Profiling of formaldehyde, glyoxal, methylglyoxal, and CO over the Amazon: normalized excess mixing ratios and related emission factors in biomass burning plumes
Profiling of formaldehyde, glyoxal, methylglyoxal, and CO over the Amazon: normalized excess mixing ratios and related emission factors in biomass burning plumes
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DOI：
10.5194/acp-20-12363-2020
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发表时间：
2020-10
影响因子：
6.3
通讯作者：
Flora Kluge;Tilman Hüneke;M. Knecht;M. Lichtenstern;Meike K. Rotermund;H. Schlager;Ben Schreiner
中科院分区：
文献类型：
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作者：
Flora Kluge;Tilman Hüneke;M. Knecht;M. Lichtenstern;Meike K. Rotermund;H. Schlager;Ben Schreiner
摘要。我们报告了2014年秋季德国高空和远程研究飞机（HALO）在ac透顶- chuva活动期间对亚马逊盆地上空对流层甲醛（CH2O）、乙二醛（C2H2O2）、甲基乙二醛和更高的羰基（c3h4o2 *）和一氧化碳（CO）的混合率和垂直剖面的机载测量。通过对原位CO和远程测量的CH2O、C2H2O2和c3h2o2 *的联合观测，以及使用NOAA HYSPLIT（美国国家海洋大气管理局混合单粒子拉格朗日综合轨迹）的可见光图像和气团反轨迹建模，我们可以区分对背景热带空气的探测，其中测量物种的浓度来自生物源排放的挥发性有机化合物（VOCs）的氧化，主要是异戊二烯)，以及受生物质燃烧排放或玛瑙斯城市羽流影响的中度至重度污染气团的测量。对新鲜生物质燃烧羽流的12次近地表测量，推断了C2H2O2和c3h4o2 *相对于CH2O的标准化过量混合比，并与最近的研究进行了比较。乙二醛与甲醛的平均比率RGF=0.07（范围0.02-0.11）与最近的报告一致，这些报告表明RGF明显低于以前在全球化学运输模型（CTMs）中假设的RGF。在不同的观测设置中，甲基乙二醛与甲醛的平均比值RMF=0.98（范围0.09-1.50）变化显著，但即使应用校正因子2.0±0.5来考虑c3h4o2 *测量中包含的额外二羰基，总体上似乎比以前的报告所建议的要大得多（高达5倍）。利用最近报道的热带森林CH2O排放因子，我们的观察结果表明，C2H2O2的EFG排放因子=0.25（范围0.11至0.52）g kg - 1， c3h2o2的EFM = 4.7（范围0.5至8.64）g kg - 1。虽然EFG与最近的报告非常一致，但EFM（像RMF一样）比其他研究报告略大，可能是由于所研究的羽流年龄或燃料不同。我们对这些关键羰基和中间氧化产物的观测可能支持未来热带植被空气污染的光化学模拟，以及验证过去和现在对各自物种的空间观测。
Abstract. We report on airborne measurements of tropospheric mixing ratios and vertical profiles of formaldehyde ( CH2O ), glyoxal ( C2H2O2 ), methylglyoxal and higher carbonyls ( C 3 H 4 O 2 * ) (see below), and carbon monoxide ( CO ) over the Amazon Basin during the ACRIDICON-CHUVA campaign from the German High Altitude and Long-range research aircraft (HALO) in autumn 2014. The joint observation of in situ CO and remotely measured CH2O , C2H2O2 , and C 3 H 4 O 2 * , together with visible imagery and air mass back-trajectory modelling using NOAA HYSPLIT (National Oceanic Atmospheric Administration, HYbrid Single-Particle Lagrangian Integrated Trajectory), allows us to discriminate between the probing of background tropical air, in which the concentration of the measured species results from the oxidation of biogenically emitted volatile organic compounds (VOCs, mostly isoprene), and measurements of moderately to strongly polluted air masses affected by biomass burning emissions or the city plume of Manaus. For 12 near-surface measurements of fresh biomass burning plumes, normalized excess mixing ratios of C2H2O2 and C 3 H 4 O 2 * with respect to CH2O are inferred and compared to recent studies. The mean glyoxal-to-formaldehyde ratio RGF=0.07 (range 0.02–0.11) is in good agreement with recent reports which suggest RGF to be significantly lower than previously assumed in global chemical transport models (CTMs). The mean methylglyoxal-to-formaldehyde ratio RMF=0.98 (range 0.09–1.50) varies significantly during the different observational settings but overall appears to be much larger (up to a factor of 5) than previous reports suggest even when applying a correction factor of 2.0±0.5 to account for the additional dicarbonyls included in the C 3 H 4 O 2 * measurements. Using recently reported emission factors of CH2O for tropical forests, our observations suggest emission factors of EFG=0.25 (range 0.11 to 0.52) g kg−1 for C2H2O2 and EFM = 4.7 (range 0.5 to 8.64) g kg−1 for C 3 H 4 O 2 * . While EFG agrees well with recent reports, EFM is (like RMF ) slightly larger than reported in other studies, presumably due to the different plume ages or fuels studied. Our observations of these critical carbonyls and intermediate oxidation products may support future photochemical modelling of air pollution over tropical vegetation, as well as validate past and present space-borne observations of the respective species.