Oil Slicks from Natural Hydrocarbon Seeps in the Caspian Sea as Viewed Via Satellite Remote Sensing

This work attempts to expand the understanding of the whole picture of the Caspian Sea surface oil pollution and its sources. We present results based on satellite SAR and VIS data obtained in 2015–2020. The paper focuses on the sea surface's oil slicks caused by natural hydrocarbon seepages at the seabed. We discuss the applicability of satellite remote sensing methods for obtaining spatial and temporal characteristics of these slicks. Our study's results include the precise estimation of seabed seeps' actual location in two Caspian Sea regions via satellite remote sensing data. Another finding is the detection rate of oil showings on the sea surface for various sensor types and seasons. Further, we assess the seasonal and spatial variability of natural oil showings on the sea surface and compare rates of crude oil releases from the seabed to the sea surface in the regions of interest. We present maps of the sea surface oil pollution due to natural hydrocarbons seabed seepages and outline areas of the high risks of sea surface oil pollution.