气候变化领域集成服务门户(CCPortal): Impact of convection on the upper-tropospheric composition (water vapor and ozone) over a subtropical site (Réunion island; 21.1° S, 55.5° E) in the Indian Ocean

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DOI	10.5194/acp-20-8611-2020
	Impact of convection on the upper-tropospheric composition (water vapor and ozone) over a subtropical site (Réunion island; 21.1° S, 55.5° E) in the Indian Ocean
	Héron D.; Evan S.; Brioude J.; Rosenlof K.; Posny F.; Metzger J.-M.; Cammas J.-P.
发表日期	2020
ISSN	16807316
起始页码	8611
结束页码	8626
卷号	20 期号:14
英文摘要	Observations of ozonesonde measurements of the NDACC/SHADOZ (Network for the Detection of Atmospheric Composition Change and the Southern Hemisphere ADditional OZonesondes) program and humidity profiles from the daily Météo-France radiosondes at Réunion island (21.1° S, 55.5° E) from November 2013 to April 2016 were analyzed to identify the origin of wet upper-tropospheric air masses with low ozone mixing ratio observed above the island, located in the southwest Indian Ocean (SWIO). A seasonal variability in hydration events in the upper troposphere was found and linked to the convective activity within the SWIO basin. In the upper troposphere, ozone mixing ratios were lower (mean of 57 ppbv) in humid air masses (RH > 50 %) compared to the background mean ozone mixing ratio (73.8 ppbv). A convective signature was identified in the ozone profile dataset by studying the probability of occurrence of different ozone thresholds. It was found that ozone mixing ratios lower than 45 to 50 ppbv had a local maximum of occurrence between 10 and 13 km in altitude, indicative of the mean level of convective outflow. Combining FLEXPART Lagrangian back trajectories with METEOSAT-7 infrared brightness temperature products, we established the origin of convective influence on the upper troposphere above Réunion island. It has been found that the upper troposphere above Réunion island is impacted by convective outflows in austral summer. Most of the time, deep convection is not observed in the direct vicinity of the island, but it is observed more than 1000 km away from the island, in the tropics, either from tropical storms or the Intertropical Convection Zone (ITCZ). In November and December, the air masses above Réunion island originate, on average, from central Africa and the Mozambique Channel. During January and February the source region is the northeast of Mozambique and Madagascar. Those results improve our understanding of the impact of the ITCZ and tropical cyclones on the hydration of the upper troposphere in the subtropics in the SWIO. © 2020 Author(s).
语种	英语
scopus关键词	atmospheric chemistry; convection; hydration; ozone; ozonesonde; seasonal variation; subtropical region; troposphere; water vapor; Indian Ocean; Mascarene Islands; Reunion
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/152873
作者单位	LACy, Laboratoire de l'Atmosphère et des Cyclones, UMR8105, Cnrs, Université de la Réunion, Météo-France, Saint-Denis, La Réunion, France; Chemical Sciences Division, Earth System Research Laboratory, Noaa, Boulder, CO, United States; Observatoire des Sciences de l'Univers de la Réunion, UMS3365, Cnrs, Université de la Réunion, Météo-France, Saint-Denis, La Réunion, France
推荐引用方式 GB/T 7714	Héron D.,Evan S.,Brioude J.,et al. Impact of convection on the upper-tropospheric composition (water vapor and ozone) over a subtropical site (Réunion island; 21.1° S, 55.5° E) in the Indian Ocean[J],2020,20(14).
APA	Héron D..,Evan S..,Brioude J..,Rosenlof K..,Posny F..,...&Cammas J.-P..(2020).Impact of convection on the upper-tropospheric composition (water vapor and ozone) over a subtropical site (Réunion island; 21.1° S, 55.5° E) in the Indian Ocean.Atmospheric Chemistry and Physics,20(14).
MLA	Héron D.,et al."Impact of convection on the upper-tropospheric composition (water vapor and ozone) over a subtropical site (Réunion island; 21.1° S, 55.5° E) in the Indian Ocean".Atmospheric Chemistry and Physics 20.14(2020).