Characteristics of biomass burning emission sources, transport, and chemical speciation in enhanced springtime tropospheric ozone profile over Hong Kong
Characteristics of biomass burning emission sources, transport, and chemical speciation in enhanced springtime tropospheric ozone profile over Hong Kong
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DOI：
10.1029/2001jd001555
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发表时间：
2003-01-09
影响因子：
4.4
通讯作者：
Zheng, XD
中科院分区：
文献类型：
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作者：
Chan, CY;Chan, LY;Zheng, XD
香港上空的对流层臭氧（O-3）持续增强。我们研究了O-3的增强事件，并评估其与春季在香港对流层低层的O-3最大值使用6年（1993年至1999年）臭氧探空仪数据集的关系。我们确定了生物质燃烧排放的源区，并建立了增强的O-3剖面中富含O-3的空气质量的化学和传输特性，使用卫星图像，空气轨迹和微量气体数据测量的DC-8飞机在PEM-西-B实验。我们总共识别出39次O-3增强事件，其中35次事件（90%）发生在2月下旬至5月，30次事件（77%）在2.0-6.0 km高度范围内出现O-3增强。过量的O-3在O-3丰富的层中添加了额外的12%的O-3到对流层O-3柱中，并导致对流层下部的整体春季O-3最大值。前向轨迹分析显示，香港上空的富O-3气团可在10天内到达中太平洋及北美洲西岸。背空气轨迹显示，在增强的配置文件中的O-3-丰富的空气质量通过东南亚（SE）亚洲次大陆，在那里活跃的生物质燃烧发生在O-3增强期间。我们确定了包括缅甸、老挝和泰国北方的印缅地区以及包括印度北方和尼泊尔的印度-尼泊尔地区为东南亚次大陆生物质燃烧排放最活跃的两个地区。在DC-8飞机上进行的臭氧和微量气体测量显示，在东南亚热带和西太平洋副热带地区的许多地方都发现了富含O-3的气团，它们具有相似的化学特征。伴随的微量气体测量表明，O-3丰富的空气质量是丰富的生物质燃烧示踪剂，CH 3Cl，但不是一般的城市排放示踪剂。因此，我们相信香港上空春季臭氧浓度的增加，是由于来自逆风的东南亚大陆的生物质燃烧排放物所产生的光化学臭氧的输送所致。大规模的增强O-3在热带东南亚和亚热带西太平洋边缘，导致东南亚生物质燃烧活动，如这里提出的，因此是大气的重要性，值得进一步的研究工作。
Tropospheric ozone (O-3) enhancements have been continuously observed over Hong Kong. We studied the O-3 enhancement events and assessed their relation to the springtime O-3 maximum in the lower troposphere over Hong Kong using a 6-year (1993 to 1999) ozonesonde data set. We identified the source regions of biomass burning emission, and established the chemical and transport characteristics of O-3-rich air masses in the enhanced O-3 profiles using satellite imagery, air trajectory and trace gas data measured on board the DC-8 aircraft during the PEM-West-B experiment. We identified a total of 39 O-3 enhancement events, among which 35 events (90%) occurred from late February to May and 30 events (77%) had O-3 enhancement within the 2.0-6.0 km altitude. The excess O-3 in the O-3-rich layers adds an additional 12% of O-3 into the tropospheric O-3 column and results in an overall springtime O-3 maximum in the lower troposphere. Forward trajectory analysis suggests that the O-3-rich air masses over Hong Kong can reach central Pacific and the western coast of North America within 10 days. Back air trajectories show that the O-3-rich air masses in the enhanced profiles pass over the Southeast (SE) Asia subcontinent, where active biomass burning occurs in the O-3 enhancement period. We identified the Indo-Burma region containing Burma, Laos and northern Thailand, and the Indian-Nepal region containing northern India and Nepal as the two most active regions of biomass burning emissions in the SE Asia subcontinent. Ozone and trace gas measurement on board the DC-8 aircraft revealed that O-3-rich air masses are found over many parts of the tropical SE Asia and subtropical western Pacific regions and they have similar chemical characteristics. The accompanying trace gas measurements suggest that the O-3-rich air masses are rich in biomass burning tracer, CH3Cl, but not the general urban emission tracers. We thus believe that the springtime O-3 enhancement over Hong Kong is as a result of transport of photochemical O-3 produced from biomass burning emissions from the upwind SE Asian continent. The large-scale enhancements of O-3 in tropical SE Asia and the subtropical western Pacific rim that result from SE Asian biomass burning activities such as presented here thus are of atmospheric importance and deserve further research efforts.