Research on Oil Pollution of the Caspian Sea by GIS Systems

Abstract

The Caspian Sea is the largest inland water body on Earth without a direct connection to the world’s oceans, which makes it a unique water reservoir. This fact makes the Caspian Sea particularly vulnerable and subject to human influence, for example, pollution from shipping activities and oil transports by ships. Over the years, oil pollution has been the primary environmental problem of the Caspian Sea. In this paper, we present the results of our satellite survey in 2019 of the whole aquatic area of the Caspian Sea. These results reveal the spatial and temporal distribution of hydrocarbon films of various origins on the sea surface. Our primary attention focused on the main types of petroleum hydrocarbon films polluting the sea surface. The research study shows results from a monitoring campaign in northern and central parts of the Caspian Sea (Kazakhstan sector) for the period from 2005 to 2012 (April–October), based on visual interpretation of radar images from ASAR ENVISAT. Radar data (529 radar images) such as ASAR_WSM_1P and ASAR_IM_1P were obtained from the archives of the European Space Agency. In 529 ASAR ENVISAT images, 160 images were selected, on which 329 oil spills were detected (Aliyev, 2003; Aliyev, 2010; Bayramov et al., 2018; Airbus, 2012; Caspian, 2018). We mapped the petroleum hydrocarbon pollution of the Caspian Sea surface on the base of satellite data. For each type of pollution, specific manifestation features were revealed, regions of regular pollution occurrence were outlined, and polluted areas were estimated. The relative contribution of every kind of pollution to the total oil pollution of the Caspian Sea is assessed on the base of satellite data. A comparison with the previous results of our longterm survey of the Caspian Sea is made (Aliyev, 2003; Bayramov et al., 2018; Lavrova et al., 2019; CIA, 2001).