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Introduction to Environmental Earth ScienceIntroduction to Environmental Earth Science
Stratospheric Ozone DepletionStratospheric Ozone Depletion
July 24, 2007July 24, 2007
Environmental ScienceEnvironmental Science
Fumio Fumio HasebeHasebe
Stratospheric Ozone DepletionStratospheric Ozone Depletion
1.1. The Ozone LayerThe Ozone Layer
Structure of the AtmosphereStructure of the Atmosphere
Stratospheric OzoneStratospheric Ozone
Stratospheric Ozone TransportStratospheric Ozone Transport
2.2. Antarctic Ozone HoleAntarctic Ozone Hole
Mechanism of Ozone HoleMechanism of Ozone Hole
Long-term changesLong-term changes
Temperature ProfileTemperature Profile
US Standard Atmosphere
Troposphere Troposphere vs vs StratosphereStratosphere
Composite Section of Temperature & WindComposite Section of Temperature & Wind
Ozone & Temperature ProfilesOzone & Temperature Profiles
Ozone Layer
Ozone Layer
Troposphere
Troposphere
Stratosphere
Stratosphere
Absorption of Solar RadiationAbsorption of Solar Radiation
UV-B
Skin CancerSkin Cancer Terrestrial EvolutionTerrestrial Evolution
!! Outgassing Outgassing to form secondary atmosphere & oceanto form secondary atmosphere & ocean
!! Absorption of volcanic gas by the oceanAbsorption of volcanic gas by the ocean
!! Neutralization of the ocean by Neutralization of the ocean by crustal crustal metalsmetals
!! Absorption of COAbsorption of CO22 by the ocean by the ocean
!! Formation of life in the oceanFormation of life in the ocean
–– Fixing of carbon (shell --> limestone)Fixing of carbon (shell --> limestone)
–– Release of oxygen (photosynthesis)Release of oxygen (photosynthesis)
!! Formation of the ozone layerFormation of the ozone layer
–– Shield from UV-B (protection for life)Shield from UV-B (protection for life)
!! Expansion of biosphere to land surfaceExpansion of biosphere to land surface
Balance among atmosphere-ocean-biosphereBalance among atmosphere-ocean-biosphere
Positive feedbackPositive feedback
Classical TheoryClassical Theory
!! Ozone synthesis by atomic & molecular oxygenOzone synthesis by atomic & molecular oxygen
!! Energy transform from radiation to heatEnergy transform from radiation to heat
Chapman Reactions
Dominant Processes for OzoneDominant Processes for Ozone
Upper Stratosphere:
Lower Stratosphere:
Atmospheric Transport
Ozone and the General CirculationOzone and the General Circulation
Seasonal Variation of Total OzoneSeasonal Variation of Total Ozone
Min
Max
Max
Min
Ozone Destroying ReactionsOzone Destroying Reactions Ozone Destroying ReactionsOzone Destroying Reactions
Hydrogen Oxides
Nitrogen Oxides
Chlorine Oxides
Watson et al. (1986)
Anthropogenic Ozone DestructionAnthropogenic Ozone Destruction
Nature, 249, 1974
Chlorofluorocarbon (CFC)Chlorofluorocarbon (CFC)Chlorofluorocarbon (CFC)Chlorofluorocarbon (CFC)
Farman et al.(1985)
Evidence of Antarctic Ozone LossEvidence of Antarctic Ozone Loss
Total Ozone Potential Vorticity
Polar Vortex
Dynamical Field of the Ozone HoleDynamical Field of the Ozone Hole Vertical Ozone ProfilesVertical Ozone Profiles
Ozone Loss
Characteristic FeaturesCharacteristic Features
!! Ozone hole boundary corresponding to polar vortex edgeOzone hole boundary corresponding to polar vortex edge
!! ClO ClO accumulation in the vortex prior to ozone hole formationaccumulation in the vortex prior to ozone hole formation
ozone
loss
accumulation
boundary
Anderson et al. (1991)
accumulation
!! Cooling of polar night lower stratosphereCooling of polar night lower stratosphere
!! Formation of polar night jet/polar vortexFormation of polar night jet/polar vortex
!! Condensation of polar stratospheric cloud (PSC)Condensation of polar stratospheric cloud (PSC)
!! Photodissociation Photodissociation to release to release Cl Cl on sunlight returnon sunlight return
!! Chlorine-catalyzed OChlorine-catalyzed O33 destruction destruction
!! Heterogeneous reactions on the PSC surfaceHeterogeneous reactions on the PSC surface
Why So Much Why So Much ClO ClO in Ozone Hole?in Ozone Hole? Polar Ozone Depletion in SpringPolar Ozone Depletion in Spring
WMO
(2007)
Polar Ozone Depletion in SpringPolar Ozone Depletion in Spring
WMO
(2007)
Stability of the Polar VortexStability of the Polar Vortex
Yoden et al. (2002)
SummarySummary
!! Structure of the AtmosphereStructure of the Atmosphere–– Troposphere and StratosphereTroposphere and Stratosphere
–– Stratospheric Ozone LayerStratospheric Ozone Layer
!! Stratospheric OzoneStratospheric Ozone–– Absorption of Solar UV RadiationAbsorption of Solar UV Radiation
–– Protection of Life on EarthProtection of Life on Earth
–– Classical Ozone ChemistryClassical Ozone Chemistry
–– Dynamical Control in the Lower StratosphereDynamical Control in the Lower Stratosphere
!! Catalytic Ozone DestructionCatalytic Ozone Destruction–– Hydrogen, Nitrogen, Chlorine OxidesHydrogen, Nitrogen, Chlorine Oxides
–– Accumulation of Chlorine Reservoir Released from CFCAccumulation of Chlorine Reservoir Released from CFC
!! Discovery of the Antarctic Ozone HoleDiscovery of the Antarctic Ozone Hole–– Unexpected Huge Ozone Loss in the Antarctic SpringUnexpected Huge Ozone Loss in the Antarctic Spring
!! Mechanism of Ozone HoleMechanism of Ozone Hole–– Formation of PSC in the Cold Polar VortexFormation of PSC in the Cold Polar Vortex
–– Activation of Chlorine by Heterogeneous ReactionsActivation of Chlorine by Heterogeneous Reactions
!! Long-Term ChangesLong-Term Changes–– Long Lasting Monitoring is RequiredLong Lasting Monitoring is Required