Oil slicks in the Gulf of Guinea – 10 years of Envisat ASAR observations
Abstract. Gulf of Guinea is a very active area regarding maritime traffic as well as oil and gas exploitation (platforms). As a result of some actors of both sectors that fail to comply with environmental standards, the region is subject to a large number of oil pollutions. This study aims to detect oil slicks spilled in the Gulf of Guinea and analyse their spatial distribution using Synthetic Aperture Radar (SAR) images. If previous works have already locally mapped oil slicks in this area, this study is the first one to achieve a global statistical analysis based on a very high number of radar images covering 17 Exclusive Economic Zones of the Gulf of Guinea. To carry out the present study, a database of 3,644 SAR images, collected between 2002 and 2012 by the Advanced SAR (ASAR) sensor onboard the European Spatial Agency (ESA) Envisat mission has been used. This database allowed the identification of 18,063 oil slicks. These "Oil slicks" herein detected regroup: "oil spills" – of anthropogenic origin- and "oil seeps" – of natural origin (natural oil reservoir leaks).