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成分组成的。例如，大气不仅受到现场发生的过程的控制，而且还受到来自陆地和海洋表面的能量通量和各种化学物质的控制。同样，大气成分也取决于地球表面的沉积。此外，这些过程都可能随气候状态而变化。直到最近，详细的化学方案才被纳入最好的气候模型。陆地表面过程（排放、沉积等）与化学/气候系统之间的耦合已被引入数值模式，尽管有所简化。然而，后一种相互作用可能对构成和气候非常重要。在英国气象局和NERC大气科学中心（NCAS）已经开展的一项倡议的基础上，现在正是英国在NERC的QUEST项目中开展一项重大倡议的时候，该倡议旨在研究地表过程对大气氧化能力和气溶胶负荷的作用，该倡议旨在开发一种新的社区模型，UKCA，以研究气候与成分（气相成分和气溶胶）之间的相互作用。本提案解决了这一任务。我们的建议汇集了英国的相关专业知识，重点关注四个方面。这些是(1)开发和测试化学和气溶胶方案，将其纳入气候模式；(2)开发和测试一系列方案，以描述（尽可能互动地）反应性微量气体的地表排放；(3)开发和测试新的地表沉积方案；(4)在气候模式中实施这些方案，该模式将用于研究模式系统在最近的过去和不久的将来与气候相关的变率。这将使不断变化的气候和地表排放之间的相互作用与在该系统内发生的反馈的完整描述成为可能。气候模式输出的变化将直接影响排放，因为温度、土壤湿度和光照强度的变化对生物源性挥发性有机化合物（VOCs）的排放速率有直接影响。这些排放（例如，高度依赖温度的异戊二烯排放）可以影响氧化能力，从而影响对流层OH和包括臭氧在内的活性温室气体的浓度，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水平的升高也可能改变挥发性有机化合物的排放率。我们的研究将允许在涵盖上个世纪和下个世纪的研究中评估这些化学/气候反馈过程。

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.