1. Atmospheric transport and ozone chemistry
Lecture SS 2007
Mark Weber
S4350
Tel
Lecture material of today:

2. Lecture schedule
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

3. Literature
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,
Brasseur, G., and Solomon, S., Aeronomy of the Middle Atmosphere, 3rd ed., Springer, Dordrecht, 2005.

4. 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

5. WMO ozone assessment and Montreal Protocol

6. WMO ozone assessment and Montreal Protocol

7. Important issues in the assessment
Preface WMO O3 Assessment 2006:
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?)

8. Student presentations

9. student presentations about WMO ozone assessment 2006
Select a topic or subsection until May 17 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!

10. IPCC (Intergovernmental Panel on Climate Change)
IPCC Report 2007
IPCC (Intergovernmental Panel on Climate Change)
Fourth Assessment published in February 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)

11. Introduction

12. Only parts are covered in this lecture
Climate and chemistry
Only parts are covered in this lecture
Brasseur et al., 1999

13. Only parts are covered in this lecture
Climate and chemistry
Only parts are covered in this lecture
Introduction:
Stratosphere-troposphere exchange
Distribution and variability of stratospheric ozone
Climate change
Brasseur et al., 1999

14. Troposphere-stratosphere coupling
Source gases are generally long-lived and inert/well-miced in the troposphere. e.g. cfc. Source gas injection is them main path into the straosphere. Intermediate pridcts genearally have shorter life times so that the PGI pathway is rather small (factor of 10 smaller). Examples are hydrogenated cfc.

15. Stratospheric circulation and strat-trop exchange
planetary wave driving by momentum and heat flux transfer from the troposhere
after Holton et al. 1995

16. Chemistry & transport of short-lived species

17. Stratospheric chemistry
Brasseur et al., 1999

18. Tropospheric chemistry
Brasseur et al., 1999
Up to 50% of free tropospheric ozone may be from the stratosphere
Free troposphere ranges from abt. 2 km (above PBL) to the tropopause

19. Annual cycle in total ozone
GOME / ERS II: derives total ozone columns (TOZ) from absorption signals in the backscattered solar radiation

20. Annual cycle in total ozone
Transport (dynamics) and chemistry leads to seasonal ozone variability in tropics, middle and high latitudes
Photochem. summer decay
wave driven
transport
Latitude
Photochem. summer decay
ozone hole (chemical ozone loss)

21. The global picture: middle atmosphere dynamics
Potential temperature: theta=T*(po/p)^kappa, kappa=2/7  adiabatic motion (fairly fast), diabatic motion acrooss PT surfaces are slow and driven by heating (very slow) except in convective systems (tropical troposphere/frontal uplifting).

22. The global picture: middle atmosphere dynamics
ozone production by photochemistry
downward transport of ozone, photochemically stable
photochemical decay
ozone hole, chemical ozone loss
Potential temperature: theta=T*(po/p)^kappa, kappa=2/7  adiabatic motion (fairly fast), diabatic motion acrooss PT surfaces are slow and driven by heating (very slow) except in convective systems (tropical troposphere/frontal uplifting).

23. Annual cycle in total ozone
Transport (dynamics) and chemistry leads to seasonal ozone variability in tropics, middle and high latitudes
Photochem. summer decay
wave driven
transport
Latitude
Photochem. summer decay
ozone hole (chemical ozone loss)

24. Inter-annual ozone variability
Northern polar latitudes spring
63°N-90°N
63°S-90°S
Southern polar latitudes spring
‚ozone hole‘: TOZ < 200 DU

25. Inter-annual ozone variability
inter-hemispheric
differences in transport
63°N-90°N
chemical
ozone loss
63°S-90°S
inter-annual variability in
ozone chemistry & transport
in each hemisphere

26. Ozone hole and polar vortex, southern hemisphere
GOME total ozone above Antarctica
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)

27. Ozone variability in northern hemisphere

28. High inter-annual ozone variability in winter/spring NH
Cold (stratospheric) Arctic winters with low ozone:
1996, 1997, 2000, (2003), 2005
Warm Arctic winters with high ozone
1998, 1999, 2001, 2002, 2004

29. Polar stratospheric temperature anomalies
Correlation of stratospheric temperatures and polar ozone, e.g. low temperatures and low ozone
analysis data
satellite data
radiosondes
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

30. Height resolved ozone from GOME
8-15 km
15-23 km
23-30 km
ozone inside polar vortex
„dynamics and chemistry“
Ozone minihole
„dynamics“
Eichmann et al. 1999

31. Transport and changes in chemical composition
Geopotential height in dekameter at 300 hPa (ca. 9 km altitude)
Transport and chemical composition: subtropical streamer (high tropopause) in NH mid latitudes
low ozone above Europe (mini-hole)

32. 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
NAO is a signature of the tropospheric pattern (called Arctic oscillation). It is also sometimes called a climate pattern and had a significant impact on ocean /signature in ice cores.

33. Climate change: evolution of greenhouse gases
Note today:
[CO2]  370 ppmv
[CH4]  1700 ppbv
IPCC 2001

34. Climate change: evolution of greenhouse gases
Note today:
[CO2]  370 ppmv
[CH4]  1700 ppbv
Mouna Loa Hawaii
Ahrens 1999

35. Can we learn from the past?
Note today:
[CO2]  370 ppmv
[CH4]  1700 ppbv
Age in kyears

36. Surface temperature from the past to the future
Mann et al, 1998
Cubash
Mann et al., 1998: temperature proxy data
ECHO-G1: climate model result

37. Relationship between climate elements
heat flux from
ocean
solar radiation
energy budget
temperature
wind, cloud, precipitation,
atmospheric waves
topography,
geography
Impact on
trace gases
chemistry
transport
atmosphere
human activities, natural emission,
volcanism
soil composition,
vegetation, albedo

38. turbulence, lightning, tornadoes < 100 km micro
Atmospheric scales
turbulence, lightning, tornadoes
< 100 km
micro
mountain winds, foehn, hurricanes
~100 km
regional
sea wind circulation, frontal systems,
gravity waves
<1000 km
mesoscale
cyclonic waves
planetary waves
global, > 1000km
Synoptic
phenomenas
scale
terminology

39. stratosphere troposphere Atmospheric scales
turbulence, lightning, tornadoes
< 100 km
micro
mountain winds, foehn, hurricanes
~100 km
regional
sea wind circulation, frontal systems,
gravity waves
<1000 km
mesoscale
cyclonic waves
planetary waves
global, > 1000km
Synoptic
phenomenas
scale
terminology
stratosphere
troposphere

40. Atmospheric space and time scales
Warneke 1997
spatial scale
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

41. Chemical time scales

42. 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 also depend on climate changes
Global
warming
pytoplancton
destruction
CFCs
deforrestation
tropospheric
ozone formation
emissions
equivalent effective
stratospheric chlorine
(EESC)
stratospheric
ozone depletion
modification of
tropospheric
chemistry