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Stratospheric Dynamics and Chemistry Michel Bourqui, Farid Ait Chaalal, Thomas Milevski, Ryan Muncaster, Andrew Ryzhkov, Barbara Winter What is the Stratosphere ? Winter WMO, Scientific Assessment of Ozone Depletion: 2002 Summer How is the Stratosphere Working ? Vertical structure of the temperature Source: eiu.edu The Global Circulation Summer W = westerly wind E = easterly wind Stratospheric circulation Tropospheric circulation Winter The Global Circulation Summer W = westerly wind E = easterly wind Stratospheric polar vortex Winter The stratospheric chemistry stratopause tropopause Pole Equator Pole The stratospheric chemistry stratopause tropopause Pole Summer Equator Winter Pole The stratospheric chemistry stratopause UV O2 O3 tropopause Pole Summer Equator Winter Pole The stratospheric chemistry stratopause UV O3 O2 O O3 tropopause Pole Summer Equator Winter Pole The stratospheric chemistry stratopause UV O3 O3 OH HO2 OH HO2 O3 O2 O O3 O3 O3 OH HO2 Pole Summer tropopause Equator OH HO2 Winter Pole The stratospheric chemistry stratopause UV O3 O3 OH HO2 OH HO2 O3 O3 O NO NO2 NO NO2 O2 O3 O3 O3 OH HO2 Pole Summer O3 tropopause Equator OH HO2 Winter Pole The stratospheric chemistry stratopause UV O3 O3 OH HO2 OH HO2 O3 O3 O NO NO2 NO NO2 O2 O3 Pole Summer O3 Cl ClO O3 O3 OH HO2 O3 tropopause Equator OH HO2 Winter Pole The stratospheric chemistry stratopause UV O3 O3 OH HO2 OH HO2 O3 O3 O NO NO2 NO NO2 O2 O3 O3 Cl ClO O3 O3 OH HO2 O3 tropopause OH HO2 density densité Pole Summer Equator Winter Pole Morphology of the ozone layer Ozone concentration, averaged along parallels, for Dec – Jan – Feb of 1979 (pre- ozone hole period) Altitude (km) 1012 molecules cm-3 Ozone layer How is the Stratosphere Working ? Middle atmosphere: Dynamics/Transport Chemistry Radiation How is the Stratospere Working ? Lower atmosphere: Dynamics/Transport Chemistry Radiation 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 Ozone depletion due to CFCs Ozone column observations (ground-based, WMO 1998) (DU) CFC scenario (A1), tropospheric concentration, (WMO 1998) (DU) 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 Effects of Greenhouse Gases on Ozone Layer ? GHG scenarios, tropospheric concentrations (WMO 2001) (WMO 1998, WMO 2001) CO2 CH4 Animation_2.wmv N2O CFCs Changes in stratospheric ozone between 1979 and 2060? Potential effects of increasing GHGs on stratospheric ozone: Increasing concentrations of greenhouse gases (GHGs) : CO2, N2O, CH4, … (Low concentration of Cly) Chemical effects (mainly due to N2O and CH4) Radiative effects (mainly due to CO2) Dynamical effects (???) Changes in the distribution of stratospheric ozone Changes in the total ozone Chemical and radiative effects for August Total ozone change: Chemical and radiative effects for August Total ozone change: Separated effects of: N2O CO2 Chemical ozone loss increased due to larger N2O concentration Chemical ozone loss slowed down due to temperature decrease Dynamical effects... Potential effects of increasing GHGs on stratospheric ozone: Increasing concentrations of greenhouse gases (GHGs) : CO2, N2O, CH4, … (Low concentration of Cly) Chemical effects (mainly due to N2O and CH4) Radiative effects (mainly due to CO2) Dynamical effects (???) Changes in the distribution of stratospheric ozone Changes in the total ozone Transport, mixing and chemistry 1. Non-linear chemistry in turbulent flows 2. Stratosphere-troposphere exchange Transport, mixing and chemistry Winter Summer WMO, Scientific Assessment of Ozone Depletion: 2002 Transport, mixing and chemistry Instantaneous tropopause (2 PVU from ECMWF data) Climatological tropopause PVU SH NH 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 C concentration A study of non-linear chemistry (A+B→C) in turbulent flows Increasing diffusion, decreasing resolution time 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 Winter Stratosphere tropopause 700 hPa Boundary layer Stratosphere tropopause 700 hPa Boundary layer Calculation based upon ERA15 (1979-1993) 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 & Lean 2006 Solar variability and ozone layer Courtesy: Paul Charbonneau, Universite de Montreal In Summary: Research Focus Research Tools • • • • • • • • • • • • • • Stratosphere Transport and dynamics Chemistry Chemical data assimilation Ozone layer Climate Solar Variability Future satellite mission STEP Research Infrastructure • • Supercomputer Desktop computers General Circulation Models Mesoscale Models Chemistry models Trajectory models Meteorological data (ERA40,…) Satellite data 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 Further information http://www.meteo.mcgill.ca/bourqui http://www.meteo.mcgill.ca/hydroxyl Office: BH 815 Email: [email protected]
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