Tracking an Oil Tanker Collision and Spilled Oils in the East China Sea Using Multisensor Day and Night Satellite Imagery

Satellite remote sensing is well known to play a critical role in monitoring marine accidents such as oil spills, yet the recent SANCHI oil tanker collision event in January 2018 in the East China Sea indicates that traditional techniques using synthetic aperture radar or daytime optical imagery could not provide timely and adequate coverage. In this study, we show the unprecedented value of Visible Infrared Imaging Radiometer Suite (VIIRS) Nightfire product and Day/Night Band data in tracking the oil tanker's drifting pathway and locations when all other means are not as effective for the same purpose. Such pathway and locations can also be reproduced with a numerical model, with root-mean-square error of < 15 km. While high-resolution optical imagery after 4 days of the tanker's sinking reveals much larger oil spill area (>350 km(2)) than previous reports, the impact of the spilled condensate oil on the marine environment requires further research. Plain Language Summary The Iranian oil tanker SANCHI collided with a grain freighter on 6 January 2018 in the East China Sea, causing major fires and oil spills. For event response, nighttime data collected by the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite instrument show unprecedented value in monitoring the fires and tracking the >350 km drifting pathway of the SANCHI tanker. A numerical model to combine surface currents and wind can also simulate the tanker's locations until it sank on 14 January. Satellite remote sensing during daytime shows smokes and spilled oil on the ocean surface, some of which appears to be oil emulsion. A combination of all available remote sensing and modeling techniques can provide effective means to monitor marine accidents and oil spills to assist event response.