气候变化领域集成服务门户(CCPortal): Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems

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DOI	10.5194/acp-21-2343-2021
	Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems
	Lakshmi Narayanan V.; Nozawa S.; Oyama S.-I.; Mann I.; Shiokawa K.; Otsuka Y.; Saito N.; Wada S.; Kawahara T.D.; Takahashi T.
发表日期	2021
ISSN	1680-7316
起始页码	2343
结束页码	2361
卷号	21 期号:4
英文摘要	We present a detailed investigation of the formation of an additional sodium density peak at altitudes of 79-85 km below the main peak of the sodium layer based on sodium lidar and airglow imager measurements made at Ramfjordmoen near Tromsø, Norway, on the night of 19 December 2014. The airglow imager observations of OH emissions revealed four passing frontal systems that resembled mesospheric bores, which typically occur in ducting regions of the upper mesosphere. For about 1.5 h, the lower-altitude sodium peak had densities similar to that of the main peak of the layer around 90 km. The lower-altitude sodium peak weakened and disappeared soon after the fourth front had passed. The fourth front had weakened in intensity by the time it approached the region of lidar beams and disappeared soon afterwards. The column-integrated sodium densities increased gradually during the formation of the lower-altitude sodium peak. Temperatures measured with the lidar indicate that there was a strong thermal duct structure between 87 and 93 km. Furthermore, the temperature was enhanced below 85 km. Horizontal wind magnitudes estimated from the lidar showed strong wind shears above 93 km. We conclude that the combination of an enhanced stability region due to the temperature profile and intense wind shears have provided ideal conditions for evolution of multiple mesospheric bores revealed as frontal systems in the OH images. The downward motion associated with the fronts appeared to have brought air rich in H and O from higher altitudes into the region below 85 km, wherein the temperature was also higher. Both factors would have liberated sodium atoms from the reservoir species and suppressed the reconversion of atomic sodium into reservoir species so that the lower-altitude sodium peak could form and the column abundance could increase. The presented observations also reveal the importance of mesospheric frontal systems in bringing about significant variation of minor species over shorter temporal intervals. © 2021 EDP Sciences. All rights reserved.
语种	英语
scopus关键词	airglow; atmospheric chemistry; lidar; mesosphere; reservoir characterization; sodium; stability analysis; thermal structure; trace element; Norway; Troms; Tromso
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/247138
作者单位	Department of Physics and Technology, UiT - the Arctic University of Norway, Tromsø, Norway; Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan; Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland; National Institute of Polar Research, Tokyo, Japan; Riken Center for Advanced Photonics, Riken, Saitama, Japan; Faculty of Engineering, Shinshu University, Nagano, Japan; Department of Physics, University of Oslo, Oslo, Norway; Electronic Navigation Research Institute, National Institute of Maritime, Port, and Aviation Technology, Tokyo, Japan
推荐引用方式 GB/T 7714	Lakshmi Narayanan V.,Nozawa S.,Oyama S.-I.,et al. Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems[J],2021,21(4).
APA	Lakshmi Narayanan V..,Nozawa S..,Oyama S.-I..,Mann I..,Shiokawa K..,...&Takahashi T..(2021).Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(4).
MLA	Lakshmi Narayanan V.,et al."Formation of an additional density peak in the bottom side of the sodium layer associated with the passage of multiple mesospheric frontal systems".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.4(2021).