Atmospheric transport and ozone chemistry Lecture SS 2008 Mark Weber S4350 Tel. -2362

1. Atmospheric transport and ozone chemistry Lecture SS 2008 Mark Weber S4350 Tel. -2362 weber@uni-bremen.de Lecture material of today: www.iup.uni-bremen.de/~weber/vorlesung_ss08

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, 2003. 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 • http://www.wmo.ch/web/arep/reports/ozone_2006/ozone_asst_report.html

5. WMO ozone assessment and Montreal Protocol • www.iup.uni-bremen.de/~weber/WMO2006/

6. WMO ozone assessment and Montreal Protocol • www.iup.uni-bremen.de/~weber/WMO2006/

7. 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:

8. Student presentations

9. 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!

10. 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

11. Introduction

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

13. 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

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 • 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

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

22. The global picture: middle atmosphere dynamics ozone production by photochemistry downward transport of ozone, photochemically stable photochemical decay ozone hole, chemical ozone loss

23. 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

24. 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

25. Ozone hole and polar vortex, southern hemisphere • GOME total ozone above Antarctica 1996-2002 • Low inter-annual ozone variability in SH winter/spring • coldAntarctic 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)

26. 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 • coldAntarctic stratospheric winters with low ozone („hole“) and large polar vortex every year • exception 2002, rather warm with higher ozone.

27. Ozone variability in northern hemisphere • 63°N-90°N

28. Ozone variability • 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 23-30 km 8-15 km 15-23 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

33. Climate change: evolution of greenhouse gases • Note today: • [CO2] 380 ppmv • [CH4]  1700 ppbv IPCC 2001

34. Climate change: evolution of greenhouse gases • Note today: • [CO2] 380 ppmv • [CH4]  1700 ppbv Mouna Loa Hawaii Ahrens 1999

35. Climate change: evolution of greenhouse gases • Note today: • [CO2] 380 ppmv • [CH4]  1700 ppbv Buchwitz et al., 2007

36. Can we learn from the past? • Note today: • [CO2] 380 ppmv • [CH4]  1700 ppbv Age in kyears

37. 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

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

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

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

41. Atmospheric space and time scales time scale 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

42. Chemical time scales

43. 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 Global warming pytoplancton destruction deforrestation CFCs tropospheric ozone formation emissions equivalent effective stratospheric chlorine (EESC) modification of tropospheric chemistry stratospheric ozone depletion