Multiphase processes in the EC-Earth model and their relevance to the atmospheric oxalate, sulfate, and iron cycles
Multiphase processes in the EC-Earth model and their relevance to the atmospheric oxalate, sulfate, and iron cycles
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DOI：
10.5194/gmd-15-3079-2022
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发表时间：
2022-04
影响因子：
5.1
通讯作者：
S. Myriokefalitakis;Elisa Bergas-Massó;María Gonçalves-Ageitos;C. Pérez García-Pando;T. van Noije;Philipp Le Sager;A. Ito;E. Athanasopoulou;A. Nenes;M. Kanakidou;M. Krol;E. Gerasopoulos
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作者：
S. Myriokefalitakis;Elisa Bergas-Massó;María Gonçalves-Ageitos;C. Pérez García-Pando;T. van Noije;Philipp Le Sager;A. Ito;E. Athanasopoulou;A. Nenes;M. Kanakidou;M. Krol;E. Gerasopoulos
摘要。了解多相过程如何影响含铁气溶胶循环是预测海洋生物地球化学变化以及由此产生的对气候的反馈效应的关键。在这项工作中，采用具有气候 - 化学配置的EC - 地球地球系统模型，在纳入云滴和气溶胶水相中多相化学的综合表述后，模拟全球大气中的草酸（OXL）、硫酸盐（SO42 -）和铁（Fe）循环。该模型考虑了详细的气相化学方案、所有主要的气溶胶成分以及气体在气溶胶和大气水相中的分配。含铁气溶胶的溶解从动力学上考虑了溶液的酸度、草酸和辐射。模型中明确计算了气溶胶酸度，包括积聚模态和粗模态，考虑了涉及海盐和沙尘中的无机和地壳物质的热力学过程。利用EC - 地球模型以及由欧洲中期天气预报中心（ECMWF）的ERA - Interim再分析气象场驱动的独立模式下的模型大气成分组件，对当前条件（2000 - 2014年）进行了模拟。给出了计算出的全球收支情况，并展示和量化了（1）水相过程、（2）气溶胶溶解和（3）大气成分之间的联系。通过与现有观测结果的比较来支持模型结果。我们在EC - 地球模型中得到全球草酸净化学产量平均为12.615 ± 0.064 Tg yr−1，其中乙二醛是迄今为止草酸最重要的前体。与ERA - Interim模拟相比，大气动力学的差异以及EC - 地球模型中模拟的较弱氧化能力总体上导致草酸源降低约30%。另一方面，与该模型的先前版本相比，EC - 地球模型中对水相化学更明确的表述导致硫酸盐产量总体上提高约20%，但这仍然与大气观测结果高度相关。在EC - 地球模型中计算出的总铁溶解速率为0.806 ± 0.014 Tg yr−1，并添加到模型中来自沙尘和燃烧气溶胶的初级溶解铁（DFe）源（0.072 ± 0.001 Tg yr−1）。模拟的DFe浓度与现有观测结果相比令人满意，表明大气负荷约为0.007 Tg，导致进入全球海洋的总大气沉积通量为0.376 ± 0.005 Tg yr−1，这完全在文献报道的范围内。总之，这项工作是将EC - 地球模型发展成为一个地球系统模型的第一步，该模型具有对海洋生物地球化学组件完全交互式的生物可利用大气铁输入。
Abstract. Understanding how multiphase processes affect the iron-containing aerosol cycle is key to predicting ocean biogeochemistry changes and hence the feedback effects on climate. For this work, the EC-Earth Earth system model in its climate–chemistry configuration is used to simulate the global atmospheric oxalate (OXL), sulfate (SO42-), and iron (Fe) cycles after incorporating a comprehensive representation of the multiphase chemistry in cloud droplets and aerosol water. The model considers a detailed gas-phase chemistry scheme, all major aerosol components, and the partitioning of gases in aerosol and atmospheric water phases. The dissolution of Fe-containing aerosols accounts kinetically for the solution's acidity, oxalic acid, and irradiation. Aerosol acidity is explicitly calculated in the model, both for accumulation and coarse modes, accounting for thermodynamic processes involving inorganic and crustal species from sea salt and dust. Simulations for present-day conditions (2000–2014) have been carried out with both EC-Earth and the atmospheric composition component of the model in standalone mode driven by meteorological fields from ECMWF's ERA-Interim reanalysis. The calculated global budgets are presented and the links between the (1) aqueous-phase processes, (2) aerosol dissolution, and (3) atmospheric composition are demonstrated and quantified. The model results are supported by comparison to available observations. We obtain an average global OXL net chemical production of 12.615 ± 0.064 Tg yr−1 in EC-Earth, with glyoxal being by far the most important precursor of oxalic acid. In comparison to the ERA-Interim simulation, differences in atmospheric dynamics and the simulated weaker oxidizing capacity in EC-Earth overall result in a ∼ 30 % lower OXL source. On the other hand, the more explicit representation of the aqueous-phase chemistry in EC-Earth compared to the previous versions of the model leads to an overall ∼ 20 % higher sulfate production, but this is still well correlated with atmospheric observations. The total Fe dissolution rate in EC-Earth is calculated at 0.806 ± 0.014 Tg yr−1 and is added to the primary dissolved Fe (DFe) sources from dust and combustion aerosols in the model (0.072 ± 0.001 Tg yr−1). The simulated DFe concentrations show a satisfactory comparison with available observations, indicating an atmospheric burden of ∼0.007 Tg, resulting in an overall atmospheric deposition flux into the global ocean of 0.376 ± 0.005 Tg yr−1, which is well within the range reported in the literature. All in all, this work is a first step towards the development of EC-Earth into an Earth system model with fully interactive bioavailable atmospheric Fe inputs to the marine biogeochemistry component of the model.