气候变化领域集成服务门户(CCPortal): Upper tropospheric CH 4 and CO affected by the South Asian summer monsoon during the Oxidation Mechanism Observations mission

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DOI	10.5194/acp-19-1915-2019
	Upper tropospheric CH 4 and CO affected by the South Asian summer monsoon during the Oxidation Mechanism Observations mission
	Tomsche L.; Pozzer A.; Ojha N.; Parchatka U.; Lelieveld J.; Fischer H.
发表日期	2019
ISSN	16807316
起始页码	1915
结束页码	1939
卷号	19 期号:3
英文摘要	The Asian monsoon anticyclone (AMA) is annual phenomenon in the northern hemispheric upper troposphere and lower stratosphere. It is part of the South Asian summer monsoon system, and it has a clearly observable signature due to the vertical transport of polluted air masses from the surface to the upper troposphere by monsoon convection. We performed in situ measurements of carbon monoxide (CO) and methane (CH 4 ) in the region of monsoon outflow and in background air in the upper troposphere (Mediterranean, Arabian Peninsula, and Arabian Sea) using optical absorption spectroscopy on board the High Altitude and LOng range (HALO) research aircraft during the OMO (Oxidation Mechanism Observations) mission in summer 2015. We identified the transport pathways and the origin of the trace gases with back trajectories, which were calculated using the Lagrangian particle dispersion model FLEXPART, and we compared the in situ data with simulations of the atmospheric chemistry general circulation model EMAC. CH 4 and CO mixing ratios were found to be enhanced within the AMA, the in situ data increased by 72.1 and 20.1 ppbv on average, respectively, and originated in the South Asian region (Indo-Gangetic Plain, northeastern India, Bangladesh, and the Bay of Bengal). It appears that CH 4 is an ideal monsoon tracer in the upper troposphere due to its extended lifetime and the strong South Asian emissions. Furthermore, we used the measurements and model results to study the dynamics of the AMA over several weeks during the monsoon season, with an emphasis on the southern and western areas in the upper troposphere. We distinguished four AMA modes based on different meteorological conditions. On one occasion we observed that under the influence of dwindling flow the transport barrier between the anticyclone and its surroundings weakened, expelling air masses from the AMA. The trace gases exhibited a distinct AMA fingerprint; we also found that CH 4 accumulated over the course of the OMO campaign. © 2019 Author(s).
语种	英语
scopus关键词	carbon monoxide; in situ measurement; methane; monsoon; oxidation; summer; trace gas; troposphere; Arabian Peninsula; Arabian Sea; Bangladesh; Bay of Bengal; Gangetic Plain; India; Indian Ocean; Mediterranean Sea
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144645
作者单位	Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, 55128, Germany
推荐引用方式 GB/T 7714	Tomsche L.,Pozzer A.,Ojha N.,et al. Upper tropospheric CH 4 and CO affected by the South Asian summer monsoon during the Oxidation Mechanism Observations mission[J],2019,19(3).
APA	Tomsche L.,Pozzer A.,Ojha N.,Parchatka U.,Lelieveld J.,&Fischer H..(2019).Upper tropospheric CH 4 and CO affected by the South Asian summer monsoon during the Oxidation Mechanism Observations mission.Atmospheric Chemistry and Physics,19(3).
MLA	Tomsche L.,et al."Upper tropospheric CH 4 and CO affected by the South Asian summer monsoon during the Oxidation Mechanism Observations mission".Atmospheric Chemistry and Physics 19.3(2019).