Interannual variability of Arctic sea ice export into the East Greenland Current
Interannual variability of Arctic sea ice export into the East Greenland Current
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DOI：
10.1029/2010jc006227
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发表时间：
2010-12
影响因子：
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通讯作者：
K. Cox;J. Stanford;A. J. McVicar;E. Rohling;K. Heywood;S. Bacon;M. Bolshaw;P. Dodd;S. Rosa
中科院分区：
文献类型：
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作者：
K. Cox;J. Stanford;A. J. McVicar;E. Rohling;K. Heywood;S. Bacon;M. Bolshaw;P. Dodd;S. Rosa
[1]自20世纪50年代以来的观测表明，北极气候系统正在随着全球气温的上升而发生变化。这些变化包括水文循环加剧、北极海冰减少和格陵兰冰川融化增加。在这里，我们使用新的δ 18 O数据从东格陵兰流系统在告别角和丹麦海峡，以确定淡水成分的相对比例的东格陵兰流和东格陵兰沿岸流。通过这些新数据与历史研究的比较，我们可以深入了解北极淡水平衡的变化。我们检测到三个关键的变化，这些是（1）在20世纪90年代后期转向较轻的值，这可能表明格陵兰冰川融化增加或海冰融化混合物减少;（2）在2005年短期转向10‰重的值，随后（3）在2008年回到历史平均值。后者的波动反映了短期的海冰融水的急剧上升和下降，除了东格陵兰电流系统。我们推断，这异常大的海冰融水的夹杂物是由于短期的北极海冰出口高峰通过弗拉姆海峡。因此，我们的研究结果表明，东格陵兰洋流系统中携带的淡水容易受到上游淡水平衡的短期高幅度变化的影响，这可能会通过抑制北大西洋深水形成对全球温盐环流产生重要影响。
[1] Observations since the 1950s suggest that the Arctic climate system is changing in response to rising global air temperatures. These changes include an intensified hydrological cycle, Arctic sea ice decline, and increasing Greenland glacial melt. Here we use new δ18O data from the East Greenland Current system at Cape Farewell and Denmark Strait to determine the relative proportions of the freshwater components within the East Greenland Current and East Greenland Coastal Current. Through the comparison of these new data with historical studies, we gain insight into the changing Arctic freshwater balance. We detect three key shifts in the net freshwater component δ18O values, these are (1) a shift to lighter values in the late 1990s that possibly indicates an increased Greenland glacial melt or a reduced sea ice melt admixture and (2) a short-term shift to a ∼10‰ heavier value in 2005 followed by (3) a shift back to the historic average value in 2008. The latter fluctuation reflects a short-term dramatic rise and fall of sea ice meltwater addition into the East Greenland Current system. We infer that this anomalously large inclusion of sea ice meltwater resulted from a short-term peak in Arctic sea ice export via Fram Strait. Our findings, therefore, suggest that the freshwater carried in the East Greenland Current system is susceptible to short-term, high-amplitude changes in the upstream freshwater balance, which may have important ramifications for the global thermohaline circulation through the suppression of deep water formation in the North Atlantic.