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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. Lecture schedule. Introduction (today) Atmospheric dynamics

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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


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


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.


Student presentations about wmo ozone assessment 2006
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


Wmo ozone assessment and montreal protocol
WMO ozone assessment and Montreal Protocol

  • www.iup.uni-bremen.de/~weber/WMO2006/


Wmo ozone assessment and montreal protocol1
WMO ozone assessment and Montreal Protocol

  • www.iup.uni-bremen.de/~weber/WMO2006/


Important issues in the assessment
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:



Student presentations about wmo ozone assessment 20061
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!


Ipcc report 2007
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



Climate and chemistry
Climate and chemistry

  • Only parts are covered in this lecture

Brasseur et al., 1999


Climate and chemistry1
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



Stratospheric circulation and strat trop exchange
Stratospheric circulation and strat-trop exchange

planetary wave driving by momentum and heat flux transfer from the troposhere

  • after Holton et al. 1995



Stratospheric chemistry
Stratospheric chemistry

Brasseur et al., 1999


Tropospheric chemistry
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


Annual cycle in total ozone

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


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)



The global picture middle atmosphere dynamics1
The global picture: middle atmosphere dynamics

ozone production by photochemistry

downward transport of ozone, photochemically stable

photochemical decay

ozone hole, chemical ozone loss


Inter annual ozone variability
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


Inter annual ozone variability1
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


Ozone hole and polar vortex southern hemisphere
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)


Ozone hole and polar vortex southern hemisphere1
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.



Ozone variability
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


Polar stratospheric temperature anomalies
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


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


Transport and changes in chemical composition
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)


Tropospheric weather patterns and stratospheric ozone
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


C limate change evolution of greenhouse gases
Climate change: evolution of greenhouse gases

  • Note today:

  • [CO2] 380 ppmv

  • [CH4]  1700 ppbv

IPCC 2001


C limate change evolution of greenhouse gases1
Climate change: evolution of greenhouse gases

  • Note today:

  • [CO2] 380 ppmv

  • [CH4]  1700 ppbv

Mouna Loa Hawaii

Ahrens 1999


C limate change evolution of greenhouse gases2
Climate change: evolution of greenhouse gases

  • Note today:

  • [CO2] 380 ppmv

  • [CH4]  1700 ppbv

Buchwitz et al., 2007


Can we learn from the past
Can we learn from the past?

  • Note today:

  • [CO2] 380 ppmv

  • [CH4]  1700 ppbv

Age in kyears


Surface temper a tur e from the past to the future
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


Relationship between climate elements
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


Atmospheric scales
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


Atmospheric scales1
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


Atmospheric space and time scales
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



Chemical composition and global change
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


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