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Non-stationary Synchronization of Equatorial QBO with SAO in Observation and Model

Non-stationary Synchronization of Equatorial QBO with SAO in Observation and Model. Le Kuai 1 , Run-Lie Shia 1 , Xun Jiang 2 , Ka-Kit Tung 3 , Yuk L. Yung 1.

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Non-stationary Synchronization of Equatorial QBO with SAO in Observation and Model

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  1. Non-stationary Synchronization of Equatorial QBO with SAO in Observation and Model Le Kuai1, Run-Lie Shia1, Xun Jiang2, Ka-Kit Tung3, Yuk L. Yung1 1.Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 911252. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 911093. Department of Applied Mathematics, University of Washington, Seattle, WA 98195

  2. Quasi-Biennial Oscillation (QBO) • Westward and eastward wind regimes periodically repeat • Average period: 28 months; Inter-annual variability: 22-34 months • Propagate downwards: 1 km/month • Maxima amplitude: ~20 m/s Baldwin et al. [2001] • Symmetric about equator: 12° • In ozone & T • Transported to polar region

  3. Motivations 1) Underemphasized features: • Synchronization with the Semi-Annual Oscillation (SAO) • Random quantum jumps of QBO period 2) Debates on the 11-year solar cycle modulation of the QBO period • Anti-correlation/Correlation • Volcanic aerosols  Clear stratosphere • Short observational records

  4. Perpetual Solar Forcing Modeling Experiments • Advantages • Longer time period • Without volcanic influence • The solar radiation perpetual condition • THINAIR (Two and a Half dimensional INterActive Isentropic Research) Model • Chemical-radiative-dynamical model • Isentropic vertical coordinate, 29 layers up to 100 km • 19 meridional grids from pole to pole • The QBO-source term: parameterization

  5. QBO-SAO Synchronization in Observation - ERA-40 QBO-SAO Synchronization in Model - Solar cycle varying case - Perpetual solar mean case

  6. QBO-SAO Synchronization – Observation (ERA-40) • 2-7 hPa region: • The presence of both the QBO and SAO • Transitions to the QBO below • Removed QBO: • The w-QBO starts with a w-SAO (Why?) • QBO period is an integer multiple of the SAO period

  7. QBO-SAO Synchronization – Observation (ERA-40) • Quantum jumps in integral multiples of SAO periods. • No correlation/anti-correlation with the 11-year solar cycle • Mean QBO period: 27.7 months • Period about constant with height

  8. QBO-SAO Synchronization in Observation - ERA-40 QBO-SAO Synchronization in Model - Solar cycle varying case - Perpetual solar mean case

  9. QBO-SAO Synchronization – Model Solar cycle varying case • Quantum jump • Non-stationary • manner ERA-40 4-SAO 5-SAO

  10. QBO-SAO Synchronization in Observation - ERA-40 QBO-SAO Synchronization in Model - Solar cycle varying case - Perpetual solar mean case

  11. QBO-SAO Synchronization – Model Perpetual solar mean case The non-stationary jumps in QBO period are not a result of the solar cycle The intrinsic period is determined by wave forcing 4-SAO 5-SAO

  12. Conclusions • The initiation of the w-QBO synchronized with the w-SAO  the QBO period in the upper stratosphere should be an integer multiple of the SAO period • The non-stationary jumps under perpetual solar forcing  the intrinsic period of the QBO determined by the wave-mean flow system

  13. Solar Cycle Modulation on QBO period? • Short term period: • Correlation • Anti-correlation • no relation • Need much longer period Coming soon! The Modulation of the Period of the Qusi-Biennial Oscillation by the Solar Cycle Le Kuai, Run-Lie Shia, Xun Jiang, Ka-Kit Tung, Yuk L. Yung

  14. Acknowledgement • Yuk L. Yung • Run-Lie Shia • Ka-Kit Tung • Xun Jiang

  15. Solar cycle modulation on QBO period

  16. The Motivations • The effects on chemical constituents • The effect on the wintertime stratospheric polar vortices and SSW events. • Controversy of the 11-year solar cycle modulation on QBO periods.

  17. Anti-correlation: 1957~1991 (3 major volcanic eruptions) Salby & Callaghan, 2000; Pascoe, et al, 2005; Soukharev & Hood, 2001; Hamilton, 2002; Fischer & Tung, 2007 In-phase relation: 1953~1957 & 1991~2005 (Clear stratosphere) Hamilton, 2002; Fischer & Tung, 2007 Previous work:Debate on the 11-year solar cycle modulation of the QBO period Anti-correlation

  18. THINAIR model • Solve the continuity, momentum, thermal wind and thermodynamic equations in isentropic surface. • Parameterization for waves • UARS/SOLSTICE spectral irradiance observation for 11-year solar cycle • Dynamics: ground ~ 100 Km • Chemistry: ground ~ 60 Km • Thermal damping rate >30 km, peak at 50 km ~ 2*10-6/s <30 km, constant 0.35*10-6/s

  19. QBO mechanism

  20. QBO induced circulation and its modulation of the Column Ozone • When the QBO is in the westerly (easterly) phase, there is descending (upwelling) anomalous motion in the tropical stratosphere and upwelling (descending) anomalous motion in the subtropical stratosphere (Plumb and Bell, 1982). • This results in more (less) ozone at the equator in the westerly (easterly) QBO phase (Tung and Yang, 1994a).

  21. Holton-Tan Mechanism

  22. Stream function: easterly – westerly

  23. The thermal wind balance equation Westerly wind warm Easterly wind cold T perturbation~ 3 K at the equator

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