ATMOCHEM - Secondary organic aerosol production in the lower free troposphere over western Europe

最近的研究表明，一个显着的大量的二次有机气溶胶（SOA）存在于对流层中低层的大部分，无论是现在还是过去。因此，对这一重要的气溶胶部分的基本了解对于评估气溶胶（有机和无机）对过去和未来气候变化的净影响至关重要。大多数最近的模型系统地低估了SOA在大气中的质量，可能是由于其生产的不正确的经验参数化。为了在这一问题上取得进展，迫切需要专门研究进程。鉴于其对气候问题的重要性，需要深入探讨阿尔卑斯冰芯档案中保存的SOA的长期趋势。在这种情况下，该建议旨在（1）了解文件仍然很少的成核/凝结过程，（2）评估这些过程相对于对流层内不同高度处SOA总质量的相对重要性，（三）定量分析高山冰芯中SOA的长期变化趋势，从而推断其控制原因。在三个山区开展实地活动（气溶胶的物理和化学特性，可能是SOA的前体），沿着运输化学模拟和阿尔卑斯冰芯调查。气溶胶物理测量与大气化学/气溶胶模型的模拟相结合，以量化整个对流层成核/凝结的作用，迄今为止，在大气观测和建模之间的综合研究中从未涉及过。一个连续的长期趋势的SOA推断从高山冰芯和支持的放射性碳约束将首次记录。这种尝试也包括HULIS被怀疑是SOA贡献者的主要贡献者之一。

Recent studies suggest a significant large abundance of secondary organic aerosol (SOA) present in a large part of the low and middle troposphere, both, for present-day as well as over the past. A basic understanding of this important aerosol fraction is therefore crucial to evaluate the net impact of aerosol (organic and inorganic) on past and future climate change. Most of very recent models systematically underestimate the mass of SOA present in the atmosphere, likely due to incorrect empirical parameterizations of its production. To progress on this question, studies dedicated to processes are urgently needed. Given its importance for climate issues, the long term trend of SOA preserved in the Alpine ice core archive needs to be profoundly explored. In this context, the proposal aims at (1) to understand nucleation/condensation processes for which documentation remains scarce, (2) to evaluate the relative importance of these processes with respect to the total mass of SOA present at different altitudes within the troposphere, (3) to quantify the long term trend of SOA from Alpine ice cores thereby inferring its controlling cause.The proposal approach combines intensive atmospheric field campaigns (physical and chemical aerosols properties, likely precursors of SOA) at three mountain sites, along with transport-chemistry simulations and Alpine ice cores investigations. The coupling of the aerosol physical measurements with the simulations from a atmosphere-chemistry/aerosol model to quantify the role of nucleation/condensation throughout the troposphere has never been addressed so far in a combined study between atmospheric observations and modelling. A continuous long term trend of SOA inferred from alpine ice core and backed up by radiocarbon constraints will be documented for the first time. This attempt includes also HULIS suspected to be one of the major contributor to the mass of SOA contributor.