Abstract Our understanding about the atmospheric dimethyl sulfide (DMS) and its influence to sea-to-air flux calculation in the Southern Ocean is still limited due to insufficient investigations. Herein, high-resolution shipboard underway simultaneous surface seawater and atmospheric DMS measurements were conducted in the Southern Ocean from February 23 to March 31, 2018. A larger variation of DMS levels was found in atmosphere compared with that in seawater. Remarkably, a large-scale area with high seawater and atmospheric DMS concentrations up to 27.9 nM and 3.92 ppbv, respectively, was investigated outside of Ross Sea sector. Atmospheric DMS levels were strongly impacted by wind speed and air mass convection. The relationship between atmospheric DMS and air mass exposure to oceanic chlorophyll varied greatly depending on the area of investigation. Some other regions with high DMS production capacity were examined as well beside those along the cruise tracks based on the results of positive correlations with high slopes and back trajectories. Moreover, significant uncertainty of sea-to-air DMS flux over the Southern Ocean could be caused by follows: (1) the selecting of different gas transfer coefficients; (2) the negative flux values calculated under high atmospheric DMS levels together with low seawater DMS concentrations; and (3) the greatly overestimated flux, approximately 47.1–76.9%, without considering the atmospheric DMS. This study highlights the urgent demand of high-resolution observations of atmospheric DMS over the Southern Ocean to estimate DMS emission with high accuracy.

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大气二甲基硫醚及其对南大洋海气通量计算的重要影响

摘要 由于调查不充分，我们对大气二甲基硫醚（DMS）及其对南大洋海气通量计算的影响的认识仍然有限。在此，2018 年 2 月 23 日至 3 月 31 日在南大洋进行了高分辨率舰载同时进行地表海水和大气 DMS 测量。与海水相比，发现大气中 DMS 水平的变化更大。值得注意的是，在罗斯海区以外调查了一个大范围的海水和大气 DMS 浓度分别高达 27.9 nM 和 3.92 ppbv 的区域。大气 DMS 水平受到风速和气团对流的强烈影响。大气 DMS 与大气暴露于海洋叶绿素之间的关系因调查区域而异。根据与高坡度和反向轨迹正相关的结果，除了巡航轨道沿线的区域外，还检查了其他一些具有高 DMS 生产能力的区域。此外，南大洋海空DMS通量的显着不确定性可能由以下原因引起：（1）不同气体传输系数的选择；(2) 在高大气 DMS 水平和低海水 DMS 浓度下计算的负通量值；(3) 在不考虑大气 DMS 的情况下，大大高估了通量，大约为 47.1-76.9%。