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Response of Arctic ozone to sudden stratospheric warmings

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Cámara Illescas, Álvaro de la and Ábalos Álvarez, Marta and Hitchcock, Peter and Calvo Fernández, Natalia and García, Rolando R. (2018) Response of Arctic ozone to sudden stratospheric warmings. Atmospheric Chemistry and Physics, 18 (22). pp. 16499-16513. ISSN 1680-7316

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Official URL: http://dx.doi.org/10.5194/acp-18-16499-2018




Abstract

Sudden stratospheric warmings (SSWs) are the main source of intra-seasonal and interannual variability in the extratropical stratosphere. The profound alterations to the stratospheric circulation that accompany such events produce rapid changes in the atmospheric composition. The goal of this study is to deepen our understanding of the dynamics that control changes of Arctic ozone during the life cycle of SSWs, providing a quantitative analysis of advective transport and mixing. We use output from four ensemble members (60 years each) of the Whole Atmospheric Community Climate Model version 4 performed for the Chemistry Climate Model Initiative and also use reanalysis and satellite data for validation purposes. The composite evolution of ozone displays positive mixing ratio anomalies of up to 0.5-0.6 ppmv above 550 K (similar to 50 hPa) around the central warming date and negative anomalies below (-0.2 to -0.3 ppmv), consistently in observations, reanalysis, and the model. Our analysis shows a clear temporal offset between ozone eddy transport and diffusive ozone fluxes. The initial changes in ozone are mainly driven by isentropic eddy fluxes linked to enhanced wave drag responsible for the SSW. The recovery of climatological values in the aftermath of SSWs is slower in the lower than in the upper stratosphere and is driven by the competing effects of cross-isentropic motions (which work towards the recovery) and isentropic irreversible mixing (which delays the recovery). These features are enhanced in strength and duration during sufficiently deep SSWs, particularly those followed by polar-night jet oscillation (PJO) events. It is found that SSW-induced ozone concentration anomalies below 600 K (similar to 40 hPa), as well as total column estimates, persist around 1 month longer in PJO than in non-PJO warmings.


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© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License. The authors are grateful to Mengchu Tao and the one anonymous referee for their positive assessment and constructive comments. This work has been partially funded by the Spanish national projects PALEOSTRAT (CGL2015-69699) and STEADY (CGL2017-83198-R) and the European project STRATOCLIM (FP7-ENV.2013.6.1-2 ref:603557). Álvaro de la Cámara has been supported by the UCM fellowship program "Personal posdoctoral en formación en investigación y docencia" and Marta Abalos by the research grant Atracción de Talento Comunidad de Madrid (ref 2016-T2/AMB-1405).

Uncontrolled Keywords:Community climate model; Jet oscillation events; Tracer transport; Planetary-waves; Life-cycle; Vortex; Atmosphere; Dynamics; Winter; Parameterization
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:50716
Deposited On:13 Feb 2019 11:30
Last Modified:13 Feb 2019 12:21

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