Tracing flood induced floating marine debris using a model and the Geostationary Ocean Color Imager (GOCI)

Abstract

On August 31, 2016 the Typhoon Lionrock landed on Primorsky Krai, Russia causing heavy rain fall around the border between the Russia and North Korea. The rain caused flooding along the Tumen River, the border between North Korea and Russia. Several days after the flooding, debris consisted with logs and household garbage were found along the East coast of Korea. The debris, of course, had negative impact on the tourism and coastal eco system. In addition to the debris landed on the East coast of Korea, there must be others drifting toward other areas or floating in the ocean. Logs floating on coastal water could be hazardous to marine traffic, and tracing the fate of the debris from the river is an important task. A Lagrangian particle model utilizing ocean circulation model output is commonly used to trace marine litter. The debris due to the typhoon is episodic and more focused approached is required. In addition, to cope with potential danger posed by large flood debris nearreal time tracking is indispensable. For real time monitoring satellites are very useful. The size of less than a few meters at the most and it is too small to be identified using a satellite whose resolution is usually a few hundred meters or grater. Flooded water, however, could contain a large amount of sediment and could have distinct ocean color. By analyzing data from the Geostationary Ocean Color Imager (GOCI) that provides ocean color images of about 500 m resolution, it was possible to trace the debris from the flooding. The trajectories of the debris from Lagrangian particle tracking modelling and the patterns of anomalous ocean color are comparable along the East Coast Korea. The transport of the debris is due to the North Korea Cold Current that flows southward along the coast of Korea. The Lagrangian particle tracking model suggests that there could be debris in offshore area, but this offshore distribution cannot be confirmed from the GOCI images. This is because in offshore are