i/1 atmospheric transport and ozone chemistry lecture ss 2008 mark weber s4350 tel. -2362...
TRANSCRIPT
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Atmospheric transport and ozone chemistry
Lecture SS 2008
Mark Weber S4350 Tel. -2362 [email protected]
Lecture material of today: www.iup.uni-bremen.de/~weber/vorlesung_ss08
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Introduction (today)
Atmospheric dynamics
Radiative transfer, heating, and vertical transport
Trace gases
General middle atmospheric chemistry
Ozone chemistry and catalytic cycles
Heterogeneous chemistry, stratospheric particles, and the ozone hole
The tropical tropopause
Solar (decadal) variability and dynamical coupling
Greenhouse gasses and climate-chemistry interaction
Lecture schedule
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Andrews, D. G., J. R. Holton, and C.B. Leovy, Middle Atmosphere Dynamics, Academic Press, Orlando, 1990.
Holton, J. R., An Introduction to Dynamic Meteorology, 3rd ed., Academic Press, San Diego, 1992.
Brasseur G., et al., Atmospheric Chemistry and Global Change, Oxford University Press, Oxford, 1999.
Seinfeld, J. H., Pandis, S. N., Atmospheric Chemistry and Physics – From Air Pollution to Climate Change, John Wiley & Sons, New York, 1998.
Wayne, R. P., Chemistry of Atmospheres, 3rd Ed., Clarendon Press, Oxford, 2003.
Brasseur, G., and Solomon, S., Aeronomy of the Middle Atmosphere, 3rd ed., Springer, Dordrecht, 2005.
Literature
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student presentations about WMO ozone assessment 2006
Summary of selected chapters/sections from WMO Scientific Assessment of Ozone Depletion 2006
15 minute presentations at the end of the semester
http://www.wmo.ch/web/arep/reports/ozone_2006/ozone_asst_report.html
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WMO ozone assessment and Montreal Protocol
www.iup.uni-bremen.de/~weber/WMO2006/
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WMO ozone assessment and Montreal Protocol
www.iup.uni-bremen.de/~weber/WMO2006/
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Important issues in the assessment
•ozone recovery expected from leveling off of stratospheric chlorine (Montreal Protocol and ammendments), but role of stratospheric bromine/shortlived substances may become more important
•How does climate change affect the ozone layer (Antarctic ozone hole anomaly in 2002? changes in atmpospheric transport and chemistry?)
Preface WMO O3 Assessment 2006:
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Student presentations
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student presentations about WMO ozone assessment 2006
•Select a topic or subsection until May 8 after personal consultation in my office•Presentation shall be brief, just
– summarise important findings (scientific summary in the beginnning of each chapter) supported by figures from the chapters
– discuss open scientific questions
– no more than 8-10 viewgraphs per presentations!
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IPCC Report 2007
•IPCC assessment– climate impacts from changes in greenhouse gases, note: O3 is (but a minor) greenhouse
gas– major focus: (surface) temperature, hydrological cycle (precipitation, ice sheets)
•IPCC (Intergovernmental Panel on Climate Change)•Fourth Assessment published in February 2007
http://ipcc-wg1.ucar.edu/wg1/wg1-report.html
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I.Introduction
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Climate and chemistry
Brasseur et al., 1999
Only parts are covered in this lecture
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Climate and chemistry
Brasseur et al., 1999
Only parts are covered in this lecture
Introduction:
• Stratosphere-troposphere exchange
• Distribution and variability of stratospheric ozone
• Climate change
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Troposphere-stratosphere coupling
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Stratospheric circulation and strat-trop exchange
after Holton et al. 1995
planetary wave driving by momentum and heat flux transfer from the troposhere
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Chemistry & transport of short-lived species
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Stratospheric chemistry
Brasseur et al., 1999
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Tropospheric chemistry
Up to 50% of free tropospheric ozone may be from the stratosphere Free troposphere ranges from abt. 2 km (above planetary boundary layer)
to the tropopause
Brasseur et al., 1999
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Annual cycle in total ozone
GOME / ERS II: derives total ozone columns (TOZ) from absorption signals in the backscattered UV solar radiation
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wave driventransport
Photochem. summer decay
Photochem. summer decay
ozone hole (chemical ozone loss)
Annual cycle in total ozone
Transport (dynamics) and chemistry leads to seasonal ozone variability in tropics, middle and high latitudes
Lati
tude
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The global picture: middle atmosphere dynamics
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The global picture: middle atmosphere dynamics
ozone production by photochemistry
downward transport of ozone, photochemically stable
photochemical decayozone hole, chemical
ozone loss
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Inter-annual ozone variability
63°N-90°N
63°S-90°S
Northern polar latitudes spring
Southern polar latitudes spring
‚ozone hole‘: TOZ < 200 DU
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Inter-annual ozone variability
63°N-90°N
63°S-90°S
chemical ozone loss
inter-hemispheric differences in transport
inter-annual variability in ozone chemistry & transportin each hemisphere
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Ozone hole and polar vortex, southern hemisphere
GOME total ozone above Antarctica 1996-2002 Low inter-annual ozone variability in SH winter/spring
cold Antarctic stratospheric winters with low ozone („hole“) and large polar vortex every year
exception 2002, rather warm with higher ozone, but 2003 and 2004 are cold again like before (not shown)
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Ozone hole and polar vortex, southern hemisphere
GOME/SCIAMACHY October total ozone above Antarctica 1996-2006 Low inter-annual ozone variability in SH winter/spring
cold Antarctic stratospheric winters with low ozone („hole“) and large polar vortex every year
exception 2002, rather warm with higher ozone.
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Ozone variability in northern hemisphere
63°N-90°N
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Ozone variability
High inter-annual ozone variability in winter/spring NHCold (stratospheric) Arctic winters with low ozone:
1996, 1997, 2000, (2003), 2005Warm Arctic winters with high ozone
1998, 1999, 2001, 2002, 2004
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Polar stratospheric temperature anomalies
Correlation of stratospheric temperatures and polar ozone, e.g. low temperatures and low ozone
analysis datasatellite dataradiosondes
Note: here are anomalies shown (differences to long-term mean)
Polar stratospheric T are lower in SH winter than in NH winter (about 15 K)
50 hPa/ ca. 18 km altitude
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15-23 km8-15 km 23-30 km
Ozone minihole„dynamics“
ozone inside polar vortex„dynamics and chemistry“
Eichmann et al. 1999
Height resolved ozone from GOME
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Transport and changes in chemical composition
Transport and chemical composition: subtropical streamer (high tropopause) in NH mid latitudes
low ozone above Europe (mini-hole)
Geopotential height in dekameter at 300 hPa (ca. 9 km altitude)
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Tropospheric weather patterns and stratospheric ozone
North Atlantic Oscillation (NAO) is the normalised (surface) pressure difference between Lisbon (Portugal) and Stykkisholmur (Island) for the winter months December-March
Connection between tropospheric weather patterns (surface) and stratospheric ozone (~22 km altitude)
90% of ozone in stratosphere total ozone mainly stratospheric ozone
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Climate change: evolution of greenhouse gases
Note today:
[CO2] 380 ppmv
[CH4] 1700 ppbv
IPCC 2001
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Climate change: evolution of greenhouse gases
Note today:
[CO2] 380 ppmv
[CH4] 1700 ppbv
Mouna Loa Hawaii
Ahrens 1999
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Climate change: evolution of greenhouse gases
Note today:
[CO2] 380 ppmv
[CH4] 1700 ppbv
Buchwitz et al., 2007
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Can we learn from the past?
Note today:
[CO2] 380 ppmv
[CH4] 1700 ppbv
Age in kyears
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Surface temperature from the past to the future
Mann et al, 1998
Mann et al., 1998: temperature proxy dataECHO-G1: climate model result
Cubash
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Relationship between climate elements
energy budget
temperature
wind, cloud, precipitation,atmospheric waves &
circulation
atm
os
ph
ere
solar radiationheat flux from
ocean
topography,
geography
soil composition,
vegetation, albedo
human activities, natural emission,volcanism
Impact ontrace gaseschemistrytransport
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Atmospheric scales
turbulence, lightning, tornadoes
< 100 kmmicro
mountain winds, foehn, hurricanes
~100 kmregional
sea wind circulation, frontal systems,gravity waves
<1000 kmmesoscale
cyclonic wavesplanetary waves
global, > 1000kmSynoptic
phenomenasscaleterminology
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Atmospheric scales
turbulence, lightning, tornadoes
< 100 kmmicro
mountain winds, foehn, hurricanes
~100 kmregional
sea wind circulation, frontal systems,gravity waves
<1000 kmmesoscale
cyclonic wavesplanetary waves
global, > 1000kmSynoptic
phenomenasscaleterminology
troposphere
stratosphere
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Atmospheric space and time scales
Glossary: planetarische Wellen=planetary scale waves, Wolken Cluster=cloud cluster, kleinräumige Turbulenz= small scale turbulence, Schwerewellen=gravity waves, Schallwellen=sound waves, kleinräumig=micro scale, grossräumig=synoptic
tim
e s
cale
spatial scale
Warn
eke 1
99
7
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Chemical time scales
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Chemical composition and global change
What causes the large chemical ozone depletion in SH spring?
High stratospheric chlorine (halogen) loading from CFC emissions
Cold temperatures inside the polar vortex
However, past and future stratospheric temperatures depend on climate changes
Globalwarming
emissions
deforrestation
pytoplanctondestruction
troposphericozone formation
stratospheric ozone depletion
modification of tropospheric chemistry
CFCs
equivalent effective stratospheric chlorine
(EESC)