Perkovic, Marko; Petelin, Stojan; Harsch, Rick
(Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie,
2010)
The efforts to maintain the relatively safe status of maritime transport are required, but unfortunately these efforts necessarily go beyond technological improvements to measures necessitated by intentional operational polluters. Science in this aspect is relegated to a defensive position, its direction dictated by environmental crime. The old practices of dumping ship-generated waste and pumping out cargo residues apparently will continue until a mean of identifying perpetrators is established and publicized. We hope that satellite technology can play an important complementary and supporting role in detecting and deterring such pollution. When an early-warning message can be delivered to responsible authorities (mainly coast guards) in real time, satellites can effectively support the possibility of identifying the polluting ship and thus open the way to prosecution of the offenders. This paper is about advances in polluter identification methodology beginning with the analysis of SAR images. Because cases in which a freshly released slick is detected are rare, an acquired image usually depicts a slick that is already weathered, with a currents-and-wind-distorted slick footprint and either no ships or too many ships in the vicinity. If AIS (Automatic Identification System) information is available or can be retrieved through an archive, in most cases the operator is still faces the problem that many ships passed the designated area, or that the slick is outside AIS range, effectively preventing any possibility of identification. Another problem related to polluter tracking is the availability of metocean ancillary data. Highly accurate wind and currents data are necessary for successful backtracking of the slick towards likely polluters and the origin of the spill. Wind and currents data therefore must be validated for instance, by reading headings from anchored ships or analyzing the differences between integrated courses and headings of ships passing through the area under investigation. Drift caused by external forces for a certain vessel may be further validated through the use of a ship handling simulator