FORest Canopy Atmosphere Transfer (FORCAsT) 1.0: a 1-D model of biosphere-atmosphere chemical exchange
FORest Canopy Atmosphere Transfer (FORCAsT) 1.0: a 1-D model of biosphere-atmosphere chemical exchange
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DOI：
10.5194/gmd-8-3765-2015
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发表时间：
2015-01-01
影响因子：
5.1
通讯作者：
Steiner, A. L.
中科院分区：
文献类型：
--
作者：
Ashworth, K.;Chung, S. H.;Steiner, A. L.
生物圈与大气层之间的相互作用在控制大气组成方面发挥着关键作用，调节臭氧和气溶胶等关键物种的浓度，从而影响空气质量和气候。反应性痕量气体及其氧化产物（气相和颗粒相）的交换在该过程中特别重要。FORCAsT（FORest Canopy Atmosphere Transfer）1-D模式是为了研究挥发性有机化合物（VOCs）及其氧化产物在森林冠层内外大气中的排放、沉积、化学和传输而开发的。我们包括一个平衡分区计划，使FORCAST目前能够模拟形成的二次有机气溶胶（SOA）在森林环境中的VOC氧化的少数冠层模型之一。我们评估的能力FORCAsT重现观察到的浓度的关键气相物种和报告建模SOA浓度内和以上的混交林在密歇根大学生物站（UMBS）在社区大气-生物圈相互作用实验（CABINEX）在2009年夏天的实地活动。我们研究了两种不同的气相化学机制对模拟浓度的短期初级排放物，如异戊二烯和单萜，及其氧化产物的影响。虽然这两种化学方案在高NOx条件下表现相似，但它们在UMBS的低NOx水平下发散。我们确定过氧自由基和烷基硝酸盐化学差异的主要原因，强调这种化学在了解生物源挥发性有机化合物（bVOCs）的建模和测量社区的命运的重要性。
Biosphere-atmosphere interactions play a critical role in governing atmospheric composition, mediating the concentrations of key species such as ozone and aerosol, thereby influencing air quality and climate. The exchange of reactive trace gases and their oxidation products (both gas and particle phase) is of particular importance in this process. The FORCAsT (FORest Canopy Atmosphere Transfer) 1-D model is developed to study the emission, deposition, chemistry and transport of volatile organic compounds (VOCs) and their oxidation products in the atmosphere within and above the forest canopy. We include an equilibrium partitioning scheme, making FORCAsT one of the few canopy models currently capable of simulating the formation of secondary organic aerosols (SOAs) from VOC oxidation in a forest environment. We evaluate the capability of FORCAsT to reproduce observed concentrations of key gas-phase species and report modeled SOA concentrations within and above a mixed forest at the University of Michigan Biological Station (UMBS) during the Community Atmosphere-Biosphere Interactions Experiment (CABINEX) field campaign in the summer of 2009. We examine the impact of two different gas-phase chemical mechanisms on modelled concentrations of short-lived primary emissions, such as isoprene and monoterpenes, and their oxidation products. While the two chemistry schemes perform similarly under high-NOx conditions, they diverge at the low levels of NOx at UMBS. We identify peroxy radical and alkyl nitrate chemistry as the key causes of the differences, highlighting the importance of this chemistry in understanding the fate of biogenic VOCs (bVOCs) for both the modelling and measurement communities.