Collaborative Research: Impact of Snow Photochemistry on Atmospheric Radical Concentrations at Summit, Greenland

合作研究：格陵兰岛山顶雪光化学对大气自由基浓度的影响

• 批准号: 0220763
• 负责人: Barry Lefer
• 金额: $ 20.65万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0220763&HistoricalAwards=false
• 关键词: Collaborative; Research; Impact; Snow; Photochemistry

Lefer0220763In the past few years there has been an explosion of scientific interest in the chemical processing occurring in sunlit snow. Rather than simply acting as a passive sink for the products of tropospheric reactions, the snowpack has been shown to be one of the most photochemically active, and strongly oxidizing, regions of the entire troposphere. The group of investigators assembled for this proposal has played a central role in this revolution in our thinking about the role of the snowpack in atmospheric chemistry. One key finding has been that photolysis of snow chromophores initiates the release of a number of important trace gases. Initial modeling suggests that photolysis of a number of these gases (HCHO, HOOH, CH3CHO and HONO) results in an enormous production of HOx (i.e., OH and HO2), which in turn causes a large enhancement of these radicals in the snowpack and in the air just above the snow. Because oxidation by OH is the main sink for many tropospheric gases, including some of those important for climate change and stratospheric O3 depletion, this enhancement in HOx might significantly perturb tropospheric chemistry. Snowpack chemistry likely also modifies the chemical records of atmospheric composition ultimately preserved in glacial ice. While recent work has shown that photochemical and physical processes in the snowpack can impact the chemistry and composition of both the atmosphere and snowpack, these processes are, in general, poorly understood. This is especially true for the processes that produce and consume OH and HO2. The research will elucidate the processes that produce and consume OH and HO2 radicals within and above sunlit snow over a wide range of environmental conditions, thereby improving our understanding of fast photochemistry within this unique environment.

Lefer0220763在过去几年中，在阳光降雪中发生的化学加工中引起了科学兴趣。 Snekpack并非简单地充当对流层反应产物的被动水槽，而是整个对流层的光化学活性最高，强烈氧化的区域之一。为此提案组装的一组调查人员在我们对Snowpack在大气化学中的作用的思考中在这项革命中发挥了核心作用。一个关键发现是，雪发色团的光解会引发许多重要的痕量气体的释放。最初的建模表明，这些气体的光解（HCHO，HOOH，CH3CHO和HONO）导致HOX产生巨大的HOX（即OH和HO2），进而导致这些自由基在雪堆中和空气中的大量增强。因为OH的氧化是许多对流层气体的主要水槽，包括其中一些对于气候变化和平流层O3耗竭很重要，因此HOX的这种增强可能会显着扰乱对流层化学。 Snowpack化学可能还会改变最终保存在冰川冰中的大气组成的化学记录。虽然最近的工作表明，积雪中的光化学和物理过程会影响大气和积雪的化学和组成，但通常对这些过程的理解很少。对于生产和消费OH和HO2的过程尤其如此。这项研究将阐明在广泛的环境条件下在阳光下降雪内外产生和消耗OH和HO2激进分子的过程，从而在这种独特的环境中提高我们对快速光化学的理解。