1

Non-stationary Synchronization of Equatorial QBO with SAO in

Observation and Model

Non-stationary Synchronization of Equatorial QBO with SAO in

Observation and Model

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

Le Kuai1, Run-Lie Shia1, Xun Jiang2, Ka-Kit Tung3, Yuk L. Yung1

2

Quasi-Biennial Oscillation (QBO)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

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

Symmetric about

equator: 12°

In ozone & T

Transported to polar

region

3

MotivationsMotivations

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

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 ExperimentsPerpetual Solar Forcing Modeling Experiments

Advantages

• Longer time period

• Without volcanic influence

• The solar radiation perpetual condition

THINAIR (Two and a Half dimensional INterActive THINAIR (Two and a Half dimensional INterActive Isentropic Research) ModelIsentropic 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)

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

• 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

QBO-SAO Synchronization – Observation (ERA-40)

QBO-SAO Synchronization – Observation (ERA-40)

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 – ModelQBO-SAO Synchronization – ModelSolar cycle varying case

• Quantum jump

• Non-stationary

manner4-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

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

QBO-SAO Synchronization – ModelQBO-SAO Synchronization – ModelPerpetual 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

3cT

F4-SAO

5-SAO

12

ConclusionsConclusionsThe 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?Solar Cycle Modulation on QBO period?

Short term period:

• Correlation

• Anti-correlation

• no relation

Need much longer period

Le Kuai, Run-Lie Shia, Xun Jiang, Ka-Kit Tung, Yuk L. Yung

14

AcknowledgementAcknowledgement

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

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

15

Solar cycle modulation on QBO periodSolar cycle modulation on QBO period

Cases Mean QBO period

(a) 15×SC-min 24.64

(b) 10×SC-min 25.66

(c) SC-mean 27.20

(d) 5×SC-max 26.67

(e) 10×SC-min 28.43

(d) 15×SC-min 29.04

16

17

18

The MotivationsThe 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.

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.

19

Previous work:Debate on the 11-year solar cycle modulation of the QBO period

Previous work:Debate on the 11-year solar cycle modulation of the QBO period

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

Anti-correlation

20

THINAIR modelTHINAIR 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

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

21

QBO mechanismQBO mechanism

22

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).

23

Holton-Tan Mechanism

24

Stream function: easterly – westerlyStream function: easterly – westerly

25

Solar condition Mean QBO period (Month)

3SC-min 24.00

2SC-min 24.00

1SC-min 25.08

SC-mean 28.59

1SC-max 31.85

2SC-max 36.01

3SC-max 38.29

26

The thermal wind balance equationThe thermal wind balance equation

y uz

R

H

Ty

H RTg

Westerly wind warm

Easterly wind cold

T perturbation~ 3 K at the equator