Decadal Changes in Bomb-Produced Radiocarbon in the Pacific Ocean from the 1990s to 2000s
Decadal Changes in Bomb-Produced Radiocarbon in the Pacific Ocean from the 1990s to 2000s
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DOI：
10.1017/s0033822200048554
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发表时间：
2013-05
期刊：
影响因子：
8.3
通讯作者：
Y. Kumamoto;A. Murata;T. Kawano;S. Watanabe;M. Fukasawa
中科院分区：
文献类型：
--
作者：
Y. Kumamoto;A. Murata;T. Kawano;S. Watanabe;M. Fukasawa
在本世纪头十年，沿着太平洋世界海洋环流实验的路线，在7次重访航次中测量了溶解无机碳中的放射性碳。对1990年代和2000年代沿这些线的14C数据进行比较，发现温跃层中14C浓度的年代际变化，其中大部分是由于炸弹产生的14C的时间变化。亚北极和赤道地区14C炸弹的垂直剖面和垂直综合库存没有明显变化。在南部副热带地区，从表层到∼500m深处，14C在上层温跃层中降低。相反，在∼500m以下的下层温跃层中，14C含量增加。14C变化的相反方向导致了14C炸弹总库存的微小时间变化。另一方面，由于上层温跃层中14℃的下降，西北副热带地区的水柱库存显著减少。14C弹的这些年代际变化表明，西北副热带地区温跃层环流的周转时间比南亚副热带地区快，并暗示着14C弹从北太平洋到其他盆地的跨流域输送。
In the 2000s, radiocarbon in dissolved inorganic carbon was measured during 7 revisit cruises along the lines of the World Ocean Circulation Experiment in the Pacific Ocean. Comparison of 14C data along these lines from the 1990s and 2000s revealed decadal changes of 14C concentration in the thermocline, most of which were due to temporal changes in the bomb-produced 14C. Vertical profiles and vertical-integrated inventories of the bomb 14C in the subarctic and equatorial regions did not change appreciably. In the southern subtropical region, 14C decreased in the upper thermocline from the surface to ∼500 m depth. In contrast, 14C increased in the lower thermocline below ∼500 m depth. The opposing directions in 14C change resulted in small temporal changes in the total inventory of bomb 14C. On the other hand, the water-column inventory significantly decreased in the northwestern subtropical region due to the 14C decrease in the upper thermocline. These decadal changes in bomb 14C indicate that the turnover time of thermocline circulation in the northwestern subtropical region is faster than that in the southern subtropical region, and imply an interbasin transport of bomb 14C from the North Pacific to other basins.