The impact of Southern Ocean residual upwelling on atmospheric CO2 on centennial and millennial timescales
The impact of Southern Ocean residual upwelling on atmospheric CO2 on centennial and millennial timescales
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DOI：
10.1007/s00382-016-3163-y
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发表时间：
2017-03-01
期刊：
影响因子：
4.6
通讯作者：
Marshall, David P.
中科院分区：
文献类型：
--
作者：
Lauderdale, Jonathan M.;Williams, Richard G.;Marshall, David P.
南大洋通过热量和碳交换在气候变化中发挥着关键作用，并为全球深海与大气层沟通提供了主要窗口。有一个广泛的重点是解释大气中的CO2变化在南大洋的风强迫的变化。在这里，我们开发了一种动态驱动的指标--残余上升流，通过确定与深海的交流来测量南大洋动态在百年到千年时间尺度上对大气二氧化碳的主要影响。该指标包含了风和海气浮力对上下翻转单元的综合净效应，这些单元被用来解释当今大气CO2的变化和冰川-间冰期的变化。该指标的技能进行评估，采用套件的理想化的海洋模型实验，包括参数化和明确模拟的漩涡，与在线地球化学和集成为10,000年的平衡。残余上升流的增加通过加强大气和深海之间的交流，以通常1-1.5 ppm/10（6）m（3）s（-1）的速率驱动大气CO2升高。该指标可用于解释南大洋动力学对自然碳循环和大气CO2的长期影响，以及其他指标，例如涉及预制营养物的比例和海冰覆盖范围。
The Southern Ocean plays a pivotal role in climate change by exchanging heat and carbon, and provides the primary window for the global deep ocean to communicate with the atmosphere. There has been a widespread focus on explaining atmospheric CO2 changes in terms of changes in wind forcing in the Southern Ocean. Here, we develop a dynamically-motivated metric, the residual upwelling, that measures the primary effect of Southern Ocean dynamics on atmospheric CO2 on centennial to millennial timescales by determining the communication with the deep ocean. The metric encapsulates the combined, net effect of winds and air-sea buoyancy forcing on both the upper and lower overturning cells, which have been invoked as explaining atmospheric CO2 changes for the present day and glacial-interglacial changes. The skill of the metric is assessed by employing suites of idealized ocean model experiments, including parameterized and explicitly simulated eddies, with online biogeochemistry and integrated for 10,000 years to equilibrium. Increased residual upwelling drives elevated atmospheric CO2 at a rate of typically 1-1.5 parts per million/10(6) m(3) s(-1) by enhancing the communication between the atmosphere and deep ocean. This metric can be used to interpret the long-term effect of Southern Ocean dynamics on the natural carbon cycle and atmospheric CO2, alongside other metrics, such as involving the proportion of preformed nutrients and the extent of sea ice cover.