An assessment of marine oil pollution in Indonesia based on SAR imagery

We analyzed more than 5000 synthetic aperture radar (SAR) images from ERS 1/2, ENVISAT, ALOS-1, and Sentinel-1A with respect to marine oil pollution in two regions of interest (ROIs) in Indonesian waters. Both normalized spill number and normalized mean polluted area indicate that the marine oil pollution in the ROIs generally is of different origin: while ship traffic appears to be the main source in the Java Sea, oil production industry causes highest pollution rates in the Strait of Makassar. Largest oil spill numbers in the Java Sea were found during the transition from north-west to south-east monsoon, and vice versa, when the overall wind and current patterns change, thereby making oil pollution detection with SAR easier. We further demonstrate that high-resolution numerical forward and backward tracer experiments, in combination with (visual) SAR image analyses help in better understanding the observed seasonality.