|
(A) Proposed simulations within CCMVal in the near term
(B) Reproducing the past: Forcings for a transient model simulation 1960 to present da
(C) Making predictions: Forcings for a transient model simulation from present day to 2100
(D) Model recommendations concerning the model set-up and the variables that should be stored in order to allow sophisticated inter-comparisons of chemistry, transport, dynamics and radiation in CCMs
(E) Current coupled chemistry-climate models(F) References
(G) Use of CCM results in the upcoming WMO/UNEP Scientific Assessment of Ozone Depletion
In addition to existing CCM simulations, the model results from the REF1, REF2, SCN1, and SCN2 simulations are planned to feature prominently in the 2006 WMO/UNEP ozone assessment. The runs into the future (REF2 and SCN2) will provide the basis for Chapter 6 of the assessment entitled ‘The ozone layer in the 21st century’. This chapter will also validate all 4 CCMVal model runs through historical (1980 or earlier to 2004) intercomparisons with observed ozone changes taken from Chapters 3 and 4 of the assessment. Chapter 5 of the assessment entitled ‘Climate-Ozone Connections’ will also make use of all 4 model simulations as illustrative case studies of the interactions between ozone and climate. The lead authors of these two chapters (Martin Dameris and Mark Baldwin for Chapter 5, Greg Bodeker and Darryn Waugh for Chapter 6) therefore strongly encourage the CCMVal community to submit the requested models data to allow a more detailed assessment of the evolution of total ozone as soon as possible so that they can be used in the assessment. Download CCMVal Ozone Data Request
(H) Model intercomparison A more detailed inter-comparison of CCM results and observations has successfully started. Model results from 10 European model groups that are participating in the European Integrated Project SCOUT-O3 and one model group from outside Europe (CCSR/NIES) have been obtained. The first phase of the inter-comparison will be based on existing runs. With the exception of total column ozone, only transient model simulations for the time period 1980 to 1999 will be compared (no time sliceexperiments). We would like to encourage other model groups to join in the inter-comparison and to send data. Please follow this link for data requests and formats.
(A) Proposed CCMVal
Simulations |
Some of the
key questions
that have been
addressed by the WMO/UNEP
Steering
Committee are: (1) How well do we understand
the past
changes in stratospheric ozone (polar and extra-polar) over the past
few
decades in an environment where stratospheric constituents (including
halogens,
nitrogen oxides, water, and methane) were changing, as was the climate
in this
region? (2) What does our best understanding of the climate and
halogens, as
well as the changing stratospheric composition, portend for the future?
(3) Given
this understanding,
what options do we have for influencing the
future state of the stratospheric ozone layer?
In order
to address
question (1) and (2),
we would propose the following two reference simulations:
REF 1: REPRODUCING THE
PAST, Core time period 1980
to 2000
REF
1
is designed to
reproduce the
well-observed period of the last 25 years during which ozone depletion
is well
recorded, and allows a more detailed investigation of the role of
natural
variability and other atmospheric changes important for ozone balance
and
trends. This transient simulation
includes all anthropogenic and
natural forcings based on changes in trace gases, solar variability,
volcanic
eruptions, quasi-biennial oscillation (QBO), and sea surface
temperatures (SSTs).
SSTs in this run are based on observations. Depending on computer
resources
some model groups might be able to start earlier. We highly recommend
reporting
results for REF1 between 1960 and 2004 to examine model variability.
Forcings
for the simulation and a detailed description can be downloaded from
the CCMVal
website (http://www.pa.op.dlr.de/CCMVal/Forcings/CCMVal_Forcings.html).
They are defined for the time period 1950 to 2004.
SSTs
in REF1 are prescribed as monthly means following the global sea ice
and sea
surface temperature (HadISST1) data set provided by the UK Met Office
Hadley
Centre (Rayner et al., 2003). This
data set is based on blended satellite and in situ observations.
Both
chemical and direct radiative effects of enhanced stratospheric aerosol
abundance from large volcanic eruptions are considered in REF1. The
three major
volcanic eruptions (Agung, 1963; El Chichon, 1982; Pinatubo, 1991) are
taken
into account, i.e., additional heating rates and sulfate aerosol
densities are
prescribed on the basis of model estimates and measurements,
respectively. A
climatology of sulfate surface area density (SAD) based on monthly
zonal means
derived from various satellite data sets between 1979 and 1999 has been
provided by David Considine (
The QBO is
generally described
by
zonal wind profiles measured at the equator. While the QBO is an
internal mode
of atmospheric variability and not a “forcing” in the usual sense, at
the
present time most models do not exhibit a QBO. This leads to an
underestimation
of ozone variability, and compromises the comparison with observations.
While
some of the models
internally generate a QBO, for the others it has been agreed to
assimilate
observed tropical winds. Assimilation of the zonal wind in the QBO
domain can
add the QBO to the system, thus providing for example its effects on
transport
and chemistry. Radiosonde data from Canton Island
(1953-1967), Gan/Maledives (1967-1975) and
The
influence of the 11-year
solar cycle
on photolysis rates is parameterized according to the intensity of the
10.7 cm
radiation of the sun (which is a proxy to the phase of the given solar
cycle).
The spectral distribution of changes in the observed extra-terrestrial
flux is
based on investigations presented by Lean et al. (1997) (see
http://www.drao.nrc.ca/icarus/www/sol_home.shtml
for details).
Recommendation:
We recommend reporting results for
REF1 between 1960 and 2004 to
examine model variability. We will be conducting detailed
model evaluation with data between 1980 and 2004 (i.e., during the
satellite measurement period). Please check the list of model
recommendations that is specified under (D). We encourage groups to run
ensembles.
REF 2 is an internally consistent simulation from the past into the future. The proposed transient simulation uses the IPCC SRES scenario A1B(medium) (IPCC, 2000). REF 2 only includes anthropogenic forcings; natural forcings such as solar variability are not considered, and the QBO is not externally forced (neither in the past, nor in the future). Sulfate surface area density is consistent with REF1 through 1999. Sulfate surface area densities beyond 1999 will be fixed at 1999 conditions (volcanically clean conditions). Changes in halogens will be prescribed following the Ab scenario (WMO, 2003; Table 4B-2). SSTs in this run are based on coupled atmosphere-ocean model-derived SSTs. Depending on computer resources some model groups might be able to run longer and/or start earlier. We recommend reporting results for REF2 until 2050. The forcings on the website are defined through 2100.
Fully coupled atmosphere-ocean CCMs that extend to the middle atmosphere and include coupled chemistry, will use their internally calculated SSTs. CCMs driven by SSTs and sea ice distributions from the underlying IPCC coupled-ocean model simulation could use the model consistent SSTs. One constraint is to make the SST dataset consistent with the SRES greenhouse gas (GHG) scenario A1B(medium). All other CCM groups will run with the same SSTs, provided by a single IPCC coupled-ocean model simulation. These simulations have good spatial resolution, so the data-sets should be suitable for all the CCMs participating in the WMO/UNEP assessment.
Recommendation: We encourage groups to run ensembles.
Sensitivity
experiments :
SCN 1 (REF 1 with enhanced
BrOy): An additional
simulation is being developed to represent the known
lower stratospheric deficit in modeled inorganic bromine abundance.
This
simulation will be identical to REF 1, with the exception of including
source
gases abundances that will increase the burden of BrOy.
A detailed description of SCN1 can be found here --> DOWNLOAD
pdf-file (Contact
for
questions: Ross Salawitch).
SCN 2 (REF 2 with natural
forcings): A
sensitivity simulation defined similar to REF1, with the inclusion of
solar
variability, volcanic activity, and the QBO in the past. Future
forcings will
include a repeating solar cycle and QBO, under volcanic clean aerosol
conditions. SSTs will be based on REF2.
Scenario |
Period |
Trace Gases |
Halogens |
SSTs |
Background
& Volcanic Aerosol |
Solar
Variability |
QBO |
Enhanced Bry |
|
REF1 |
1980-2004 If
possible 1960 to 2004 |
OBS |
OBS used
for WMO/UNEP 2002 runs. |
OBS HadISST1
|
OBS Surface
Area Density data (SAD) |
OBS MAVER
data set, observed flux |
OBS or
internally generated |
- |
|
REF2 |
1980-2025 If
possible until 2050 |
OBS +
A1B(medium) |
OBS + Ab
scenario from WMO/UNEP 2002 |
Modeled SSTs |
Constant SADs |
Not included |
|
Only
internally generated |
- |
|
|
|
|
|
|
|
|
|
|
SCN1 |
1980-2004 |
OBS |
OBS used
for WMO/UNEP 2002 runs |
OBS |
OBS |
OBS |
OBS or
internally generated |
Included Based
on Salawitch et al. (2005) |
|
SCN2 |
1980-2025 |
OBS +
A1B(medium) |
OBS + Ab
scenario from WMO/UNEP 2002 |
Modeled SSTs |
Constant SADs |
OBS |
OBS
/ repeating in future or internally generated |
- |
(B) Reproducing the
past: Observed forcings for a transient model
simulation 1960 to present-day |
B1.
Greenhouse
Gases 1959 to present day (CO2, CH4,
N2O)
GHG used for WMO/UNEP 2002 runs and updated until 2004. The file gives surface volume mixing ratios of CH4 (ppbv), N2O (ppbv) and CO2 (ppmv)DOWNLOAD ---> Monthly mean data set 1959 to 2000 based on WMO (2003) and extended until 2004 (24 kB).
The
influence of the 11-year solar cycle on photolysis rates is
parameterized
according to the intensity of the 10.7 cm radiation of the sun (data
available
at: http://www.drao.nrc.ca/icarus/www/daily.html).
The
spectral distribution of changes in extra-terrestrial flux is based on
investigations presented by Lean et al. (1997).
Recommendation:
Use observed flux
(column 3 in maver_1951-2000.dat)
10,7 cm
solar flux from http://www.drao.nrc.ca/icarus/www/maver.txt
More explanation see http://www.drao.nrc.ca/icarus/www/sol_home.shtml
B5.
Assimilated
Quasi-Biennial
Oscillation (QBO)
The QBO has been assimilated in several studies
with the aim to
study QBO effects on the dynamics and/or chemistry. Often the
assimilation procedures assume a certain idealistic
meridional structure of the QBO jets and force the model to follow the
externally given vertical zonal wind structure within the QBO domain.
Even simple relaxation methods (see for example Giorgetta et al., 1999)
can provide fairly realistic QBO structures, and the GCM will generate
the secondary meridional circulation of the QBO and the related
temperature signal. This can provide a significant improvement for
certain experiments. The method implies nearly no costs compared to the
costs of the GCM integration.
The QBO is described by zonal wind profiles measured at the equator.
QBO
data sets provided by Marco Giorgetta (Contact for questions: Marco Giorgetta
)
Surface Area Density
data (SAD)
WMO2002 SAD dataset put together by
David Considine, LaRC. This data set is based on SAGE and SAM
data.
Monthly zonal mean surface area density climatology derived from
various satellite data.
DOWNLOAD ---> SAD
data set 1979 to 1999 (1.8 MB) provided by David Considine
(Contact for
questions: David Considine)
For the time period 1999 to 2004, please use 1999 values.
For the time period previous to 1979, please use 1979 values. For the
years 1963 to 1966 you might wish to add delta SADs for the eruption of
Agung that have been used in a transient simulation with E39/C (Dameris
et al., 2005). These data will be made available on request. Please
contact Martin Dameris.
B8.
Other
issues
Impact of new HCFCs (141B, 142B) (Contact for questions: Rolando Garcia and Doug Kinnison)
e.g.
instead of including HCFCs explicitly, we could instead use MCF,
HCFC22 and CH3Cl as "surrogates", as follows:
MCF --> MCF + 2/3 * HCFC141B
HCFC22 --> HCFC22 + 1.0 * HCFC142B
This approach was used in the WMO1998 2D model assessment. These
surrogates have similar tropospheric and stratospheric lifetimes as the
omitted HCFCs.
(C) Making
predictions: Forcings
for a transient model
simulation from present day to 2100 |
For REF2, SCN2:
UNEP/WMO Scientific
Assessment of Ozone Depletion: 2002
Chapter 1: Controlled substances and other trace gases
Scenarios from Archie McCulloch (Marbury Techn. Cons.), John Daniel
(NOAA/AL), Steve Montzka (NOAA/CMDL), and Guus Velders (RIVM/LLO),
September 21, 2001 (Version 3)
For the model
simulation, please use scenario
-> B2
a.
Fully coupled
atmosphere ocean CCMs with
the atmosphere extending to the middle
atmosphere, with coupled chemistry, use their internally calculated
SSTs
(probably beyond the possibilities for most groups).
b.
CCMs driven by SST
and sea ice of the underlying
IPCC coupled-ocean
model simulation could use
the model consistent SSTs. One constraint is to make the SST
data set consistent with the GHG scenario. However, if preferred, they
could
also decide to use the SSTs defined under (5c).
c.
All other CCM groups might
wish to run with
equal SSTs: We propose to
use the modeled SSTs from a Hadley Centre coupled
ocean-atmosphere model (HadGEM1) simulation
for the full time period
(1980 to 2025 or
longer) based
on the chosen GHG scenario.
SST and ice datesets
have been derived using output from UK Met Office HadGEM1
simulations using IPCC SRES scencario AIB performed for the IPCC fourth
assessment report. The
HadGEM1 simulations had historical anthropogenic forcing from
December 1970 to November 1999 (simulation started December 1859) , and
followed the SRES A1B scenario from December 1999 to December
2099. Volcanic stratospheric aerosols and solar irradiance were
constant. The data was
transformed from the HadGEM1 grid to the same 1x1 degree
grid used for the HadISST1 dataset. The fields are monthly means.
DOWNLOAD HadGEM data set--->
http://www.hadobs.org/. Under "Other Resources" click on "SST and sea-ice from HadGEM for 1970-2100".
(Contact
for
questions: Neal
Butchart)
QBO
data sets are provided by Marco Giorgetta (Contact for questions: Marco Giorgetta
)
(D) Model
Recommendations |
Rate Constants for Second-Order Reactions: JPL05 Table 1
Equilibrium Constants: JPL05
Table 3:
Heterogeneous chemistry: Use JPL 02 Section 5
These
fields will provide the data to test the chemistry schemes. The
instantaneous
(3D) output will be used to compare models with a standard
photochemical box
model and then with overall datasets from in-situ (e.g. ER-2) data.
These
fields will also be used to investigate the models’ treatments of polar
processing in the Arctic – hence the request for 1 common year (1999)
and your
model’s extreme Arctic years in the 1990-1999 period. The 2D fields
will be
used for a comparison with satellite climatologies and for an overview
comparison during the whole period (e.g. as aerosol levels change).
Certain
fields (e.g. PSC monthly surface area will also be an indication of
temperature
variability).
(E) Current Coupled
Chemistry-Climate Models |
Current
coupled chemistry-climate models
Table 2.
Model |
Horizontal
Resolution |
No.
Vertical Levels/ Upper Boundary |
Group and location |
Model Reference |
Contacts |
AMTRAC |
2 °x
2.5° |
48 / 0.0017
hPa |
|
Anderson et al. (2004); Austin (2002) |
J. Austin |
CCSR/
NIES |
T21 |
30 / 0.06 hPa |
NIES, |
Nagashima et al. (2002); Takigawa et al. (1999) |
H. Akiyoshi,
T. Nagashima, M. Takahashi |
CMAM |
T32 or T47 |
65 / 0.0006
hPa |
MSC, |
Beagley et al. (1997); de Grandpré et al.
(2000) |
T.G. Shepherd |
E39/C |
T30 |
39 / 10 hPa |
DLR |
Dameris et al. (2005) |
M. Dameris, V.
Eyring, V. Grewe, M. Ponater |
ECHAM5/ MESSy |
T42 |
90 / 0.01 hPa |
MPI |
Jöckel et al. (2004); Roeckner et al. (2003);
Sander et al. (2004) |
C. Brühl,
M. Giorgetta, P. Jöckel, E. Manzini, B. Steil |
FUB-CMAM-CHEM |
T21 |
34 / 0.0068
hPa |
FU Berlin,
MPI |
Langematz,
et al. (2005) |
U.
Langematz |
GCCM |
T42 |
18 / 2.5 hPa |
|
Wong et al. (2004) |
M. Gauss, |
GEOS CCM
|
2° x
2.5° |
55 / 80km |
NASA/GSFC, |
In preparation |
A. Douglass,
P.A. Newman, S. Pawson, R. Stolarski |
GISS |
4° x
5° |
23 / 0.002 hPa |
NASA GISS, |
Schmidt et al. (2005a) |
D. Rind, D.
Shindell |
HAMMONIA |
T31 |
67 / 2.10-7
hPa |
MPI |
Schmidt et al. (2005b) |
G. Brasseur, M.
Giorgetta, H. Schmidt |
LMDREPRO |
2.5° x
3.75° |
50 / 0.07 hPa |
IPSL, France |
In preparation |
S. Bekki, D.
Hauglustaine, L. Jourdain |
MAECHAM
/CHEM |
T30 |
39 / 0.01 hPa |
MPI |
Manzini et al. (2003); Steil et al. (2003) |
C. Brühl,
M. Giorgetta, E. Manzini, B. Steil |
MRI |
T42 |
68 / 0.01 hPa |
MRI, |
Shibata and Deushi
(2005); Shibata et al. (2005) |
K.
Shibata |
SOCOL |
T30 |
39 / 0.01 hPa |
PMOD/WRC and
ETHZ, |
Egorova et al. (2004) |
E.
Rozanov |
ULAQ |
10° x
20° |
26 / 0.04 hPa |
|
Pitari et al. (2002) |
E. Mancini, G.
Pitari |
UMETRAC |
2.5° x
3.75° |
64 / 0.01 hPa |
NIWA
Lauder (NZ) |
|
G.
Bodeker, N. Butchart, H. Struthers |
UM
SLIMCAT |
2.5° x
3.75° |
64 / 0.01 hPa |
|
Tian and
Chipperfield (2005) |
M.P. Chipperfield, W. Tian |
UMUCAM |
2.5° x
3.75° |
58 / 0.1 hPa |
|
Braesicke and
Pyle (2003 and 2004) |
P. Braesicke,
J.A. Pyle |
WACCM3 |
2° x
2.5° |
66 / 140 km |
|
Sassi et
al. (2005) |
B. Boville, R.
Garcia, A. Gettelman, D. Kinnison, D. Marsh |
(F) References |
Anderson,
J.L. et
al., 2004: The new GFDL global atmosphere and land model AM2/LM2:
Evaluation with prescribed SST simulations, J. Climate, in press.
Austin,
J., 2002:
A three-dimensional coupled
chemistry-climate model simulation of past stratospheric trends, J.
Atmos.
Sci., 59, 218-232.
Austin,
J. and N. Butchart, 2003: Coupled chemistry-climate model simulation
for the
period 1980 to 2020: ozone depletion and the start of ozone recovery,
Q. J. R.
Meteorol. Soc., 129, 3,225-3,249.
Beagley,
S.R. et
al., 1997: Radiative-dynamical climatology of the first-generation
Canadian
Middle Atmosphere Model, Atmos.-Ocean, 35, 293-331.
Braesicke,
P. and
J. A. Pyle, 2003: Changing ozone and
changing circulation: Possible feedbacks?, Geophys. Res. Lett., 30(2),
1059,
doi:10.1029/2002GL015973.
Braesicke,
P. and
J.A. Pyle, 2004: Sensitivity of
dynamics and ozone to different representations of SSTs in the Unified
Model,
Q. J. R. Meteorol. Soc., 130, 2,033-2,046.
Dameris, M. et al.,
2005: Long-term changes and
variability in a transient simulation with a chemistry-climate model
employing
realistic forcings, Atmos.
Chem.
Phys. Discuss., 5, 2297-2353.
de
Grandpré, J. et
al., 2000: Ozone climatology using interactive chemistry: Results
from the
Canadian Middle Atmosphere Model, J. Geophys. Res., 105, 26,475-26,491.
Egorova,
T. et al., 2005: Chemistry-climate model
SOCOL: a validation of the present-day climatology, Atmos. Chem. Phys.
Discuss., 5, 509-555.
Eyring V. et al.,
2004: Comprehensive
Summary on the Workshop on "Process-Oriented Validation of Coupled
Chemistry-Climate Models", SPARC Newsletter No. 23, p. 5-11,
http://www.atmosp.physics.utoronto.ca/SPARC/News23/23_Eyring.html.
Eyring,
V. et
al., 2005: A strategy for process-oriented validation of coupled
chemistry-climate models, Bull. Am. Meteorol. Soc., in press.
IPCC,
2000: Emission Scenarios. A Special Report of
IPCC Working Group III,
Jöckel,
P.
et al., 2005: Technical Note: The
Modular Earth Submodel System (MESSy) - a new approach towards Earth
System
Modeling, Atmos. Chem. Phys., 5, 433-444.
Labitzke,
K. et
al. 2002: The Berlin stratospheric
data series. Meteorological Institute, Free
Langematz,
U. et
al., 2005: Chemical effects in 11-year solar cycle simulations with
the
Freie Universitaet Berlin Climate Middle Atmosphere Model
(FUB-CMAM-CHEM),
Geophys. Res. Lett., in press.
Lean,
J. et al.,
1997: Detection and parameterization of variations in solar mid and
near
ultrviolet radiation (200 to 400 nm). J. Geophys. Res., 102,
29,939-29,956.
Manzini,
E. et
al., 2003: A new interactive chemistry climate model. 2:
Sensitivity of the
middle atmosphere to ozone depletion and increase in greenhouse gases:
implications for recent stratospheric cooling, J. Geophys. Res.,
108(D14),
4429, doi:10.1029/2002JD002977.
Nagashima,
T. et
al., 2002: Future development of the ozone layer calculated by a
general
circulation model with fully interactive chemistry, Geophys. Res.
Lett., 29
(8), 1162, doi: 10.1029/2001GL014026.
Naujokat, B.,
1986: An update of the observed quasi-biennial oscillation of the
stratospheric
winds over the tropics. J. Atmos. Sci., 43, 1873-1877.
Pawson,
S. et
al., 2000: The GCM-Reality Inter-comparison Project for SPARC:
Scientific
Issues and Initial Results, Bull. Am. Meteorol. Soc., 81, 781-796.
Pitari,
G. et al., 2002: Feedback of future
climate and sulfur emission changes an stratospheric aerosols and
ozone, J.
Atmos. Sci., 59(3), 414–440.
Rayner,
N.A. et al., 2003: Global analyses of
sea surface temperature, sea ice, and night marine air temperature
since the
late nineteenth century, J. Geophys. Res., 108, No. D14, 4407
10.1029/2002JD002670.
Roeckner
E. et
al., 2003: The atmospheric general circulation model ECHAM5, Part
1, MPI
Report, No. 349, ISSN 0937-1060.
Salawitch,
R.J. et
al., 2005: Sensitivity of Ozone to Bromine in the Lower
Stratosphere,
Geophys. Res. Lett., in press.
Sander,
R. et al., 2005: Technical Note: The new
comprehensive atmospheric chemistry module
Sassi,
F. et al., 2005: The effects of interactive
ozone chemistry on simulations of the middle atmosphere, Geophys. Res.
Lett.,
submitted.
Schmidt,
G.A. et al., 2005a: Present day atmospheric
simulations using GISS ModelE: Comparison to in-situ, satellite and
reanalysis
data, J. Climate, in press.
Schmidt,
H. et al., 2005b: The HAMMONIA Chemistry
Climate Model: Sensitivity of the Mesopause Region to the 11-year Solar
Cycle
and CO2 Doubling, J. Climate, submitted.
Shibata,
K and M.
Deushi, 2005: Partitioning between resolved wave forcing and unresolved
gravity
wave forcing to the quasi-biennial oscillation as revealed with a
coupled
chemistry-climate model, Geophys. Res.
Lett., in press.
Shibata,
K. et al., 2005: Development of an MRI
chemical transport model for the study of stratospheric chemistry, Papers in Geophysics and Meteorology,
55, 75-118, in press.
Steil,
B. et al., 2003: A new interactive
chemistry climate model. 1: Present day climatology and interannual
variability
of the middle atmosphere using the model and 9 years of HALOE/UARS
data, J.
Geophys. Res., 108(D9), 4290,doi:10.1029/2002JD002971.
Takigawa,
M. et al., 1999: Simulation of ozone
and other chemical species using a Center for Climate Systems
Research/National
Institute for Environmental Studies atmospheric GCM with coupled
stratospheric
chemistry, J. Geophys. Res., 104, 14,003-14,018.
Tian,
W. and M.P. Chipperfield, 2005: A New coupled chemistry-climate model
for the
stratosphere: The importance of coupling for future O3-climate
predictions,
Q.J. Roy. Met. Soc., 131, 281-303.
WMO,
2003: Scientific Assessment of Ozone Depletion: 2002, Global Ozone
Research and
Monitoring Project - Report No. 47, 498 pp,
Wong,
S. et al., 2004: A global
climate-chemistry model study of present-day tropospheric chemistry and
radiative forcing from changes in tropospheric O3 since the
preindustrial
period, J. Geophys. Res., 109, No. D11,doi:10.1029/2003JD003998.
Last modified: July 6, 2005 by Veronika Eyring |