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首页> 外文期刊>Atmospheric Chemistry and Physics Discussions >Glyoxal yield from isoprene oxidation and relation to formaldehyde: chemical mechanism, constraints from SENEX aircraft observations, and interpretation of OMI satellite data
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Glyoxal yield from isoprene oxidation and relation to formaldehyde: chemical mechanism, constraints from SENEX aircraft observations, and interpretation of OMI satellite data

机译：异戊二烯氧化产生的乙二醛产量及其与甲醛的关系：化学机理，SENEX飞机观测的限制以及OMI卫星数据的解释

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pstrongAbstract./strong Glyoxal (CHOCHO) is produced in the atmosphere by the oxidation of volatile organic compounds (VOCs). Like formaldehyde (HCHO), another VOC oxidation product, it is measurable from space by solar backscatter. Isoprene emitted by vegetation is the dominant source of CHOCHO and HCHO in most of the world. We use aircraft observations of CHOCHO and HCHO from the SENEX campaign over the southeast US in summer??2013 to better understand the CHOCHO time-dependent yield from isoprene oxidation, its dependence on nitrogen oxides (NOsubix/i/subspan class="thinspace"/spana??a??a??span class="thinspace"/spanNOspan class="thinspace"/span+span class="thinspace"/spanNOsub2/sub), the behavior of the CHOCHO–HCHO relationship, the quality of OMI CHOCHO satellite observations, and the implications for using CHOCHO observations from space as constraints on isoprene emissions. We simulate the SENEX and OMI observations with the Goddard Earth Observing System chemical transport model (GEOS-Chem) featuring a new chemical mechanism for CHOCHO formation from isoprene. The mechanism includes prompt CHOCHO formation under low-NOsubix/i/sub conditions following the isomerization of the isoprene peroxy radical (ISOPOsub2/sub). The SENEX observations provide support for this prompt CHOCHO formation pathway, and are generally consistent with the GEOS-Chem mechanism. Boundary layer CHOCHO and HCHO are strongly correlated in the observations and the model, with some departure under low-NOsubix/i/sub conditions due to prompt CHOCHO formation. SENEX vertical profiles indicate a free-tropospheric CHOCHO background that is absent from the model. The OMI CHOCHO data provide some support for this free-tropospheric background and show southeast US enhancements consistent with the isoprene source but a factor of 2 too low. Part of this OMI bias is due to excessive surface reflectivities assumed in the retrieval. The OMI CHOCHO and HCHO seasonal data over the southeast US are tightly correlated and provide redundant proxies of isoprene emissions. Higher temporal resolution in future geostationary satellite observations may enable detection of the prompt CHOCHO production under low-NOsubix/i/sub conditions apparent in the SENEX data./p.
机译：> >摘要。乙二醛（CHOCHO）是在大气中通过挥发性有机化合物（VOC）的氧化而产生的。像另一种VOC氧化产物甲醛（HCHO）一样，它可以通过太阳后向散射从太空中测量出来。植被释放的异戊二烯是世界上大部分地区CHOCHO和HCHO的主要来源。我们利用2013年夏季美国东南部SENEX战役中对CHOCHO和HCHO的飞机观测结果，更好地了解了异戊二烯氧化的CHOCHO时间依赖性产量，其依赖于氮氧化物（NO x class =“ thinspace”> a ?? a ?? a ?? class =“ thinspace”> NO class =“ thinspace”> + class =“ thinspace”> NO 2 ），CHOCHO＆ndash; HCHO关系的行为，OMI CHOCHO卫星观测的质量以及使用CHOCHO观测的含义限制了异戊二烯的排放。我们使用戈达德地球观测系统化学传输模型（GEOS-Chem）模拟SENEX和OMI观测，该模型具有从异戊二烯形成CHOCHO的新化学机理。该机制包括在异戊二烯过氧自由基（ISOPO 2 ）异构化后，在低NO x 条件下迅速形成CHOCHO。 SENEX观测结果为这种迅速的CHOCHO形成途径提供了支持，并且通常与GEOS-Chem机制一致。边界层CHOCHO和HCHO在观测和模型中密切相关，在低NO x 条件下由于迅速形成CHOCHO而有一些偏离。 SENEX垂直剖面表示模型中没有对流层自由CHOCHO背景。 OMI CHOCHO数据对此自由对流层背景提供了一些支持，并显示美国东南部的增强与异戊二烯来源一致，但因数2太低。这种OMI偏差的部分原因是在取回过程中假定了过多的表面反射率。美国东南部的OMI CHOCHO和HCHO季节数据紧密相关，并提供了异戊二烯排放的冗余代理。在未来的对地静止卫星观测中，更高的时间分辨率可能可以检测到在SENEX数据中出现的低NO x 条件下迅速产生的CHOCHO。。

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