Field observations suggest that oceanic emissions of dimethylsulfide (DMS) may play a dominant role in the production of Arctic aerosols and clouds, and therefore modulate the surface irradiance, during spring and summer. DMS is produced not only in the water column, but also in various sea‐ice habitats. The ongoing recession of Arctic sea ice is expected to enhance DMS emissions, but the magnitude of this increase is highly uncertain. Here we investigate the spatio‐temporal variability in bottom‐ice and sea‐surface DMS concentrations and fluxes using a regional sea ice‐ocean physical‐biogeochemical model. Model results indicate that the observed accelerated decline of Arctic sea‐ice extent since the beginning of the 21st century is associated with upward trends in May‐August pan‐Arctic‐average sea‐surface DMS concentration and sea‐to‐air DMS flux. On the other hand, strong interannual variability and statistically insignificant trends are found for bottom‐ice DMS concentration and ice‐to‐sea DMS flux, owing to the counteracting effects of the shrinking horizontal extent and the vertical thinning of sea ice on ice algal production. The pan‐Arctic DMS climatology products based on model simulation and satellite algorithms provide dynamically‐based spatial details that are absent in the in situ measurement‐based climatology due to limited spatio‐temporal data coverage and inevitable extrapolation bias. Lastly, model results indicate that the bottom‐ice DMS and its precursor dimethylsulfoniopropionate production can be the only local source of oceanic DMS emissions into the atmosphere during May prior to pelagic blooms, suggesting it may be a key component of the biological control on Arctic climate at that time.

中文翻译：

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1979-2015 年期间北极模拟底冰和海面二甲基硫醚浓度和通量的时空变化

实地观察表明，二甲基硫醚 (DMS) 的海洋排放可能在北极气溶胶和云的产生中起主导作用，因此在春季和夏季调节地表辐照度。DMS 不仅在水体中产生，而且在各种海冰栖息地中产生。北极海冰的持续衰退预计将增加 DMS 排放，但这种增加的幅度非常不确定。在这里，我们使用区域海冰-海洋物理-生物地球化学模型研究底层冰和海面 DMS 浓度和通量的时空变异性。模型结果表明，自 21 世纪初以来，观测到的北极海冰范围加速下降与 5-8 月泛北极平均海面 DMS 浓度和海空 DMS 通量的上升趋势有关。另一方面，由于水平范围缩小和海冰垂直变薄对冰藻生产的抵消作用，底冰 DMS 浓度和冰-海 DMS 通量存在强烈的年际变化和统计上不显着的趋势。 . 由于有限的时空数据覆盖和不可避免的外推偏差，基于模型模拟和卫星算法的泛北极 DMS 气候学产品提供了基于动态的空间细节，这些细节在基于现场测量的气候学中是不存在的。最后，模型结果表明，冰底 DMS 及其前体二甲基磺基丙酸盐的产生可能是 5 月远洋水华前海洋 DMS 排放到大气中的唯一本地来源，