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首页> 外文期刊>Atmospheric chemistry and physics >Aircraft measurements over Europe of an air pollution plume from Southeast Asia – aerosol and chemical characterization
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Aircraft measurements over Europe of an air pollution plume from Southeast Asia – aerosol and chemical characterization

机译：欧洲对来自东南亚的空气污染烟流进行的飞机测量-气溶胶和化学特征

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An air pollution plume from Southern and Eastern Asia, including regions inIndia and China, was predicted by the FLEXPART particle dispersion model toarrive in the upper troposphere over Europe on 24–25 March 2006. According tothe model, the plume was exported from Southeast Asia six days earlier,transported into the upper troposphere by a warm conveyor belt, and travelledto Europe in a fast zonal flow. This is confirmed by the retrievals of carbonmonoxide (CO) from AIRS satellite measurements, which are in excellentagreement with the model results over the entire transport history. Theresearch aircraft DLR Falcon was sent into this plume west of Spain on 24March and over Southern Europe on 25 March. On both days, the pollution plumewas found close to the predicted locations and, thus, the measurements takenallowed the first detailed characterization of the aerosol content andchemical composition of an anthropogenic pollution plume after a nearlyhemispheric transport event. The mixing ratios of CO, reactive nitrogen(NOy) and ozone (O3) measured in the Asian plume were all clearlyelevated over a background that was itself likely elevated by Asianemissions: CO by 17–34 ppbv on average (maximum 60 ppbv) and O3 by2–9 ppbv (maximum 22 ppbv). Positive correlations existed between thesespecies, and a ΔO3/ΔCO slope of 0.25 shows that ozone wasformed in this plume, albeit with moderate efficiency. Nucleation mode andAitken particles were suppressed in the Asian plume, whereas accumulationmode aerosols were strongly elevated and correlated with CO. The suppressionof the nucleation mode was likely due to the large pre-existing aerosolsurface of the transported larger particles. Super-micron particles, likelydesert dust, were found in part of the Asian pollution plume and also insurrounding cleaner air. The aerosol light absorption coefficient wasenhanced in the plume (average values for individual plume encounters0.25–0.70 Mm−1), as was the fraction of non-volatile Aitken particles.This indicates that black carbon (BC) was an important aerosol component.During the flight on 25 March, which took place on the rear of a troughlocated over Europe, a mixture of Asian pollution and stratospheric air wasfound. Asian pollution was mixing into the lower stratosphere, andstratospheric air was mixing into the pollution plume in the troposphere.Turbulence was encountered by the aircraft in the mixing regions, where thethermal stability was low and Richardson numbers were below 0.2. The resultof the mixing can clearly be seen in the trace gas data, which are followingmixing lines in correlation plots. This mixing with stratospheric air islikely very typical of Asian air pollution, which is often lifted to theupper troposphere and, thus, transported in the vicinity of stratosphericair.
机译：FLEXPART颗粒扩散模型预测，2006年3月24日至25日，来自南亚和东亚（包括印度和中国地区）的空气污染羽流将抵达欧洲对流层上方。根据该模型，该羽流从东南亚六个国家出口。天前，它被一条温暖的输送带运入对流层上层，并以快速的纬向流向欧洲旅行。从AIRS卫星测量中检索到的一氧化碳（CO）证实了这一点，这与整个运输历史上的模型结果都非常吻合。 Theresearch飞机DLR Falcon于3月24日被送入西班牙以西的这个羽流中，并于3月25日被送入南欧。在这两天中，发现污染羽状体接近预测位置，因此，进行了测量，从而对近半球运输事件后人为污染羽状体的气溶胶含量和化学成分进行了首次详细表征。在亚洲羽状流中测得的CO，反应性氮（NO y ）和臭氧（O 3 ）的混合比均在可能由亚洲排放物升高的背景下明显升高：CO平均减少17–34 ppbv（最大60 ppbv），O 3 平均减少2–9 ppbv（最大22 ppbv）。这些物种之间存在正相关，ΔO 3 /ΔCO斜率为0.25，表明在该羽流中形成了臭氧，尽管效率中等。亚洲羽中的成核模式和艾特肯粒子受到抑制，而累积模式的气溶胶则强烈升高并与CO相关。成核模式的抑制很可能是由于运输的较大粒子预先存在的较大的气溶胶表面。在亚洲污染羽流的一部分中还发现了超微米颗粒，可能是沙漠尘埃，并且包围了更清洁的空气。羽中的气溶胶光吸收系数得到了增强（单个羽的平均值遇到0.25–0.70 Mm -1 ），非挥发性艾特肯粒子的分数也增加了。这表明黑碳（BC ）是重要的气溶胶成分.3月25日，在欧洲上空的一个槽后部进行的飞行中，发现了亚洲污染和平流层空气的混合物。亚洲的污染正混入低空平流层，平流层的空气正混入对流层的污染羽流。飞机在混合区遇到湍流，其热稳定性较低，理查森数低于0.2。混合的结果可以在痕量气体数据中清楚地看到，这些数据在相关图中遵循混合线。与平流层空气的这种混合可能是亚洲空气污染的非常典型的现象，它经常被抬升到对流层的上部，并因此在平流层空气附近运输。

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