Air-sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed
Air-sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed
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DOI：
10.5194/acp-13-11073-2013
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发表时间：
2013-01-01
影响因子：
6.3
通讯作者：
Saltzman, E. S.
中科院分区：
文献类型：
--
作者：
Bell, T. G.;De Bruyn, W.;Saltzman, E. S.
2011年6月/7月，在北大西洋水华区进行了涡动协方差二甲基硫（DMS）海气通量和海水浓度的船上测量。在风速高达11 m s（-1）时，气体传输系数（k（660））与平均水平风速呈线性关系。在较高的风速下，k（660）和风速之间的关系减弱。在大风，测得的DMS通量低于预测的基础上，风速和界面应力之间的线性关系外推从低到中等风速。相反，显热的传递系数没有表现出这种效果。在较高的风速下，海-气通量的明显抑制似乎与海况有关，这是由船上的波浪测量结果确定的。这些观察结果与长波抑制近水面湍流，减少界面气体传输的想法是一致的。这种效应对于DMS比对于诸如CO2的不太可溶的气体更容易观察到，因为DMS的海气交换在高风速条件下由界面而不是气泡介导的气体转移控制。
Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k(660)) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s(-1). At higher wind speeds the relationship between k(660) and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air-sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air-sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.