Nicholson Sarah-Anne, Whitt Daniel B, Fer Ilker, du Plessis Marcel D, Lebéhot Alice D, Swart Sebastiaan, Sutton Adrienne J, Monteiro Pedro M S
Southern Ocean Carbon-Climate Observatory (SOCCO), CSIR, Cape Town, South Africa.
National Center for Atmospheric Research, Boulder, CO, USA.
Nat Commun. 2022 Jan 10;13(1):158. doi: 10.1038/s41467-021-27780-w.
The subpolar Southern Ocean is a critical region where CO outgassing influences the global mean air-sea CO flux (F). However, the processes controlling the outgassing remain elusive. We show, using a multi-glider dataset combining F and ocean turbulence, that the air-sea gradient of CO (∆pCO) is modulated by synoptic storm-driven ocean variability (20 µatm, 1-10 days) through two processes. Ekman transport explains 60% of the variability, and entrainment drives strong episodic CO outgassing events of 2-4 mol m yr. Extrapolation across the subpolar Southern Ocean using a process model shows how ocean fronts spatially modulate synoptic variability in ∆pCO (6 µatm average) and how spatial variations in stratification influence synoptic entrainment of deeper carbon into the mixed layer (3.5 mol m yr average). These results not only constrain aliased-driven uncertainties in F but also the effects of synoptic variability on slower seasonal or longer ocean physics-carbon dynamics.
南大洋亚极地地区是一个关键区域，其中二氧化碳的释放影响着全球平均海气二氧化碳通量（F）。然而，控制这种释放的过程仍然难以捉摸。我们利用一个结合了F和海洋湍流的多滑翔器数据集表明，二氧化碳的海气梯度（∆pCO）通过两个过程受到天气尺度风暴驱动的海洋变率（20微巴，1 - 10天）的调制。埃克曼输运解释了60%的变率，并且夹卷作用驱动了2 - 4摩尔每平方米每年的强烈间歇性二氧化碳释放事件。使用一个过程模型对南大洋亚极地地区进行外推，展示了海洋锋面如何在空间上调制∆pCO中的天气尺度变率（平均6微巴），以及分层的空间变化如何影响深层碳向混合层的天气尺度夹卷（平均3.5摩尔每平方米每年）。这些结果不仅限制了F中由混淆驱动的不确定性，还限制了天气尺度变率对较慢的季节性或更长时间的海洋物理 - 碳动力学的影响。
