Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 6813-6823, 2017
https://doi.org/10.5194/acp-17-6813-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
12 Jun 2017
Response of trace gases to the disrupted 2015–2016 quasi-biennial oscillation
Olga V. Tweedy1, Natalya A. Kramarova2,4, Susan E. Strahan3,4, Paul A. Newman4, Lawrence Coy2, William J. Randel5, Mijeong Park5, Darryn W. Waugh1, and Stacey M. Frith2,4 1Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
2Science Systems and Applications Inc., Lanham, MD, USA
3Universities Space Research Association, Columbia, MD, USA
4NASA, GSFC, Greenbelt, MD, USA
5National Center for Atmospheric Research, Boulder, CO, USA
Abstract. The quasi-biennial oscillation (QBO) is a quasiperiodic alternation between easterly and westerly zonal winds in the tropical stratosphere, propagating downward from the middle stratosphere to the tropopause with a period that varies from 24 to 32 months ( ∼  28 months on average). The QBO wind oscillations affect the distribution of chemical constituents, such as ozone (O3), water vapor (H2O), nitrous oxide (N2O), and hydrochloric acid (HCl), through the QBO-induced meridional circulation. In the 2015–2016 winter, radiosonde observations revealed an anomaly in the downward propagation of the westerly phase, which was disrupted by the upward displacement of the westerly phase from  ∼  30 hPa up to 15 hPa and the sudden appearance of easterlies at 40 hPa. Such a disruption is unprecedented in the observational record from 1953 to the present. In this study we show the response of trace gases to this QBO disruption using O3, HCl, H2O, and temperature from the Aura Microwave Limb Sounder (MLS) and total ozone measurements from the Solar Backscatter Ultraviolet (SBUV) Merged Ozone Data Set (MOD). Results reveal the development of positive anomalies in stratospheric equatorial O3 and HCl over  ∼  50–30 hPa in May–September of 2016 and a substantial decrease in O3 in the subtropics of both hemispheres. The SBUV observations show near-record low levels of column ozone in the subtropics in 2016, resulting in an increase in the surface UV index during northern summer. Furthermore, cold temperature anomalies near the tropical tropopause result in a global decrease in stratospheric water vapor.

Citation: Tweedy, O. V., Kramarova, N. A., Strahan, S. E., Newman, P. A., Coy, L., Randel, W. J., Park, M., Waugh, D. W., and Frith, S. M.: Response of trace gases to the disrupted 2015–2016 quasi-biennial oscillation, Atmos. Chem. Phys., 17, 6813-6823, https://doi.org/10.5194/acp-17-6813-2017, 2017.
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In this study we examined the impact of unprecedented disruption in the wind pattern (the quasi-biennial oscillation, or QBO) in the tropical stratosphere (16–48 km above the ground) on chemicals very important to the stratospheric climate such as ozone (O3). During the 2016 boreal summer, total O3 is lower in the extratropics than during previous QBO cycles due to lifting forced from the disruption. This decrease in O3 led to the increase in surface UV index by 8.5 % compared to the 36 yr mean.
In this study we examined the impact of unprecedented disruption in the wind pattern (the...
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