Numerical simulations on the transport and dispersion of 137Cs in the upper ocean due to the Fukushima disaster

Abstract

Following the March 2011 Fukushima disaster, large amounts of water contaminated with radionuclides, including 137cs, were released into the Pacific Ocean. With a half-life of 30.1years, 137Cs has the potential to travel large distances within the ocean. Vertical distributions of Fukushima-derived 137Cs were simulated in the Pacific Ocean from 2011 to 2012. The simulations suggest that the contaminated plume would have been rapidly diluted by the energetic Kuroshio Current and Kuroshio Extension by 2012. But in the subtropical region, to the south of the Kuroshio Extension, the maximum 137 Cs appears at s depth of about 300m. It is southward due to formation/subduction of subtropical mode waters within about 10 months after the accident.ithin the ocean. Vertical distributions of Fukushima-derived 137Cs were simulated in the Pacific Ocean from 2011 to 2012. The simulations suggest that the contaminated plume would have been rapidly diluted by the energetic Kuroshio Current and Kuroshio Extension by 2012. But in the subtropical region, to the south of the Kuroshio Extension, the maximum 137 Cs appears at s depth of about 300m. It is southward due to formation/subduction of subtropical mode waters within about 10 months after the accident.