Modelling of atmospheric oxidants and aerosols: deposition, emission and chemical transformation / QUEST

地球系统是由大量相互作用的组成部分组成的。例如，大气层不仅受到原地发生的过程的控制，而且还受到陆地和海洋表面的能量通量和各种化学物质的控制。同样，大气成分也取决于沉积到地球表面。此外，这些过程都可能随着气候状态而变化。直到最近，详细的化学方案才被纳入最好的气候模型。陆面过程（排放、沉积等）之间的耦合化学/气候系统已被引入数值模式，尽管有些简化。然而，后者的相互作用可能对成分和气候非常重要。现在是时候在NERC的QUEST计划中进行一项重大的英国倡议，研究表面过程对大气氧化能力和气溶胶负荷的作用，建立在气象局和NERC大气科学中心（NCAS）之间已经进行的一项倡议的基础上，开发一个新的社区模型UKCA，研究气候和成分（气相成分和气溶胶）之间的相互作用。本提案涉及这一任务。我们的建议汇集了英国的相关专业知识，有四个主要重点。这些是（1）发展和测试化学和气溶胶方案，包括在一个气候模式，（2）发展和测试一系列方案，以描述（在可能的情况下相互作用）活性痕量气体的表面排放，（3）新的表面沉积方案的开发和测试，以及（4）将这些方案应用到气候模式中，以研究模式系统在最近的过去和不久的将来与气候有关的变率。这将使不断变化的气候和地面排放之间的相互作用，充分说明这个系统内发生的反馈。气候模式输出的变化将直接影响排放量，因为温度、土壤湿度和光照强度的变化对生物挥发性有机化合物的排放率有直接影响。这些排放物（例如，强烈依赖于温度的异戊二烯排放物）可以影响氧化能力，从而影响对流层OH，从而影响包括臭氧在内的反应性温室气体的浓度，从而完成反馈回路。二阶效应也可能很重要，例如，土壤湿度的变化或地面臭氧的升高也可能改变挥发性有机化合物的排放率。我们的研究将使这些化学/气候反馈过程进行评估的研究，涵盖了上个世纪和未来世纪。

The earth system is comprised of a large number of interacting components. For example, the atmosphere is controlled not just by processes occurring in situ but also by fluxes of energy and a variety of chemical species from the land and ocean surfaces. Similarly, atmospheric composition also depends on deposition to the earth surface. Furthermore, these processes are all likely to change with the climate state. It is only recently that detailed chemical schemes have been included in the best climate models. Coupling between land surface processes (emissions, deposition, etc.) and the chemistry/climate system has been introduced into numerical models, albeit somewhat simplified. These latter interactions could however be very important for composition and climate. The time in now right for a major UK initiative within NERC's QUEST programme, to study the role of surface processes on atmospheric oxidizing capacity and aerosol loading, building on an initiative already underway between the Met Office and the NERC Centres for Atmospheric Science (NCAS) to develop a new community model, UKCA, to study the interaction between climate and composition (gas phase composition and aerosols). This proposal addresses that task. Our proposal brings together relevant UK expertise with four main foci. These are (1) the development and testing of chemistry and aerosol schemes to include in a climate model, (2) the development and testing of a range of schemes to describe (interactively wherever possible) surface emissions of reactive trace gases, (3) the development and testing of new surface deposition schemes, and (4) implementation of these schemes into the climate model which will be used to look at climate-related variability of the model system for the immediate past and the near future. This will allow the interaction between changing climate and surface emissions with full description of the feedbacks occurring within this system. Changes in the output of the climate model will affect emissions directly, as changes in temperature, soil moisture and light intensity have direct effects on the emission rates of biogenic volatile organic compounds (VOCs). These emissions (for example, the strongly temperature-dependent isoprene emissions) can affect oxidizing capacity, and hence tropospheric OH and so the concentration of reactive greenhouse gases, including ozone, thereby completing the feedback loop. Second-order effects may also be important, for example, changes insoil moisture or elevated ground level ozone may also alter VOC emission rates. Our study will allow these chemistry/climate feedback processes to be assessed in studies covering the last century and the coming century.