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Indication of low ozone anomaly in Arctic Spring during QBO-westerly and solar-minimum years
  • Yousuke Yamashita,
  • Hideharu Akiyoshi,
  • Masaaki Takahashi
Yousuke Yamashita
National Institute for Environmental Studies
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Hideharu Akiyoshi
Natinal Institute for Environmental Studies

Corresponding Author:[email protected]

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Masaaki Takahashi
Atmosphere and Ocean Research Institute, University of Tokyo
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Abstract

This study investigates the influence of the phase of quasi-biennial oscillation (QBO) and the 11-year solar cycle on the Arctic spring ozone, using satellite observations, reanalysis data, and outputs of a chemistry climate model (CCM) during the period of 1979–2011. For this duration, we found that the composite mean of the Northern Hemisphere high-latitude total ozone in the QBO-westerly (QBO-W)/solar minimum (S) phase indicates a large negative anomaly for the climatology in February–March. An analysis of the passive ozone tracer defined at the pressure levels between 220 hPa and 12 hPa in the CCM simulation indicates that this negative anomaly is primarily caused by transport. The negative anomaly is consistent with a weakening of the residual mean downward motion in the polar lower stratosphere. The contribution of chemical processes estimated using the total ozone difference between the chemically active ozone runs and the passive tracer simulations is less than 6% of the total anomaly in February and between 10–20% in March. The lower ozone levels in the Arctic spring during the QBO-W/Syears are associated with a stronger Arctic polar vortex from late winter to early spring, which is linked to the reduced occurrence of sudden stratospheric warming in the winter during the QBO-W/Syears.