Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model
Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model
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DOI：
10.5194/acp-9-1747-2009
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发表时间：
2008-06
影响因子：
6.3
通讯作者：
R. Makkonen;A. Asmi;H. Korhonen;H. Kokkola;S. Järvenoja;P. Räisänen;K. Lehtinen;A. Laaksonen;V. Kerminen;H. Järvinen;U. Lohmann;R. Bennartz;J. Feichter;M. Kulmala
中科院分区：
文献类型：
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作者：
R. Makkonen;A. Asmi;H. Korhonen;H. Kokkola;S. Järvenoja;P. Räisänen;K. Lehtinen;A. Laaksonen;V. Kerminen;H. Järvinen;U. Lohmann;R. Bennartz;J. Feichter;M. Kulmala
抽象的。对全球气溶胶-气候模式ECHAM 5-HAM进行了改进，以改善边界层中新粒子形成的代表性。激活型成核机制被引入到产生观测到的成核率在低对流层。建立了一个简单、计算效率高的生物源二次有机气溶胶（BSOA）形成模式。在这里，我们研究的气溶胶和云滴数浓度（CDNC），这些添加的敏感性。激活型成核显着增加气溶胶数浓度的边界层。粒子数浓度的增加对云滴数浓度也有显著的影响，因此对云的性质也有显著的影响。我们使用2×10−7s−1、2×10−6s−1和2×10−5s−1的活化成核系数值进行计算，以评估对该参数的敏感性。对于BSOA，我们使用产率0.025、0.07和0.15来估计可用于缩合的单萜氧化产物的量。混合BSOA形成方案诱导大的区域变化的有机碳的粒径分布，从而影响粒子的光学特性和云滴数浓度的本地。虽然激活型成核提高了模拟气溶胶数浓度的边界层，使用一个全球性的激活系数通常会导致高估的气溶胶数。高估也可能源于对一次排放量的低估。
Abstract. The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce observed nucleation rates in the lower troposphere. A simple and computationally efficient model for biogenic secondary organic aerosol (BSOA) formation was implemented. Here we study the sensitivity of the aerosol and cloud droplet number concentrations (CDNC) to these additions. Activation-type nucleation significantly increases aerosol number concentrations in the boundary layer. Increased particle number concentrations have a significant effect also on cloud droplet number concentrations and therefore on cloud properties. We performed calculations with activation nucleation coefficient values of 2×10−7s−1, 2×10−6s−1 and 2×10−5s−1 to evaluate the sensitivity to this parameter. For BSOA we have used yields of 0.025, 0.07 and 0.15 to estimate the amount of monoterpene oxidation products available for condensation. The hybrid BSOA formation scheme induces large regional changes to size distribution of organic carbon, and therefore affects particle optical properties and cloud droplet number concentrations locally. Although activation-type nucleation improves modeled aerosol number concentrations in the boundary layer, the use of a global activation coefficient generally leads to overestimation of aerosol number. Overestimation can also arise from underestimation of primary emissions.