Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period
Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period
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DOI：
10.5194/acp-11-3173-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Zhang, Q.
中科院分区：
文献类型：
--
作者：
Huang, M.;Carmichael, G. R.;Zhang, Q.
在南海岸（SC）和加州（CA）的其他地区，长期高的地面臭氧（O-3）水平和不断增加的硫氧化物（SOx = SO2+ SO 4）环境浓度受到本地排放和远程传输的影响。本文利用STEM大气化学模式进行了多尺度示踪、全化学和伴随模式模拟，以评估2008年ARCTAS-CARB试验期间本地排放源对SC O-3的贡献，并评估了输送硫和本地排放对SC O-3的影响。敏感性模拟量化贡献的生物和火灾排放SC O-3水平。加州生物源和火灾排放贡献3-4 ppb的近地表O-3超过SC，与更大的贡献，在CA的其他地区。在6月22日开始的亚洲远程传输事件期间，在6公里以上观察到高SOx水平（高达0.7 ppb的SO2和1.3 ppb的SO 4），但它们并没有影响CA地面空气质量。在1-4公里处观测到的SOx升高估计会使SC上空的表面SOx增加0.25 ppb（上限），类似于6月24日。在飞行周期间，SC上空的近地面SOx水平主要归因于本地排放。比较了加州空气资源委员会（CARB）和美国环境保护署（EPA）的两个人为SOx排放清单（EI），并将其应用于60 km和12 km化学传输模拟，将结果与观测结果进行了比较。CARB EI比EPA的国家排放清单（NEI）有所改进，但通常低估了表面SC SOx约2倍。伴随的敏感性分析表明，SO2水平在00：00 UTC（17：00当地时间）在6个SC表面站点的影响，前一天的海洋排放，陆地排放附近的城市地区，并从北方通过陆地和海洋地区输送SO2。总体而言，海洋排放贡献了10-70%的SO2和20-60%的陆地和大部分陆地地区的细SO 4，随着距离海岸的内陆距离的增加，贡献率逐渐降低。海洋排放也改变了光化学环境，将沿海SC的O-3生产转移到VOC限制的条件下。这表明船舶排放控制在减少SC中细颗粒物和O-3浓度方面具有重要作用。
Chronic high surface ozone (O-3) levels and the increasing sulfur oxides (SOx = SO2+SO4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O-3 and to evaluate the impacts of transported sulfur and local emissions on the SC sulfur budget-during the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O-3 levels. California biogenic and fire emissions contribute 3-4 ppb to near-surface O-3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SOx levels (up to similar to 0.7 ppb of SO2 and similar to 1.3 ppb of SO4) is observed above similar to 6 km, but they did not affect CA surface air quality. The elevated SOx observed at 1-4 km is estimated to enhance surface SOx over SC by similar to 0.25 ppb (upper limit) on similar to 24 June. The near-surface SOx levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SOx emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared with observations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SOx by about a factor of two. Adjoint sensitivity analysis indicated that SO2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10-70% of SO2 and 20-60% fine SO4 on-shore and over the most terrestrial areas, with contributions decreasing with inland distance from the coast. Maritime emissions also modify the photochemical environment, shifting O-3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O-3 concentrations in SC.