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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Oxidized nitrogen and ozone production efficiencies in the springtime free troposphere over the Alps
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Oxidized nitrogen and ozone production efficiencies in the springtime free troposphere over the Alps

机译：阿尔卑斯山春季自由对流层中氮和臭氧的氧化效率

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The Free Tropospheric Experiment (FREETEX'98) was conducted at the Jungfraujoch Observatory in the Swiss Alps (3580 m above sea level) during the well-documented spring maximum in ozone. In spring the Jungfraujoch frequently lies in the free troposphere but can also be influenced by air from the planetary boundary layer. Measurements of NOx, NOy, peroxyacetylnitrate (PAN), HCHO, O-3, CO, nonmethane hydrocarbons, peroxy radicals, j((OD)-D-1),j(NO2) and a variety of other tropospheric constituents crucial to ozone photochemical cycles were made over a 1-month period. Two independent measurements of NOx NOy, and PAN showed good agreement. Average free tropospheric daytime NO levels were about 50 pptv, sufficient to sustain photochemical ozone formation. Although high mixing ratios were encountered, PAN decomposition did not contribute to NOx production during FREETEX'98. Ozone production efficiencies (EN) derived from observed Delta O-3/(NOz) ratios in Free tropospheric air were 20-30 molecules of O-3 produced per NOx molecule oxidized and agreed well with a photochemical model. A much lower ozone production efficiency of 4 was determined in a photochemically aged air mass arriving from southern Europe, in line with other. measurements and calculations in regimes containing high levels of oxidized nitrogen. Model simulations indicated that by sequestering NOx and HO2, low-temperature formation of peroxynitric acid (PNA) decreased ozone production by 20% and instantaneous ozone production efficiencies by 40%, whereas PAN formation had little effect. The model reproduced well the observed sharp transformation from ozone production to ozone destruction (defined as Delta O-3/Delta(NOz) = 0) at 20-25 pptv NO. The observed and calculated strong dependence of E-N on NOx concentration in the low-NO, regime highlights the difficulty in assigning a single O-3 production efficiency value to remote regions, where most of the CO and CH4 in the atmosphere are oxidized. [References: 49]
机译：在对臭氧层有充分记录的春季最大值期间，在瑞士阿尔卑斯山的少女峰天文台（海拔3580 m）进行了自由对流层实验（FREETEX'98）。在春季，少女峰经常位于自由对流层，但也可能受到来自行星边界层的空气的影响。 NOx，NOy，过氧乙酰硝酸盐（PAN），HCHO，O-3，CO，非甲烷烃，过氧自由基，j（（OD）-D-1），j（NO2）以及对臭氧至关重要的其他多种对流层成分的测量在1个月内进行了光化学循环。对NOx NOy和PAN的两次独立测量显示出良好的一致性。对流层白天平均NO含量约为50 pptv，足以维持光化学臭氧的形成。尽管遇到了高混合比，但PAN分解并没有促进FREETEX'98期间的NOx产生。从对流层自由空气中观察到的Delta O-3 /（NOz）比得出的臭氧生产效率（EN）为，每氧化一个NOx分子产生的20-30分子O-3分子被氧化，并与光化学模型非常吻合。从南欧到达的经过光化学老化的空气团中，臭氧的产生效率要低得多，为4。在含有高水平氧化氮的环境中进行测量和计算。模型模拟表明，通过隔离NOx和HO2，低温形成过氧硝酸（PNA）可使臭氧产生量降低20％，瞬时臭氧产生效率降低40％，而PAN形成的影响很小。该模型很好地再现了在20-25 pptv NO处观察到的从臭氧生产到臭氧破坏的急剧转变（定义为Delta O-3 / Delta（NOz）= 0）。观察到并计算出的E-N在低NO浓度下对NOx浓度的强烈依赖性，突显了难以为偏远地区分配单个O-3生产效率值的困难，在偏远地区，大气中的大多数CO和CH4被氧化。 [参考：49]

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