (2007). Towards an ope

of space imagery for oil pollution monitoring in the Mediterranean

Marine Pollution Bulletin. Volume 54, no. 4, pp. 403-422.

2. Mllenhoff, O., Bulgarelli, B., Ferraro, G., Perkovic, M. Topouzel

Sammarini, V. (2008). Geospatial modelling of metocean and en v

ancillary data for the oil spill probability assessment in SAR imag

Proceedings of the SPIE, Volume 7110, pp. 71100R-71100R-10.

3. Ferraro, G. Baschek, B., de Montpellier, G., Njoten, O. Perkovic, M

Vespe, M. (2010). On the SAR derived alert in the detection of oi

according to the analysis of the EGEMP. Marine Poll. Bull., vol.

pp. 92-102.

4. EMSA (2008). EMSAs view on the further development of oil sp

non paper. November 2008, Lisbon, http://cleanseanet.emsa.europ

Figure 1. SAR processing and backtracking methodology

University of Ljubljana

Faculty of Maritime Studies and Transport

Processing

ValidationMetocean data &

Hind Cast Oil Spillmodeling and

polluter backtracking

Early warnings, Confirmation& Response

Metocean&

Oil Spillforecast modeling

Advanced responsesupport

ShippingdataRADARAISVMSLRITReportsSATLog Book ...

GIS dataTSSPortsTerminalsPlatformsWrecksNatural seeps

Bathymetry ...

Metocean dataWindWavesCurrentsTidesSSTChlorophyll

Polluter identification

P R O S E C U T I O N

Collecting evidence

Deterrenteffect

RESULTS EXPLICATED BY CASE STUDY

During 2005/2006 the Faculty of Maritime Studies, alongwith EC JRC and other partners under the lead of REMPEC,

was part of the AESOP (Aerial and Satellite surveillance of

Operational Pollution in the Adriatic Sea) project, meant for

validating the prospect of satellite radar control over illegal oil

spills. The specific goal was identifying ships responsible for oil

spills (Ferraro et al., 2007). Following is one resultant case of

pollution source identification by integration of satellite images,

data on weather history conditions, AIS traffic archives and

mathematic tools (PISCES) for hindcast oil spill simulations.

Figure 2 acquired by ERS2 ( ESA) on 26th June 2006 at

09:42 GMT, distinctly shows a dark feature, likely a partially

weathered oil slick. To begin a search for the polluter, retrieving

the AIS history database was necessary (The identification

distance was almost 300 miles from the AIS antenna!). Given the

dense traffic the direction of the ship responsible had to be

determined. After geo-coordinating the SAR image andoverlaying it on electronic charts it appeared the discharge began

immediately after a north-bound vessel passed the traffic

separation scheme; yet inspection of the shape indicated that the

slick was much more weathered on the north side - that the ship

was southbound. The next step was overlaying the currents field

and wind conditions - evidently surface currents (more

determinate than wind direction) moved almost perpendicular to

the line of the slick. Even weak currents can rapidly disturb the

slick shape, pushing it in a particular direction - north-east in

this case, supporting the conclusion that the polluter was

southbound. Further Metocean validation was performed,

analyzing vessel drift using the average difference of ships

headings and courses through a sailing leg. Next, oil spill

simulation in hindcast mode and retrieval of shipping archive

data acquired by theAIS-based VTS system was required.

Figure 2 shows the position of ships at the time the SAR image

was acquired: 1032 LT.

The suspect polluter, a cargo ship, U* Tr

already at the end of the TSS. Sailing

course indicated that the illicit discha

around 0725 LT more than three hours

SAR image was available. Because the

intensely disturbed in the middle towar

direction, it was assumed that another sh

the slick, which was confirmed by AIS

e.g., a fast passenger ship crossed at 2

disturbance provided further confirmatio

dark formation was indeed a slick

Clearly in the near future EU jurists must work with oil sp

to coordinate a system whereby space technology ca

prosecution. At the same time space technologists mu

develop finer remote sensor capability. Most importan

however, is that this case demonstrates that important ad

being made toward eliminating operational pollution.

Figure 2. Hindcast simulation and polluter identification

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