Size-resolved simulations of the aerosol inorganic composition with the new hybrid dissolution solver HyDiS-1.0: description, evaluation and first global modelling results
Size-resolved simulations of the aerosol inorganic composition with the new hybrid dissolution solver HyDiS-1.0: description, evaluation and first global modelling results
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DOI：
10.5194/gmd-9-3875-2016
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发表时间：
2016-11-01
影响因子：
5.1
通讯作者：
Carslaw, Kenneth S.
中科院分区：
文献类型：
--
作者：
Benduhn, Francois;Mann, Graham W.;Carslaw, Kenneth S.
半挥发性无机气体如氨和硝酸在气溶胶水相中的溶解对大气气溶胶粒子的组成、吸湿特性和粒径分布有重要影响。由于数值稳定性和计算费用的固有问题，在全球模型中表示溶解是具有挑战性的。由于这个原因，经常采用简化的方法，许多模型将溶解视为平衡过程。在本文中，我们描述了新的溶解解算器HyDiS-1.0，这是全球尺寸分辨模拟气溶胶无机成分。求解器应用混合方法，该方法允许某些颗粒尺寸类别建立瞬时气体-颗粒平衡，而其他颗粒尺寸类别则根据时间（或动态）进行处理。通过使用几种定制的数值形式和决策标准，例如在平衡方法和动态方法之间根据时间和尺寸进行选择，可以以有竞争力的计算费用实现数值准确性。新的混合求解器具有数值稳定性跨越范围广泛的数值刚度条件内遇到的大气。对于氨和硝酸，HyDiS-1.0被发现是在一个完全动态的基准求解器非常好的协议。在海盐气溶胶的存在下，发现在高度污染的条件下，如果盐酸作为第三个半挥发性物种的一个有点大的偏差。我们目前的第一个结果的求解器的实施到一个全球性的气溶胶微物理和化学传输模型。我们发现，（1）新的求解器预测的硝酸盐和铵的表面浓度与欧洲，美国和东亚的观测结果合理一致，（2）假设气体-颗粒平衡的模型将无法捕获硝酸和氨分配到艾特肯模式大小的颗粒中，因此可能会错过一个重要的途径，通过该途径，二次粒子可能会增长到辐射和云相互作用的大小，新的混合求解器的计算费用是适度的，在这些模拟中的总计算时间的10%左右。
The dissolution of semi-volatile inorganic gases such as ammonia and nitric acid into the aerosol aqueous phase has an important influence on the composition, hygroscopic properties, and size distribution of atmospheric aerosol particles. The representation of dissolution in global models is challenging due to inherent issues of numerical stability and computational expense. For this reason, simplified approaches are often taken, with many models treating dissolution as an equilibrium process. In this paper we describe the new dissolution solver HyDiS-1.0, which was developed for the global size-resolved simulation of aerosol inorganic composition. The solver applies a hybrid approach, which allows for some particle size classes to establish instantaneous gas-particle equilibrium, whereas others are treated time dependently (or dynamically). Numerical accuracy at a competitive computational expense is achieved by using several tailored numerical formalisms and decision criteria, such as for the time-and size-dependent choice between the equilibrium and dynamic approaches. The new hybrid solver is shown to have numerical stability across a wide range of numerical stiffness conditions encountered within the atmosphere. For ammonia and nitric acid, HyDiS-1.0 is found to be in excellent agreement with a fully dynamic benchmark solver. In the presence of sea salt aerosol, a somewhat larger bias is found under highly polluted conditions if hydrochloric acid is represented as a third semi-volatile species. We present first results of the solver's implementation into a global aerosol microphysics and chemistry transport model. We find that (1) the new solver predicts surface concentrations of nitrate and ammonium in reasonable agreement with observations over Europe, the USA, and East Asia, (2) models that assume gas-particle equilibrium will not capture the partitioning of nitric acid and ammonia into Aitken-mode-sized particles, and thus may be missing an important pathway through which secondary particles may grow to radiation-and cloud-interacting size, and (3) the new hybrid solver's computational expense is modest, at around 10% of total computation time in these simulations.