Monitoring of oil slicks in the Persian Gulf using Sentinel 1 images

Abstract

Sentinel1 data were applied to monitor oil pollution in the Persian Gulf in the vicinity of a Hormuz Strait. Radar images were recorded by sentinel 1 A from January to July 2020. To analyze radar images, two different algorithms were used for oil spill detection and wind field estimation. Based on the result, amplitude VV can be the best band to detect oil spills while intensity VV can be a suitable choice for wind field estimation. Testing many cases, the best threshold shift and minimum cluster size were considered 1.9 dB and 0.08 km respectively for oil spill algorithm compared to 10 km window size for wind field estimation. The outputs revealed that the March was the most polluted month with this contamination clearly found in Qeshm island and the southern part of the Hormuz Strait. We tracked the path of oil slicks when moving Oman coast. The calculation showed that the volume of some slicks can be up to 160 km2. The wind field estimation algorithm indicated that the mean wind speed can be 5 m/s while this value in spring was greater than in winter. Further, some physical oceanography processes play an important role in propagating oil spill in the Persian Gulf such as wind, wave, the frontal system. In the Persian Gulf, the baroclinic instability is as a result of inflow and outflow current in this basin, leading to some meso-scale eddies which have an important role in propagating oil spills. Due to the importance of wave breaking in this region, the entrainment rate from breaking wave was estimated at 9× 10−7 s−1 with weber number and Ohnesorge number 5135 and 6.9 respectively.