Export of Ozone and Precursors from Europe and Impacts on Air Quality, Climate and Ecosystems

该项目将量化控制欧洲污染出口的过程对空气质量、气候和生态系统的影响。这些过程目前缺乏观测约束，我们的理解很大程度上是基于模型模拟。我们将对受广泛的飞机和卫星观测限制的欧洲污染出口进行首批研究，并量化空气质量和气候影响。我们还将量化来自欧洲的臭氧污染在减少欧洲和西伯利亚森林的二氧化碳吸收方面所起的作用，因为它对植被造成有害影响。这将与欧洲臭氧作为温室气体对气候的直接影响进行比较。这也将能够量化由于臭氧限制对生物圈的碳吸收而导致的二氧化碳减排有效性的减少，这是政策制定者和政府迫切关心的问题。臭氧是低层大气中的一种污染物，不是直接排放的，而是在高温燃料燃烧(主要是机动车辆、发电厂、生物质燃烧)排放的氮氧化物和来自人造和自然来源的挥发性有机化合物发生阳光驱动的化学反应后在大气中形成的。臭氧是一种强氧化剂，也是低层大气中的温室气体，其浓度自前工业时代以来已显著增加。它不仅危害人类健康，还会破坏植被。这导致作物产量大幅下降，也降低了植被从大气中吸收二氧化碳的能力--这意味着这可能会导致进一步的“间接”温室效应。各主要大陆的污染物输出受到从表层边界层到上方大尺度自由对流层的污染物转移的控制，在那里可以输送超过1000千米。在北美和亚洲地区，蓝带的这种“喷发”很大程度上是由与低气压天气系统有关的锋面控制的，而在中欧地区，这种情况要少得多。人们对控制欧洲污染出口的过程知之甚少，而在欧洲下游地区(主要是北极、西伯利亚和地中海盆地)缺乏观测，加剧了我们的理解不足。我们的方法将是利用北极和西伯利亚上空的飞机实验、卫星和数值模型的新观测，来量化动态和化学过程在控制欧洲臭氧污染出口方面的作用。我们将调查这些过程如何决定空气质量和欧洲臭氧前体排放对气候的影响。此外，我们将确定人为和自然过程如何相互作用来影响这些过程，并量化欧洲臭氧污染对欧洲和西伯利亚植被吸收二氧化碳的影响。我们将最终量化这些过程在未来气候(2050年)下可能发生的变化。

This project will quantify the impacts of processes that control export of pollution from Europe on air quality, climate and ecosystems. These processes currently lack observational constraint, and our understanding is largely based on model simulations. We will conduct the first studies of European pollution export constrained by extensive aircraft and satellite observations, and quantify air quality and climate impacts. We will also quantify the role of ozone pollution from Europe in reducing CO2 uptake to European and Siberian forest, due to its harmful effects on vegetation. This will be compared with the direct climate impact of European ozone as a greenhouse gas. This will also allow quantification of a reduction in the effectiveness of CO2 emission cuts due to ozone limitation of carbon uptake to the biosphere, which is of urgent interest to policy makers and governments. Ozone is a pollutant in the lower atmosphere, which is not emitted directly, but is formed in the atmosphere by sunlight-driven chemical reactions acting on nitrogen oxides emitted from high-temperature fuel combustion (primarily motor vehicles, power plants, biomass burning) and volatile organic compounds, emitted from both man-made and natural sources. Ozone is a strong oxidant and a greenhouse gas in the lower atmosphere, and its concentrations have increased markedly since pre-industrial times. It is harmful to human health, and also damages vegetation. This leads to substantial reductions in crop yields, and also results in a reduction in the ability of vegetation to take up CO2 from the atmosphere - meaning it may result in further 'indirect' greenhouse warming. Export of pollution from the major continents in controlled by transfer of pollutants from the surface boundary layer (BL) to the overlying large-scale free troposphere (FT), where it can be transported over 1000s km. Over North America and Asia this 'venting' of the BL is controlled largely by fronts associated with low-pressure weather systems, however over central Europe these are much less frequent. Processes controlling European pollution export are much less well understood, and our lack of understanding is exacerbated by a lack of observations in regions downstream from Europe (mainly Arctic, Siberia and over the Mediterranean basin). Our approach will be to use new observations from aircraft experiments over the Arctic and Siberia, satellites and numerical models to quantify the roles of dynamic and chemical processes in controlling ozone pollution export from Europe. We will investigate how these processes determine the air quality and climate impacts of European ozone precursor emissions. In addition, we will determine how anthropogenic and natural processes interact to affect these processes, and quantify the impact of European ozone pollution on CO2 uptake to European and Siberian vegetation. We will finally quantify how these processes may change under future climate (year 2050).