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CLEARFOGG - Checking Layers of the Earths AtmospheRe For halogenated Ozone-depleting and Greenhouse Gases

CLEARFOGG - 检查地球大气层中是否存在卤化臭氧消耗气体和温室气体

基本信息

批准号：
NE/F015585/1
负责人：
Johannes Laube
金额：
$ 31.82万
依托单位：
University of East Anglia
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FF015585%2F1
关键词：
CLEARFOGG Checking Layers Earths AtmospheRe

项目摘要

To current knowledge the atmosphere contains a number of trace gases with concentrations below one part per billion. In contrast to their low concentrations these gases can have large environmental effects. Notably halocarbons are known to be very effective in global warming. For instance, in 2005 the two halocarbons CFC-11 and CFC-12 alone contributed about 14% of the effect of CO2 to the anthropogenic greenhouse effect, while CO2 is about 500,000 times more abundant (IPCC, 2007). Although most of the CFCs are decreasing in the atmosphere due to regulation by the Montreal Protocol their fluorinated substitutes also have high global warming potentials and are increasing quickly. In addition, halocarbons can enhance the destruction of ozone in the stratosphere. This occurs if chlorine or bromine is released from these molecules. In particular bromine is a very effective ozone 'killer' and the object of an ongoing scientific debate. The known organic bromine compounds do not provide enough bromine to account for the observed inorganic bromine in the stratosphere. Only a limited number of known halocarbons are continuously monitored worldwide and at times new ones are identified. There are strong indications for other fluorinated, chlorinated and brominated substances to be present in the troposphere and stratosphere. The aim of the project is to perform a systematic screening of various 'layers' in the Earth's atmosphere (boundary layer, free troposphere, tropical tropopause layer and stratosphere) for unknown halocarbons. After establishing a capable analytical system, the search for substances will start with samples from clean-air ground-based stations around the globe, then proceeding with aircraft observations in the upper troposphere/lower stratosphere and finally with balloon samples from the stratosphere. For the detected novel substances the radiative forcing and atmospheric lifetimes will be estimated in order to calculate their global warming potentials. If necessary for this purpose new infrared cross section measurements will be conducted, and radiative transfer modelling carried out. Archived air samples from remote observatories and firn air samples from deep polar snow dating back about 50 years will provide access to long term time trends. Also the influence of the new halocarbons on stratospheric ozone depletion will be determined. Not only will this search for previously unknown gases be undertaken, but also, importantly, extensive measurements will be made of the global distribution of those gases of radiative or stratospheric importance for which very few measurements presently exist; for example short-lived brominated, chlorinated and iodinated organic gases of stratospheric significance. The project will be carried at the University of East Anglia which has has extensive experience and expertise in this area.

据目前所知，大气中含有一些浓度低于十亿分之一的微量气体。与它们的低浓度相比，这些气体可能会对环境产生很大的影响。值得注意的是，众所周知，卤素在全球变暖中非常有效。例如，2005年，仅两种卤代烃CFC-11和CFC-12就贡献了大约14%的二氧化碳对人为温室效应的影响，而二氧化碳的丰度大约是前者的500,000倍(气专委，2007年)。尽管由于《蒙特利尔议定书》的管制，大气中的大多数氯氟化碳正在减少，但它们的氟化替代品也具有很高的全球变暖潜力，并且正在迅速增加。此外，卤代烃还可以加强对平流层臭氧的破坏。如果氯或溴从这些分子中释放出来，就会发生这种情况。特别值得一提的是，溴是一种非常有效的臭氧‘杀手’，也是一个正在进行的科学辩论的对象。已知的有机溴化合物不能提供足够的溴来解释平流层中观察到的无机溴。全世界只对数量有限的已知卤化碳进行持续监测，有时还会发现新的卤化碳。有强烈的迹象表明，对流层和平流层中存在其他氟化、氯化和溴化物质。该项目的目的是对地球大气层中的各种“层”(边界层、自由对流层、热带对流层顶层和平流层)进行系统的筛选，以寻找未知的卤代烃。在建立了一个有能力的分析系统后，将从全球各地清洁空气地面站的样本开始搜索物质，然后在对流层上层/平流层下层进行飞机观测，最后从平流层气球样本开始。对于探测到的新物质，将估算辐射强迫和大气寿命，以便计算它们的全球变暖潜力。如有必要，将进行新的红外截面测量，并建立辐射传输模型。来自偏远天文台的存档空气样本和来自大约50年前极地深雪的降雪空气样本将提供长期的时间趋势。此外，还将确定新的卤代烃对平流层臭氧消耗的影响。不仅将寻找以前未知的气体，而且重要的是，将广泛测量那些具有辐射或平流层意义的气体的全球分布，目前对这些气体的测量很少；例如，具有平流层意义的短暂的溴化、氯化和碘化有机气体。该项目将在东英吉利大学进行，该大学在这一领域拥有丰富的经验和专业知识。