Bubble size distributions ranging from 0.5 to 125 μm radius were measured optically during high winds of 13 m s−1 and large-scale wave breaking as part of the Southern Ocean Gas Exchange Experiment. Very small bubbles with radii less than 60 µm were measured at 6–9 m depth using optical measurements of the near-forward volume scattering function and critical scattering angle for bubbles (∼80°). The bubble size distributions generally followed a power law distribution with mean slope values ranging from 3.6 to 4.6. The steeper slopes measured here were consistent with what would be expected near the base of the bubble plume. Bubbles, likely stabilized with organic coatings, were present for time periods on the order of 10–100 s at depths of 6–9 m. Here, relatively young seas, with an inverse wave age of approximately 0.88 and shorter characteristic wave scales, produced lower bubble concentrations, shallower bubble penetration depths, and steep bubble size distribution slopes. Conversely, older seas, with an inverse wave age of 0.70 and longer characteristic wave scales, produced relatively higher bubble concentrations penetrating to 15 m depth, larger bubble sizes, and shallower bubble size distribution slopes. When extrapolated to 4 m depth using a previously published bubble size distribution, our estimates suggest that the deeply penetrating small bubbles measured in the Southern Ocean supplied ∼36% of the total void fraction and likely contributed to the transfer and supersaturation of low-solubility gases.
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机译：作为南部海洋气体交换实验的一部分，在13 m s-1的强风和大范围的波浪破裂期间，光学测量了半径范围从0.5到125μm的气泡尺寸分布。使用近前体积散射函数和气泡的临界散射角（约80°）的光学测量结果，在6–9 m深度处测量了半径小于60 µm的非常小的气泡。气泡大小分布通常遵循幂律分布，平均斜率范围为3.6至4.6。此处测得的陡峭斜率与气泡羽流底部附近的预期斜率一致。在6–9 m的深度，气泡可能存在约10–100 s的时间，可能被有机涂层稳定。在这里，相对年轻的海域，其逆波年龄约为0.88，特征波标较短，产生的气泡浓度较低，气泡穿透深度较浅，气泡尺寸分布斜率较陡。相反，逆浪年龄为0.70且特征波长较长的较老海产生的较高气泡浓度渗透到15 m深度，气泡尺寸较大，气泡尺寸分布斜率较浅。根据先前公布的气泡大小分布推算到4 m的深度时，我们的估计表明，在南大洋测得的深层渗透小气泡提供了约36％的总空隙率，并可能导致了低溶解度气体的转移和过饱和。
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