Parameterizing bubble‐mediated air‐sea gas exchange and its effect on ocean ventilation
Parameterizing bubble‐mediated air‐sea gas exchange and its effect on ocean ventilation
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DOI：
10.1002/gbc.20080
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发表时间：
2013-09
影响因子：
5.2
通讯作者：
Jun‐Hong Liang;C. Deutsch;J. McWilliams;B. Baschek;P. Sullivan;David Chiba
中科院分区：
文献类型：
--
作者：
Jun‐Hong Liang;C. Deutsch;J. McWilliams;B. Baschek;P. Sullivan;David Chiba
气泡在大气和海洋之间的气体交换中起着重要的作用，它改变了交换的速率和平衡的气体饱和状态。我们开发了一种用于地球系统模型的气泡中介气体通量的参数化。该参数化是从海洋边界层的一个机械模型中得出的，该模型模拟了一定风速范围内的湍流和气泡的尺寸谱，并与其他已发表的公式进行了比较。气泡引起的表面过饱和度随着风速的增加而迅速增加，在给定的风速下与温度成反比，使得气泡在深海通风区域的影响最大。在高纬度表面水域中，气泡引起的过饱和补偿了表面冷却引起的很大一部分不饱和。利用一个全球海洋输送模式，我们表明，该参数化重现了在大西洋和太平洋深处观测到的惰性气体Ar的饱和率分布。气泡引起的深海Ar过饱和度随气体溶解度的不同而不同，从二氧化碳等可溶气体的∼0.7%到氮气等较难溶的气体的∼1.7%不等。气泡诱导的过饱和度对于氧气等生物活性气体可能是重要的。
Bubbles play an important role in the exchange of gases between the atmosphere and ocean, altering both the rate of exchange and the equilibrium gas saturation state. We develop a parameterization of bubble‐mediated gas fluxes for use in Earth system models. The parameterization is derived from a mechanistic model of the oceanic boundary layer that simulates turbulent flows and the size spectrum of bubbles across a range of wind speeds and is compared against other published formulations. Bubble‐induced surface supersaturation increases rapidly with wind speed and is inversely related to temperature at a given wind speed, making the effect of bubbles greatest in regions that ventilate the deep ocean. The bubble‐induced supersaturation in high‐latitude surface waters compensates a substantial fraction of the undersaturation caused by surface cooling. Using a global ocean transport model, we show that this parameterization reproduces observed saturation rate profiles of the noble gas Argon in the deep Atlantic and Pacific Oceans. The abyssal argon supersaturation caused by bubbles varies according to gas solubility, ranging from ∼0.7% for soluble gases like CO2 to ∼1.7% for less soluble gases such as N2. Bubble‐induced supersaturation may be significant for biologically active gases such as oxygen.