Natural aerosols are an important, yet understudied, part of the Arctic climate system. Natural marine biogenic aerosol components (e.g., methanesulfonic acid, MSA) are becoming increasingly important due to changing environmental conditions. In this study, we combine in situ aerosol observations with atmospheric transport modeling and meteorological reanalysis data in a data-driven framework with the aim to (1) identify the seasonal cycles and source regions of MSA, (2) elucidate the relationships between MSA and atmospheric variables, and (3) project the response of MSA based on trends extrapolated from reanalysis variables and determine which variables are contributing to these projected changes. We have identified the main source areas of MSA to be the Atlantic and Pacific sectors of the Arctic. Using gradient-boosted trees, we were able to explain 84% of the variance and find that the most important variables for MSA are indirectly related to either the gas- or aqueous-phase oxidation of dimethyl sulfide (DMS): shortwave and longwave downwelling radiation, temperature, and low cloud cover. We project MSA to undergo a seasonal shift, with non-monotonic decreases in April/May and increases in June-September, over the next 50 years. Different variables in different months are driving these changes, highlighting the complexity of influences on this natural aerosol component. Although the response of MSA due to changing oceanic variables (sea surface temperature, DMS emissions, and sea ice) and precipitation remains to be seen, here we are able to show that MSA will likely undergo a seasonal shift solely due to changes in atmospheric variables.

天然气溶胶是北极气候系统的重要组成部分，但尚未得到充分研究。由于环境条件的变化，天然海洋生物气溶胶成分（例如甲磺酸、MSA）变得越来越重要。在本研究中，我们在数据驱动的框架中将原位气溶胶观测与大气传输模型和气象再分析数据相结合，目的是（1）确定MSA的季节周期和源区，（2）阐明MSA和MSA之间的关系。大气变量，(3) 根据再分析变量推断的趋势预测 MSA 的响应，并确定哪些变量导致这些预测的变化。我们已确定海事安全的主要来源地区是北极的大西洋和太平洋地区。使用梯度增强树，我们能够解释 84% 的方差，并发现 MSA 最重要的变量与二甲硫醚 (DMS) 的气相或水相氧化间接相关：短波和长波下降辐射、温度和低云量。我们预计，未来 50 年，MSA 将经历季节性变化，四月/五月非单调减少，六月至九月增加。不同月份的不同变量正在推动这些变化，凸显了对这种天然气溶胶成分影响的复杂性。尽管 MSA 对海洋变量（海面温度、DMS 排放和海冰）和降水变化的响应仍有待观察，但在这里我们能够表明，MSA 很可能仅仅由于大气变量的变化而经历季节性变化。