Atmospheric Chemistry and Climate

1
A multi-model analysis of the tropospheric
ozone budgetDavid Stevenson1, F.J. Dentener2,
M.G. Schultz3, K. Ellingsen4, T.P.C. van Noije5,
O. Wild6, G. Zeng7, M. Amann8, C.S. Atherton9, N.
Bell10, D.J. Bergmann9, I. Bey11, T. Butler12,
J. Cofala8, W.J. Collins13, R.G. Derwent14, R.M.
Doherty1, J. Drevet11, H.J. Eskes5, A.M.
Fiore15, M. Gauss4, D.A. Hauglustaine16, L.W.
Horowitz15, I.S.A. Isaksen4, M.C. Krol2, J.-F.
Lamarque17, M.G. Lawrence12, V. Montanaro18,
J.-F. Müller19, G. Pitari18, M.J. Prather20,
J.A. Pyle7, S. Rast3, J.M. Rodriguez21, M.G.
Sanderson13, N.H. Savage7, D.T. Shindell10, S.E.
Strahan21, K. Sudo6, and S. Szopa16 1.
University of Edinburgh, School of GeoSciences,
Edinburgh, United Kingdom. 2. Joint Research
Centre, Institute for Environment and
Sustainability, Ispra, Italy. 3. Max Planck
Institute for Meteorology, Hamburg, Germany. 4.
University of Oslo, Department of Geosciences,
Oslo, Norway. 5. Royal Netherlands
Meteorological Institute (KNMI), Atmospheric
Composition Research, De Bilt, the Netherlands.
6. Frontier Research Center for Global Change,
JAMSTEC, Yokohama, Japan. 7. University of
Cambridge, Centre of Atmospheric Science, United
Kingdom. 8. IIASA, International Institute for
Applied Systems Analysis, Laxenburg, Austria. 9.
Lawrence Livermore National Laboratory, Atmos.
Science Div., Livermore, USA. 10. NASA-Goddard
Institute for Space Studies, New York, USA. 11.
Ecole Polytechnique Fédéral de Lausanne (EPFL),
Switzerland. 12. Max Planck Institute for
Chemistry, Mainz, Germany. 13. Met Office,
Exeter, United Kingdom. 14. rdscientific,
Newbury, UK. 15. NOAA GFDL, Princeton, NJ, USA.
16. Laboratoire des Sciences du Climat et de
l'Environnement, Gif-sur-Yvette, France. 17.
National Center of Atmospheric Research,
Atmospheric Chemistry Division, Boulder, CO, USA.
18. Università L'Aquila, Dipartimento di Fisica,
L'Aquila, Italy. 19. Belgian Institute for Space
Aeronomy, Brussels, Belgium. 20. Department of
Earth System Science, University of California,
Irvine, USA 21. Goddard Earth Science
Technology Center (GEST), Maryland, Washington,
DC, USA.
2
Tropospheric ozone budget

• Ozone is an important greenhouse gas and air
  pollutant
• Ozone budget and lifetime crucial for
• Long-range transport
• Global Warming Potentials
• Oxidising capacity
• Climate-Chemistry (radiative forcing and
  feedbacks)
• Previous intercomparisons (e.g. IPCC TAR
  literature survey) of modelled tropospheric ozone
  budget hampered by
• Definition of PO3 and LO3
• Definition of troposphere
• Differences in emissions
• What we really want to understand are differences
  due to model formulation (chemistry, convection,
  resolution, mixing, boundary conditions)

3
Defining the O3 or Ox budget
O3O(3P) O(1D)
Different model chemical schemes potential
source of differences
4
ACCENT Intercomparison

• Prescribed anthropogenic emissions
• but modellers used their own natural emissions,
  so still some emissions uncertainty
• Defined O3 budget terms
• but some modellers used their own definitions,
  specific to chemical scheme
• requested 3D monthly mean P and L
• also O3 deposition inferred stratospheric input
• Defined tropopause O3150 ppbv
• centralised analysis

5
20 Models supplied O3 budgets

• CHASER_CTM
• CHASER_GCM
• FRSGC/UCI
• GEOS-CHEM
• GMI/CCM3
• GMI/DAO
• GMI/GISS
• LLNL-IMPACT
• LMDz/INCA-CTM
• LMDz/INCA-GCM

• MOZ2-GFDL
• MOZART4
• MOZECH
• MOZECH2
• STOCHEM-HadAM3
• STOCHEM-HadGEM
• TM4
• TM5
• ULAQ
• UM_CAM

CTMs driven by analyses
CTMs coupled to GCMs
CTMs driven by GCM output
6
Year 2000 Tropospheric O3 budget
Tg(O3)/yr P L D Sinf B/Tg(O3) t/days
ACCENT 5100 4670 1000 550 340 22
IPCC TAR 3420 3470 770 770 300 24
7
Zonal Annual Mean Ozone chemical production
Ozonechemical productionmainly reflectsNOx
distributions
8
Zonal Annual Mean Ozone chemical destruction
Ozonechemical destructionmainly reflectsH2O
distribution (also O3 distribution)
9
Zonal Annual Mean Ozone net chemical production
10
Surface level O3 Net Chemical Production
11
Multi-model ensemble mean ozone P, L, NCP
Ship NOx
? 0.997
Surface
12
Multi-model ensemble mean ozone P, L, NCP
? 0.975
13
Multi-model ensemble mean ozone P, L, NCP
? 0.930
14
Multi-model ensemble mean ozone P, L, NCP
? 0.870
15
Multi-model ensemble mean ozone P, L, NCP
Mid-tropnet destruction
? 0.792
16
Multi-model ensemble mean ozone P, L, NCP
Mid-tropnet destruction
? 0.700
17
Multi-model ensemble mean ozone P, L, NCP
Mid-tropnet destruction
? 0.600
18
Multi-model ensemble mean ozone P, L, NCP
? 0.505
19
Multi-model ensemble mean ozone P, L, NCP
? 0.422
20
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.355
21
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.300
22
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.250
23
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.200
24
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.150
25
Multi-model ensemble mean ozone P, L, NCP
Upper-tropnet productionlightning
? 0.099
26
Global O3 budget terms
Colours signifydifferent models
O3 lifetime / days
Ensemble mean model (offset)
O3 burden / Tg(O3)
27
Conclusions

• First well-constrained analysis of several
  models ozone budgets, with consistent
  definitions of budget terms, tropospheric domain,
  and anthropogenic emissions
• Broadly consistent gross features
• Production reflects NOx distribution
• Destruction reflects H2O (and O3) distribution
• Some inter-model differences in lightning
  NOx/convection isoprene H2O polewards
  transport BL
• Quite large differences compared to IPCC TAR
• NOx and isoprene emissions
• Stratospheric input
• Deposition also crucial most of the O3 budget is
  in BL

28
Further information

• Dentener et al., in press, Env. Sci. Tech.
• Overview of intercomparison
• Stevenson et al., in press, JGR
• Tropospheric O3 and CH4
• Van Noije et al., in press, ACPD
• NO2 columns, modelled GOME
• Shindell et al., submitted, JGR
• CO, modelled MOPITT
• Dentener et al., submitted, GBC
• Deposition of N and S
• Ellingsen et al., in prep.
• Surface O3 air quality
• probably more
• dstevens_at_staffmail.ed.ac.uk