Wind Speed and Sea State Dependencies of Air-Sea Gas Transfer: Results From the High Wind Speed Gas Exchange Study (HiWinGS)
Wind Speed and Sea State Dependencies of Air-Sea Gas Transfer: Results From the High Wind Speed Gas Exchange Study (HiWinGS)
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DOI：
10.1002/2017jc013181
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发表时间：
2017-10-01
影响因子：
3.6
通讯作者：
Pascal, R. W.
中科院分区：
文献类型：
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作者：
Blomquist, B. W.;Brumer, S. E.;Pascal, R. W.
各种物理机制共同负责促进通过大气-海洋界面的湍流过程的海气传输。这些机制的性质和相对重要性随着风速的增加而演变。理论和建模方法正在取得进展，但在高风速下的观测数据数量有限，阻碍了对这些努力的评估。HiWinGS项目在每小时平均风速高达24 m s（-1）和有效波高为8 m的条件下，成功测量了气体传输系数（k（660））和重合的波浪统计数据。二氧化碳（CO2）和二甲硫醚（DMS）的k（660）的测量结果表明，相对于10米中性风速（U-10 N）的增加趋势，以下形式的幂律关系：k660 CO2近似于U10 N1.68和k660 dms近似于U10 N1.33。在7次高风速事件中，CO2输运对波浪破碎强度的响应是复杂的，随风海接近充分发展，k660 CO2增加。DMS未观察到类似的反应。这些结果证实了破碎波和气泡喷射机制在促进CO2传输中的重要性。耦合海洋-大气响应实验气体传输算法（COAREG版本）的修改版本。3.5），结合了一个依赖于海况的气泡介导的传输计算，成功地再现了两种气体的观测k（660）与风速的平均趋势。在HiWinGS过程中，没有观察到大波浪对气体传输的显著抑制，这与之前两个现场项目的结果相反。
A variety of physical mechanisms are jointly responsible for facilitating air-sea gas transfer through turbulent processes at the atmosphere-ocean interface. The nature and relative importance of these mechanisms evolves with increasing wind speed. Theoretical and modeling approaches are advancing, but the limited quantity of observational data at high wind speeds hinders the assessment of these efforts. The HiWinGS project successfully measured gas transfer coefficients (k(660)) with coincident wave statistics under conditions with hourly mean wind speeds up to 24 m s(-1) and significant wave heights to 8 m. Measurements of k(660) for carbon dioxide (CO2) and dimethylsulfide (DMS) show an increasing trend with respect to 10 m neutral wind speed (U-10N), following a power law relationship of the form: k660CO2 approximate to U10N1.68 and k660dms approximate to U10N1.33. Among seven high wind speed events, CO2 transfer responded to the intensity of wave breaking, which depended on both wind speed and sea state in a complex manner, with k660CO2 increasing as the wind sea approaches full development. A similar response is not observed for DMS. These results confirm the importance of breaking waves and bubble injection mechanisms in facilitating CO2 transfer. A modified version of the Coupled Ocean-Atmosphere Response Experiment Gas transfer algorithm (COAREG ver. 3.5), incorporating a sea state-dependent calculation of bubble-mediated transfer, successfully reproduces the mean trend in observed k(660) with wind speed for both gases. Significant suppression of gas transfer by large waves was not observed during HiWinGS, in contrast to results from two prior field programs.