Carbon dynamics of the Weddell Gyre, Southern Ocean
Carbon dynamics of the Weddell Gyre, Southern Ocean
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DOI：
10.1002/2014gb005006
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发表时间：
2015-03-01
影响因子：
5.2
通讯作者：
Wanninkhof, Rik
中科院分区：
文献类型：
--
作者：
Brown, Peter J.;Jullion, Loic;Wanninkhof, Rik
通过最近围绕这个气候重要区域的三个全深度海洋学剖面，研究了威德尔环流内的碳积累及其跨环流边界的交换。将碳测量值与箱式逆分析的海洋环流传输估计相结合表明，与温暖深水（WDW）和威德尔海深水相关的深水传输主导着环流的碳预算，而双细胞垂直翻转环流导致上升流并将大量碳输送到深海。使用神经网络技术插值的历史海面 pCO(2) 观测结果证实，从反演得出的夏季净汇为 0.044 至 0.058 +/- 0.010 Pg C yr(-1)。然而，大小相似的冬季排气信号导致威德尔环流诊断出的年空气-海洋二氧化碳通量在统计上不显着，为 0.002 +/- 0.007 Pg C yr(-1)（1998-2011 年平均值）至 0.012 +/- 0.024 Pg C yr(-1)（2008-2010 年平均值）。表层碳平衡独立地源自原位生物地球化学测量，表明淡水输入和生物消减对表层海洋无机碳水平的降低程度超过了 WDW 夹带所增加的水平，导致每年碳汇估计为 0.033 +/- 0.021 Pg C yr(-1)。尽管吸收碳的效率相对低于全球海洋，但夏季威德尔环流抑制了冬季的排气信号，而其生物泵和深水形成是将自然和人为碳输送到深海的关键管道，在那里它们可以长期驻留。
The accumulation of carbon within the Weddell Gyre and its exchanges across the gyre boundaries are investigated with three recent full-depth oceanographic sections enclosing this climatically important region. The combination of carbon measurements with ocean circulation transport estimates from a box inverse analysis reveals that deepwater transports associated with Warm Deep Water (WDW) and Weddell Sea Deep Water dominate the gyre's carbon budget, while a dual-cell vertical overturning circulation leads to both upwelling and the delivery of large quantities of carbon to the deep ocean. Historical sea surface pCO(2) observations, interpolated using a neural network technique, confirm the net summertime sink of 0.044 to 0.058 +/- 0.010 Pg C yr(-1) derived from the inversion. However, a wintertime outgassing signal similar in size results in a statistically insignificant annual air-to-sea CO2 flux of 0.002 +/- 0.007 Pg C yr(-1) (mean 1998-2011) to 0.012 +/- 0.024 Pg C yr(-1) (mean 2008-2010) to be diagnosed for the Weddell Gyre. A surface layer carbon balance, independently derived from in situ biogeochemical measurements, reveals that freshwater inputs and biological drawdown decrease surface ocean inorganic carbon levels more than they are increased by WDW entrainment, resulting in an estimated annual carbon sink of 0.033 +/- 0.021 Pg C yr(-1). Although relatively less efficient for carbon uptake than the global oceans, the summertime Weddell Gyre suppresses the winter outgassing signal, while its biological pump and deepwater formation act as key conduits for transporting natural and anthropogenic carbon to the deep ocean where they can reside for long time scales.