The Role of Short-lived Species in the Tropical Atmosphere

卤素是大气化学的重要组成部分，影响平流层和对流层的臭氧浓度。目前，平流层中寿命极短的卤化碳（VSLH）的供应是平流层溴预算的一个主要不确定因素，VSLH提供了高达20%的溴总负荷。未来平流层的供应可能会受到与气候有关的变化的影响，这些变化是由于海洋表面温度和对流的增加而引起的。VSLH排放也可以在确定O3浓度方面发挥很大作用，因为高BrO水平可能导致边界层和自由对流层中O3的耗尽。一个显着改善的海洋，化学和气候因素影响VLH排放和大气浓度的理解，需要预测其重要性，在未来几十年的气候变化。热带地区面积大，对流强烈，海洋生产力高，因此至关重要。在热带太平洋和大西洋观测到了高浓度的CHBr 3、CH 2Br 2和其他VLH，这为原始大气中排放热点的重要性提供了证据。根据最近授予的NERC资助（本人是主要研究者），将于2008-2012年在西太平洋测量VSLI的大气浓度。这些时间序列将形成该地区VSLI的独特记录，因为它们是连续的和高度时间分辨率的。测量数据的收集和解释提供了一个极好的机会，使我们对科学问题的理解取得真实的突破，包括卤素在全球氧化能力中的作用，以及碘碳在热带这一地区海洋边界层气溶胶和云的产生中的作用。我将扩大我的研究兴趣，在测量VLH提供更多的知识和了解如何短命的卤烃和碳氢化合物影响热带对流层和平流层。新的连续测量将与其他测量一起解释，主要是在加州大学欧文分校收集的频率较低但20年的记录。将卤化碳数据与气象和当地海洋记录结合起来进行解释，将有助于了解厄尔尼诺和马登朱利安振荡等气候特征的影响。现有和新数据的这些分析将用于设计使用NCAS/Met Office UKCA模型的模型研究。数据分析和解释将扩大到包括现有台站（梅斯黑德、佛得角、韦伯恩以及AGAGE和NOAA网络中的台站）和热带活动（如PEM系列和OP 3）的测量结果。在这里开发的测量系统具有强大的，自主的仪器在远程站点运行，最小的人为干预有很大的潜力被扩展到包括其他仪器基于相同的理念，我将通过开发和部署其他强大的仪器包自主使用扩展的测量。从大气的角度来看，西太平洋在未来几十年将是迷人的。由于自然栖息地的变化和工业化程度的提高，VSLI和碳氢化合物的排放可能会发生重大变化。该区域的化学混合物受到太平洋上空原始空气的强烈影响，将以目前无法预测的方式演变，排放、化学、气象和海洋条件都可能发生重大变化。总的来说，我将建立一个世界领先的项目，解释测量结果，以了解该地区和全球大气中的光环和碳氢化合物的作用。这种解释性专门知识一旦发展起来，就可用于处理范围更广的大气变化问题。

The halogens are vital components in the chemistry of the atmosphere, influencing ozone concentrations in the stratosphere and the troposphere. Currently, the supply of very short-lived halocarbons (VSLH) to the stratosphere is a major uncertainty in the stratospheric bromine budget, with VSLH providing up to 20% of the total bromine loading. The future supply to the stratosphere will likely be affected by climate-related changes in the emissions of VSLH arising from increases in sea surface temperatures and convection. VSLH emissions can also play a large role in determining O3 concentrations as high BrO levels could lead to depletion of O3 in the boundary layer and free troposphere. A significantly improved understanding of the marine, chemical and climatic factors affecting VSLH emission and atmospheric concentration is required to predict their importance as climate changes in the coming decades. The tropics with its large area, regions of convective intensity and highly productive oceans is critical. High values of CHBr3, CH2Br2 and other VSLH have been observed in the tropical Pacific and Atlantic oceans, providing evidence for the importance of emission hotspots in otherwise pristine atmospheres. Measurements of atmospheric concentrations of VSLH in the Western Pacific will be made from 2008-2012 under a recently awarded NERC grant on which I am the Principal Investigator. These time series will form a unique record of VSLH in this region, as they are continuous and highly time-resolved. The collection and interpretation of the measurements provide an excellent opportunity to make real breakthroughs in our understanding of scientific issues including the role of halogens in the global oxidative capacity and the role of iodocarbons in the production of aerosols and clouds in the marine boundary layer in this region of the tropics. I will broaden my research interests in the measurement of VSLH to provide increased knowledge and understanding of how short-lived halocarbons and hydrocarbons influence the tropical troposphere and stratosphere. The new, continuous measurements will be interpreted together with other measurements, principally the less frequent but 20 year record collected at the Univ Calif Irvine. Joint interpretation of the halocarbon data with meteorological and local marine records will enable the influence of climatic features such as El Nino and the Madden Julian Oscillation to be understood. These analyses of existing and new data will be used to design model studies using the NCAS/Met Office UKCA model. Data analysis and interpretation will be extended to include measurements from existing stations (Mace Head, Cape Verde, Weyborne and those in the AGAGE and NOAA networks) and from tropical campaigns such as the PEM series and OP3. The measurement system developed here with robust, autonomous instruments operating at remote sites with minimal human intervention has great potential to be extended to include other instruments based on the same philosophy and I will extend the measurements made by developing and deploying other robust instrument packages for autonomous use. From an atmospheric perspective, the West Pacific will be fascinating over the coming decades. Emissions of VSLH and hydrocarbons are likely to change significantly as a result of changes to natural habitats and increased industrialisation. The chemical mix in this region, strongly affected as it is by the pristine air over the Pacific Ocean itself, will evolve in a currently unpredictable way, with emissions, chemistry, meteorology and oceanic conditions all likely to change significantly. Overall, I will establish a world-leading programme interpreting measurements to understand the role of halo- and hydrocarbons in this region and in the global atmosphere. Once developed, this interpretative expertise can be used to address a much broader range of atmospheric change issues.