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Quasi-4-day Wave: Atmospheric Manifestation of the First Symmetric Rossby Normal Mode of Zonal Wavenumber 2

Yamazaki, Yosuke and Matthias, Vivien and Miyoshi, Yasunobu (2021) Quasi-4-day Wave: Atmospheric Manifestation of the First Symmetric Rossby Normal Mode of Zonal Wavenumber 2. Journal of Geophysical Research: Atmospheres. Wiley. doi: 10.1029/2021JD034855. ISSN 2169-897X.

[img] PDF - Postprint version (accepted manuscript)

Official URL: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021JD034855


This paper describes global characteristics of the westward-propagating planetary wave with a period of ∼4 days and zonal wavenumber 2, here referred to as quasi-4-day wave (Q4DW), which is considered to be a manifestation of the (2,1) Rossby normal mode. A climatology of the Q4DW is derived from geopotential height measurements by the Aura Microwave Limb Sounder during August 2004–December 2020. In the mesosphere and lower thermosphere (MLT), amplitude maxima occur at mid latitudes in May and August in the Northern Hemisphere, and in February and November in the Southern Hemisphere. With the amplitude exceeding 300 m, the Q4DW sometimes becomes the dominant mode of traveling planetary waves in the MLT. The seasonal variation is largely determined by the zonal mean state. As predicted by previous modeling work, the amplitude grows rapidly with height on the equatorward side of the critical layer, where the zonal mean flow is weakly eastward relative to the wave. The wave growth can be particularly large when there is a region of unstable mean flow across the boundary of the critical layer. This condition is met not only during the seasonal amplification of the Q4DW but also during some Arctic sudden stratospheric warming events, leading to an unseasonal enhancement. This article is protected by copyright. All rights reserved.

Item URL in elib:https://elib.dlr.de/143039/
Document Type:Article
Title:Quasi-4-day Wave: Atmospheric Manifestation of the First Symmetric Rossby Normal Mode of Zonal Wavenumber 2
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Yamazaki, YosukeHelmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany,UNSPECIFIEDUNSPECIFIED
Miyoshi, YasunobuKyushu University, Fukuoka, JapanUNSPECIFIEDUNSPECIFIED
Date:23 June 2021
Journal or Publication Title:Journal of Geophysical Research: Atmospheres
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Keywords:quasi-4-day wave, Rossby wave, mesosphere, lower thermosphere, sudden stratospheric warming, Aura Microwave Limb Sounder
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Middle Atmosphere
Location: Neustrelitz
Institutes and Institutions:Institute for Solar-Terrestrial Physics > Solar-Terrestrial Coupling Processes
Deposited By: Wendt, Dr. Vivien
Deposited On:09 Jul 2021 14:00
Last Modified:28 Jun 2023 13:34

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