RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere)

现在有越来越多的重要证据表明，主要由硝酸根N3驱动的夜间化学在控制对流层组成方面发挥着重要作用。最近的发现表明，在远离地球表面的地方，存在着浓度非常高的NO3。在污染环境中，主要的汇是丰富的，但这也是它形成最快的地方，因此N3的周转时间非常快。这一行为的重要性尚不清楚，但它可能对大气化学和臭氧的形成、氧化氮的区域迁移和转化以及酸化和富营养化产生非常大的影响，还可能大大增加区域硝酸铵颗粒的负担，因为硝酸铵颗粒在气候上具有越来越重要的意义。为了正确理解和预测这些现象，需要量化控制NO3及其从大气中清除的基本化学过程；NO3化学对挥发性有机碳化学的影响和作为自由基形成和传播途径的影响；它的非均相化学及其对气溶胶负荷和组成的影响；它对区域和全球尺度上臭氧形成的影响以及它对氧化态氮大气生命周期的调节。提议了一个联合体项目，利用仪器开发、航空测量、详细过程建模以及区域和全球建模的综合方案来解决这些相互关联的问题。主要交付成果将是：a)增强FAAM飞机的仪器能力，包括对N3和N2O5的测量。B)在各种条件下全面测量夜间基团、它们的源和汇以及边界层和自由对流层中的气溶胶成分。D)对控制夜间化学过程的关键过程进行量化。E)评估夜间化学物质对区域范围的影响。F)评估夜间化学在当前和未来大气层中的全球影响。

There is now a significant and increasing body of evidence that night time chemistry, driven primarily by the nitrate radical NO3, plays a significant role in governing the composition of the troposphere. Recent findings show that very high concentrations of NO3 are present away from the Earth's surface. In polluted environments, the main sinks are abundant but this is also where its formation may be most rapid and hence the NO3 turnover time is very fast. The importance of this behaviour is not as yet clearly understood, yet it may have a very large impact on atmospheric chemistry and ozone formation, regional transport and transformation of oxidised nitrogen and hence acidification and eutrophication, and may also significantly add to the regional burden of ammonium nitrate particulate, which has increasing climatic importance. To understand and predict these phenomena correctly there is a need to quantify the basic chemical processes controlling NO3 and its removal from the atmosphere; the impact of NO3 chemistry on volatile organic carbon chemistry and as a pathway for radical formation and propagation; its heterogeneous chemistry and its impact on the aerosol burden and composition; its influence on ozone formation on regional and global scales and its mediation of the atmospheric lifecycle of oxidised nitrogen. A consortium project is proposed that addresses these coupled questions using a combined programme of instrument development, airborne measurement, detailed process modelling, and regional and global modelling. The principal deliverables will be: a) Enhancements to the instrumental capability of the FAAM aircraft to include measurements of NO3 and N2O5. b) Comprehensive measurements of night time radicals, their sources and sinks, and aerosol composition in the boundary layer and free troposphere in a range of conditions. d) Quantification of the key processes which control night-time chemical processes. e) Assessment of the impacts of night-time chemistry on regional scales. f) An assessment of the global impacts of night-time chemistry in the current and future atmospheres.