Non-stationary%20Synchronization%20of%20Equatorial%20QBO%20with%20SAO%20in%20Observation%20and%20Model

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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
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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

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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

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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

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

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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

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

• Quantum jump
• Non-stationary
• manner

ERA-40
4-SAO
5-SAO
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QBO-SAO Synchronization in Observation -
ERA-40 QBO-SAO Synchronization in Model -
Solar cycle varying case - Perpetual solar
mean case
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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
Phase speed Kelvin wave Rossby-Gravity wave
c (m s-1) 25 -30

Case A1 / (A1 )baseline A2 / (A2 )baseline
(a) 1 1.1
(b) 1 1
(c) 0.91 1
(d) 0.83 1.05
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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

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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
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Acknowledgement

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

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Solar cycle modulation on QBO period
Cases Mean QBO period
(a) 15SC-min 24.64
(b) 10SC-min 25.66
(c) SC-mean 27.20
(d) 5SC-max 26.67
(e) 10SC-min 28.43
(d) 15SC-min 29.04
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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.

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Previous workDebate on the 11-year solar cycle
modulation of the QBO period
Anti-correlation 19571991 (3 major volcanic
eruptions) Salby Callaghan, 2000
Pascoe, et al, 2005 Soukharev Hood, 2001
Hamilton, 2002 Fischer Tung, 2007 In-phase
relation 19531957 19912005 (Clear
stratosphere) Hamilton, 2002 Fischer
Tung, 2007
Anti-correlation
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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
• gt30 km, peak at 50 km 210-6/s
• lt30 km, constant 0.3510-6/s

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QBO mechanism
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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).

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Holton-Tan Mechanism
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Stream function easterly westerly
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Solar condition Mean QBO period (Month)
3?SC-min 24.00
2?SC-min 24.00
1?SC-min 25.08
SC-mean 28.59
1?SC-max 31.85
2?SC-max 36.01
3?SC-max 38.29
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The thermal wind balance equation
Westerly wind warm Easterly wind cold T
perturbation 3 K at the equator