The Arctic Ocean plays an important role in global climate and global warming through freshwater and heat exchange with subarctic waters. A better understanding of circulation time scales in the Arctic Ocean is essential to predict changes in climate and biogeochemical cycling in the Arctic Ocean. I and Cs, which have been discharged from the nuclear fuel-reprocessing facilities, have been employed to determine the time scale of the circulation in the Arctic Ocean. However, its temporal change has not been understood well. In 2017, 2019, and 2020, we measured I and Cs in the Canada Basin in the Arctic Ocean. Using our new and historical data, we discuss temporal changes in the circulation in the basin between 1993 and 2020. The tracer ages derived from the I/Cs ratio indicate that the transport of the Atlantic water into the Canada Basin was accelerated in 2020. This is consistent with results of recent studies that indicated the intensified inflow of the Atlantic water into the eastern Arctic Ocean in the late 2010s, which is termed “atlantification”. Our results confirmed the “atlantification” in the Canada Basin by temporal changes in the transient tracers for the first time.

中文翻译：

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1993年至2020年北冰洋加拿大海盆碘129和放射性铯的时间变化

北冰洋通过与亚北极水域的淡水和热交换，在全球气候和全球变暖中发挥着重要作用。更好地了解北冰洋环流时间尺度对于预测北冰洋气候和生物地球化学循环的变化至关重要。从核燃料后处理设施排出的 I 和 Cs 已被用来确定北冰洋环流的时间尺度。然而，它的时间变化尚未得到很好的理解。 2017年、2019年和2020年，我们测量了北冰洋加拿大盆地的I和Cs。利用我们的新数据和历史数据，我们讨论了 1993 年至 2020 年间流域环流的时间变化。从 I/Cs 比率得出的示踪剂年龄表明，2020 年大西洋水向加拿大盆地的输送加速了。这与最近的研究结果一致，该研究表明大西洋海水在2010年代后期流入北冰洋东部，这被称为“大西洋化”。我们的结果首次通过瞬态示踪剂的时间变化证实了加拿大盆地的“大西洋化”。