¹²⁹I measurements on samples collected during GEOTRACES oceanographic missions in the Arctic Ocean in 2015 have provided the first synoptic ¹²⁹I sections across the Eurasian, Canada, and Makarov Basins. During the 1990s, increased discharges of ¹²⁹I from European nuclear fuel reprocessing plants produced a large, tracer spike whose passage through the Arctic Ocean has been followed by ¹²⁹I time series measurements over the past 25 years. Elevated ¹²⁹I levels measured over the Lomonosov and Alpha‐Mendeleyev Ridges in 2015 were associated with tracer labeled, Atlantic‐origin water bathymetrically steered by the ridge systems through the central Arctic while lower ¹²⁹I levels were evident in the more poorly ventilated basin interiors. ¹²⁹I levels of 200–400 × 10⁷ at/l measured in intermediate waters had increased by a factor of 10 in 2015 compared to 1994–1996 owing to the circulation of the 1990s, ¹²⁹I input spike. Comparisons of ¹²⁹I distributions between the mid‐1990s and 2015 delineate large scale circulation changes that occurred during the shift from a positive Arctic Oscillation and a cyclonic circulation regime in the mid‐1990s to anticyclonic circulation in 2015. The latter is characterized by a broadened Beaufort Gyre in the upper ocean, a weakened boundary current and partial mid‐depth, AW flow reversal in the southern Canada Basin. Tracer ¹²⁹I simulations using the applied circulation model, NAOSIM, agree with both historical ¹²⁹I results and recent GEOTRACES data sets, thereby supporting the present interpretation of the relationship of changes in arctic circulation to shifts in climate indices revealed by tracer ¹²⁹I distributions.

中文翻译：

---

不断变化的北冰洋：如何测量和建模129I分布指示1994年至2015年之间的环流基本变化

对2015年在北冰洋的GEOTRACES海洋学任务期间采集的样本进行的¹²⁹ I测量提供了横跨欧亚，加拿大和马卡洛夫盆地的第一条天气¹²⁹ I剖面。在1990年代，欧洲核燃料加工厂的¹²⁹ I排放量增加，产生了一个大的示踪剂尖峰，该尖峰穿过北冰洋，在过去25年中进行了¹²⁹ I时间序列测量。在2015年在罗蒙诺索夫和阿尔法-门捷列夫山脊上测得的¹²⁹ I水平升高与示踪剂标记的相关，这些示踪剂是由脊系统通过北极中部测深引导的大西洋原水，而较低的¹²⁹ I在通风较差的盆地内部，I水平很明显。由于1990年代的流通，2015年中间水域中¹²⁹ I的200–400×10 ⁷ at / l水平与1994–1994年相比增加了10倍，这是由于1990年代的流通造成的^。129 I输入峰值。对1990年代中期和2015年之间的¹²⁹ I分布进行的比较描述了从1990年代中期的积极的北极涛动和气旋环流转移到2015年的反气旋环流期间发生的大规模环流变化。后者的特征是范围扩大了上海的波弗特涡流，边界流减弱和加拿大南部盆地部分中深水流逆转。示踪剂¹²⁹使用应用的环流模型NAOSIM进行的I模拟与历史¹²⁹ I结果和最新的GEOTRACES数据集均吻合，从而支持对北极环流变化与示踪剂¹²⁹ I分布揭示的气候指数变化之间关系的当前解释。