气候变化领域集成服务门户(CCPortal): Mixing at the extratropical tropopause as characterized by collocated airborne H2O and O3lidar observations

CCPortal

DOI	10.5194/acp-21-5217-2021
	Mixing at the extratropical tropopause as characterized by collocated airborne H2O and O3lidar observations
	Schäfler A.; Fix A.; Wirth M.
发表日期	2021
ISSN	1680-7316
起始页码	5217
结束页码	5234
卷号	21 期号:6
英文摘要	The composition of the extratropical transition layer (ExTL), which is the transition zone between the stratosphere and the troposphere in the midlatitudes, largely depends on dynamical processes fostering the exchange of air masses. The Wave-driven ISentropic Exchange (WISE) field campaign in 2017 aimed for a better characterization of the ExTL in relation to the dynamic situation. This study investigates the potential of the first-ever collocated airborne lidar observations of ozone (O3) and water vapor (H2O) across the tropopause to depict the complex trace gas distributions and mixing in the ExTL. A case study of a perpendicular jet stream crossing with a coinciding strongly sloping tropopause is presented that was observed during a research flight over the North Atlantic on 1 October 2017. The collocated and range-resolved lidar data that are applied to established tracer-tracer (T-T) space diagnostics prove to be suitable to identify the ExTL and to reveal distinct mixing regimes that enabled a subdivision of mixed and tropospheric air. A back projection of this information to geometrical space shows remarkably coherent structures of these air mass classes along the cross section. This represents the first almost complete observation-based twodimensional (2D) illustration of the shape and composition of the ExTL and a confirmation of established conceptual models. The trace gas distributions that represent typical H2O and O3values for the season reveal tropospheric transport pathways from the tropics and extratropics that have influenced the ExTL. Although the combined view of T-T and geometrical space does not inform about the process, location and time of the mixing event, it gives insight into the formation and interpretation of mixing lines. A mixing factor diagnostic and a consideration of data subsets show that recent quasi-instantaneous isentropic mixing processes impacted the ExTL above and below the jet stream which is a confirmation of the well-established concept of turbulenceinduced mixing in strong wind shear regions. At the level of maximum winds reduced mixing is reflected in jumps in T-T space that occurred over small horizontal distances along the cross section. For a better understanding of the dynamical and chemical discontinuities at the tropopause, the lidar data are illustrated in isentropic coordinates. The strongest gradients of H2O and O3are found to be better represented by a potential vorticity-gradient-based tropopause compared to traditional dynamical tropopause definitions using constant potential vorticity values. The presented 2D lidar data are considered to be of relevance for the investigation of further meteorological situations leading to mixing across the tropopause and for future validation of chemistry and numerical weather prediction models. © 2019 EDP Sciences. All rights reserved.
语种	英语
scopus关键词	air mass; lidar; ozone; satellite data; satellite imagery; stratosphere-troposphere interaction; trace gas; tropopause; vorticity; water vapor
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/247000
作者单位	Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
推荐引用方式 GB/T 7714	Schäfler A.,Fix A.,Wirth M.. Mixing at the extratropical tropopause as characterized by collocated airborne H2O and O3lidar observations[J],2021,21(6).
APA	Schäfler A.,Fix A.,&Wirth M..(2021).Mixing at the extratropical tropopause as characterized by collocated airborne H2O and O3lidar observations.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(6).
MLA	Schäfler A.,et al."Mixing at the extratropical tropopause as characterized by collocated airborne H2O and O3lidar observations".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.6(2021).