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The quasi-biennial oscillation (QBO) and global-scale tropical waves in Aeolus wind observations, radiosonde data, and reanalyses

Ern, Manfred and Diallo, Mohamadou and Khordakova, Dina and Krisch, Isabell and Preusse, Peter and Reitebuch, Oliver and Ungermann, Jörn and Riese, Martin (2023) The quasi-biennial oscillation (QBO) and global-scale tropical waves in Aeolus wind observations, radiosonde data, and reanalyses. Atmospheric Chemistry and Physics (ACP), 23, pp. 9549-9583. Copernicus Publications. doi: 10.5194/acp-23-9549-2023. ISSN 1680-7316.

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Official URL: https://acp.copernicus.org/articles/23/9549/2023/


The quasi-biennial oscillation (QBO) of the stratospheric tropical winds influences the global circulation over a wide range of latitudes and altitudes. Although it has strong effects on surface weather and climate, climate models have great difficulties in simulating a realistic QBO, especially in the lower stratosphere. Therefore, global wind observations in the tropical upper troposphere and lower stratosphere (UTLS) are of particular interest for investigating the QBO and the tropical waves that contribute significantly to its driving. In our work, we focus on the years 2018-2022 and investigate the QBO and different tropical wave modes in the UTLS region using global wind observations made by the Aeolus satellite instrument and three meteorological reanalyses: the fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA-5), the Japanese 55-year Reanalysis (JRA-55) of the Japan Meteorological Agency (JMA), and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). Further, we compare these data with observations of selected radiosonde stations. By comparison with Aeolus observations, we find that, on zonal average, the QBO in the lower stratosphere is well represented in all three reanalyses, with ERA-5 performing best. Averaged over the years 2018-2022, agreement between Aeolus and the reanalyses is better than 1 to 2 m/s, with somewhat larger differences during some periods. Differently from zonal averages, radiosonde stations provide only local observations and are therefore biased by global-scale tropical waves, which limits their use as a QBO standard. While reanalyses perform well on zonal average, there can be considerable local biases between reanalyses and radiosondes. We also find that, in the tropical UTLS, zonal wind variances of stationary waves and the most prominent global-scale traveling equatorial wave modes, such as Kelvin waves, Rossby-gravity waves, and equatorial Rossby waves, are in good agreement between Aeolus and all three reanalyses (in most cases better than 20 % of the peak values in the UTLS). On zonal average, this supports the use of reanalyses as a reference for comparison with free-running climate models, while locally, certain biases exist, particularly in the QBO wind shear zones and around the 2019-2020 QBO disruption.

Item URL in elib:https://elib.dlr.de/196836/
Document Type:Article
Title:The quasi-biennial oscillation (QBO) and global-scale tropical waves in Aeolus wind observations, radiosonde data, and reanalyses
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Ern, ManfredFZ Jülich, Jülich, Germanyhttps://orcid.org/0000-0002-8565-2125UNSPECIFIED
Diallo, MohamadouFZ Jülich, Jülich, GermanyUNSPECIFIEDUNSPECIFIED
Khordakova, DinaFZ Jülich, Jülich, GermanyUNSPECIFIEDUNSPECIFIED
Krisch, IsabellDLR, IPAhttps://orcid.org/0000-0001-6646-7277UNSPECIFIED
Preusse, PeterFZ Jülich, Jülich, GermanyUNSPECIFIEDUNSPECIFIED
Reitebuch, OliverDLR, IPAhttps://orcid.org/0000-0002-8503-0094UNSPECIFIED
Ungermann, JörnFZ Jülich, Jülich, Germanyhttps://orcid.org/0000-0001-9095-8332UNSPECIFIED
Riese, MartinFZ Jülich, Jülich, Germanyhttps://orcid.org/0000-0001-6398-6493UNSPECIFIED
Date:29 August 2023
Journal or Publication Title:Atmospheric Chemistry and Physics (ACP)
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In ISI Web of Science:Yes
Page Range:pp. 9549-9583
Publisher:Copernicus Publications
Keywords:Atmospheric Dynamics; quasi-biennial oscillation; Aeolus; reanalyses
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 - Project ADM III cont.
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Lidar
Deposited By: Krisch, Isabell
Deposited On:30 Aug 2023 10:35
Last Modified:30 Aug 2023 10:35

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