1. Transport and fate of Fukushima-derived 137Cs and 134Cs in the seawater of the Northwest Pacific in 2015.
- Author
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Wang, Fenfen, Men, Wu, Huang, Jiang, Chen, Zhaohui, and Xu, Lixiao
- Subjects
WATER masses ,MESOSCALE eddies ,SEAWATER ,CHOICE of transportation ,INVENTORIES - Abstract
To understand the influence of the Fukushima accident on the Northwest Pacific, the distributions and transportations of
134 Cs and137 Cs in the seawater in the Northwest Pacific in May and September 2015 were studied. The data showed that the Fukushima-derived134 Cs and137 Cs at some stations can still be distinguished from background level ~ 4 years later. On the whole, the activities of137 Cs and134 Cs in seawater were decreasing from May to Sep 2015. But the increased inventories and the surface activities of137 Cs imply that there has ever been an extra137 Cs from offshore water transported to this study area (from 31° N to 27° N, 145° E to 152.5° E) in May 2015. The average activities of137 Cs in subtropical gyre area in south of KE were the highest and the least were to the east of Luzon Strait in 2015. In vertical direction,137 Cs in subtropical gyre area were mainly distributed at 100 ~ 500 m layer and137 Cs only at 500 m layer in this area showed an increasing trend from May to Sep 2015 which reflects more137 Cs were still penetrating to deeper layer of 500 m from upper water. But they were almost not found below 1000 m layer. It was associated with the subsurface transport of radiocesiums by Northwest Pacific Mode Water (NPMW) and the diffusion of mesoscale eddy. Different distribution characteristics of137 Cs existed between north of KE and south of KE. The low-temperature-low-salinity water mass likely to be the first Oyashio Intrusion was the main factor that resulted in higher137 Cs appearing at the upper 100 m layers in north of KE. [ABSTRACT FROM AUTHOR]- Published
- 2024
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