Vertical profiles of radiocesium ( 134 Cs and 137 Cs) were measured in the western subarctic area of the North Pacific in 2017. The highest concentration of 134 Cs, which was derived from the accident of the Fukushima Dai-ichi Nuclear Power Plant in 2011, was 0.14 Bq m −3 (or 1.19 Bq m −3 after the decay correction to the accident date). Although the vertical inventory of 134 Cs decreased between 2014 and 2017, the inventory in 2017 was larger than that expected. That was probably arose from the return of some portion of the high-concentration water mass along with the anticlockwise subarctic gyre current.

中文翻译：

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2017年夏季北太平洋西部亚北极地区福岛源放射性铯的活度浓度

2017 年在北太平洋西部亚北极地区测量了放射性铯的垂直剖面（ 134 Cs 和 137 Cs）。 134 Cs 的最高浓度来源于 2011 年福岛第一核电站事故，为 0.14 Bq m -3 （或衰减校正至事故日期后的 1.19 Bq m -3）。虽然2014-2017年134Cs的垂直库存有所下降，但2017年的库存大于预期。这可能是由于部分高浓度水团与逆时针的亚北极环流一起回流造成的。