stratospheric dynamics and chemistry

Stratospheric Dynamics and Stratospheric Dynamics and

ChemistryChemistry

Michel Bourqui, Farid Ait Chaalal, Thomas Milevski, Ryan Muncaster, Andrew Ryzhkov, Barbara Winter

What is the Stratosphere ?

Winter Summer

WMO, Scientific Assessment of Ozone Depletion: 2002

How is the Stratosphere Working ?

Source: eiu.edu

Vertical structure of the temperature

The Global Circulation

Tropospheric circulation

Stratospheric circulation

Summer Winter

W = westerly wind

E = easterly wind

The Global Circulation

Stratospheric polar vortex

Summer Winter

W = westerly wind

E = easterly wind

The stratospheric chemistry

tropopause

stratopause

Pole PoleEquator

The stratospheric chemistry

tropopause

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

tropopause

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

OO3

tropopause

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

OO3

tropopause

HO2OH

O3

HO2OH

O3

HO2OH

O3

HO2OH

O3

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

OO3

tropopause

HO2OH

O3

NO2NO

O3

HO2OH

O3

HO2OH

O3

NO2NO

O3

HO2OH

O3

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

OO3

tropopause

ClOCl

O3

HO2OH

O3

NO2NO

O3

HO2OH

O3

HO2OH

O3

NO2NO

O3

HO2OH

O3

Summer Winter

stratopause

Pole PoleEquator

The stratospheric chemistry

O2 O3

UV

OO3

tropopause

ClOCl

O3

HO2OH

O3

NO2NO

O3

HO2OH

O3

HO2OH

O3

NO2NO

O3

HO2OH

O3

Summer Winter

stratopause

Pole PoleEquator

densitédensitédensity

1012 molecules cm-3

Ozone concentration, averaged along parallels, forDec – Jan – Feb of 1979 (pre- ozone hole period)

Morphology of the ozone layerA

ltitu

de (

km)

Ozone layer

Chemistry

How is the Stratosphere Working ?

Radiation

Dynamics/Transport

Middle atmosphere:

Chemistry

How is the Stratospere Working ?

Radiation

Dynamics/Transport

Lower atmosphere:

Recent Advances in Stratospheric Research

Modelling:

• 3D Chemistry-Climate Models: first inter-comparison 2002

• Chemical data assimilation: research is starting now…

Observation:

• Ozone observation by satellite since 1990s

• Envisat (EU) satellite: launched March 2002 (chemical composition)

• Aura (USA) satellite: launched January 2004 (chemical composition)

• ACE (CA) satellite: launched May 2003 (chemical composition)

• ADM (EU) satellite: will be launched in 2007 (winds)

• WINDII (CA) satellite: projected for 2009 (winds)

Our current research

• Effect of climate change on the ozone layer

• Development of a fast chemistry scheme

• Chemical data assimilation

• Transport, mixing and chemistry

• Non-linear chemistry in turbulent flows

• Stratosphere-troposphere exchange

• Solar variability and ozone layer

Our current research

• Effect of climate change on the ozone layer

• Development of a fast chemistry scheme

• Chemical data assimilation

• Transport, mixing and chemistry

• Non-linear chemistry in turbulent flows

• Stratosphere-troposphere exchange

• Solar variability and ozone layer

The effet of climate change on the Ozone Layer

CFC scenario (A1), tropospheric concentration, (WMO 1998)

(DU)

(DU)

Ozone column observations (ground-based, WMO 1998)

Ozone depletion due to CFCs

3D Chemistry-Climate Model Forecasts of Ozone Recovery(From Austin et al. 2003)

3D Chemistry-Climate Model Forecasts of Ozone Recovery(From Austin et al. 2003)

Animation_2.wmv

CO2 CH4

N2O

Changes in stratospheric ozone between 1979 and 2060?

CFCs

(WMO 1998, WMO 2001)

Animation_2.wmv

Effects of Greenhouse Gases on Ozone Layer ?

GHG scenarios, tropospheric concentrations (WMO 2001)

Radiative effects (mainly due to CO2)

Dynamical effects (???)

Chemical effects (mainly due to N2O and CH4)

Changes in the distribution of stratospheric ozone

Changes in the total ozone

Potential effects of increasing GHGs on stratospheric ozone:

Increasing concentrations of greenhouse gases (GHGs) : CO2, N2O, CH4, …

(Low concentration of Cly)

Chemical and radiative effects for August

Total ozone change:

Chemical ozone loss slowed down due to temperature decrease

Chemical ozone loss increased due to larger N2O concentration

Total ozone change:

Separated effects of:

N2O

CO2

Chemical and radiative effects for August

Dynamical effects...

Radiative effects (mainly due to CO2)

Dynamical effects (???)

Chemical effects (mainly due to N2O and CH4)

Changes in the distribution of stratospheric ozone

Changes in the total ozone

Potential effects of increasing GHGs on stratospheric ozone:

Increasing concentrations of greenhouse gases (GHGs) : CO2, N2O, CH4, …

(Low concentration of Cly)

Transport, mixing and chemistry

1. Non-linear chemistry in turbulent

flows

2. Stratosphere-troposphere exchange

Transport, mixing and chemistry

WMO, Scientific Assessment of Ozone Depletion: 2002

Winter Summer

Instantaneous tropopause

(2 PVU from ECMWF data)

SH NH

Climatological

tropopause

PVU

Transport, mixing and chemistry

Animation of horizontal cross-section of the tropopause: click here

Transport, mixing and chemistry

A study of the interaction between chemistry and fluid dynamics at the tropopause

Ozone Water vapour OH

Animation of OH: click here

Transport, mixing and chemistry

A study of non-linear chemistry (A+B→C) in turbulent flows

Increasing diffusion,decreasing resolution

time

C c

once

ntra

tion

Transport, mixing and chemistry

Studies of Stratosphere-Troposphere Exchange (STE)

1. High resolution simulation of stratosphere-troposphere exchange episodes

2. Development of a theoretical stochastic model for global STE

3. Characterisation of dilution rate of stratospheric air in the troposphere

4. Impact of STE at the ground and origin of surface air

Transport, mixing and chemistry

Studies of Stratosphere-Troposphere Exchange (STE)

1. High resolution simulation of stratosphere-troposphere exchange episodes

2. Development of a theoretical stochastic model for global STE

3. Characterisation of dilution rate of stratospheric air in the troposphere

4. Impact of STE at the ground and origin of surface air

Transport, mixing and chemistry

Rapid transport between the boundary layer and the stratosphere

WinterStratosphere

Boundary layer

tropopause

700 hPa

Stratosphere

Boundary layer

tropopause

700 hPa

Calculation based upon ERA15 (1979-1993)

Transport, mixing and chemistry

Solar variability and ozone layer

Our approach:

1. Use a magneto-hydrodynamic model of the Sun to generate solar variability (with spectral resolution)

2. Force the photochemical scheme as well as the radiation scheme in our Climate-Chemistry Model troposphere-stratosphere chemistry-climate model.

Solar variability and ozone layer

Froelich& Lean2006

Solar variability and ozone layer

Courtesy: Paul Charbonneau, Universite de Montreal

In Summary:

Research Focus

• Stratosphere• Transport and dynamics• Chemistry• Chemical data assimilation• Ozone layer• Climate• Solar Variability• Future satellite mission STEP

Research Tools

• General Circulation Models• Mesoscale Models• Chemistry models• Trajectory models• Meteorological data (ERA40,…)• Satellite data

Research Infrastructure

• Supercomputer• Desktop computers

Research Collaborations

• University of Toronto• Universite de Montreal• University of Saskatchewan• Canadian Space Agency• MSC (Dorval and Toronto)• University of Reading (UK)• ETHZ (Switzerland)• + many others

http://www.meteo.mcgill.ca/bourqui

http://www.meteo.mcgill.ca/hydroxyl

Office: BH 815

Email: michel.bourqui@mcgill.ca

Further information