CCMVal

GHG scenarios for WMO/UNEP 2002 runs. The file gives surface volume mixing ratios of CH4 (ppbv), N2O (ppbv) and CO2 (ppmv)

Data set 1959 to 2000 based on WMO (2003).

Surely it would be better to use observations up to present day.
But then, the future scenarios would need to be continuous from present-day.
Also, it would be desirbale to use the same GHGs than those used for the current IPCC runs for the AR4.

A2. Halogens (1950 to 2000)

A3. Sea Surface Temperatures 1950-2000

AGREEMENT ON OBSERVED SSTs needed. So far two data sets proposed (HadISST1 and AMIP)

Sea Surface Temperature prescribed as monthly means following the global sea ice and sea surface temperature (HadISST1) data set provided by UK Met Office Hadley Center (Rayner et al., 2003).
The data is available without charge, but please read the terms and conditions before using it. The UK Met Office Hadley Center also asks you to register before downloading the data.
Web site to download Sea Hadley Centre Sea Ice and SST data set (HadISST): follow the link Marine Data HadISST - Globally complete sea-ice and sea-surface temperatur

OR

AMIP dataset for SSTs (see http://www.ccsm.ucar.edu/models/atm-cam/sims/cam3.0/ and follow the appropriate links).

A4. Solar Cycle 1951-2000

The influence of the 11-year solar cycle on photolysis rates is parameterised 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).

Data Set for transient model simulations (maver_1951-2000.dat) (Contact for questions: Christoph Brühl)
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

A5. 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.

Care must be taken with regard to the effect of the QBO on vertical momentum fluxes, as provided by resolved vertically propagating waves or parameterized gravity waves, and the resulting vertical dynamical coupling between the QBO and thesemiannual oscillation ( SAO). If the QBO is assimilated, then its shear layers will act immediately as a filter on vertically propagating waves, resolved or parameterized. Hence wave mean-flow interacton will be intensified in the QBO domain and reduced at higher levels. This may lead to a substantial reduction of the zonal momentum fluxes passing the stratopause towards the mesosphere, with consequences for instance for the circulation above the QBO domain. This may cause changes for example in the SAO compared to the SAO in a simulation without QBO assimilation.

The QBO is described by zonal wind profiles measured at the equator.

QBO data sets provided by Marco Giorgetta (Contact for questions: Marco Giorgetta )

A6. Other issues

(a) Volcanic eruptions (Contact for questions: Rolando Garcia and Doug Kinnison)

Stratospheric aerosols. Some groups will include the impact of volcanic eruptions on the aerosol distribution, both in the chemistry and radiative packages.
* e.g. surface area density data set supplied to us by Susan Solomon. This data set is based on SAGEI, SAGE II, and SAM data (Thomason, et al). We are also examining the WMO2002 SAD dataset put together by David Considine, LaRC. This data set is also based on SAGE and SAM data.
* e.g. Heating from volcanic aerosols from the CAM approach by Bill Collins

(b) Impact of new HCFCs (141B, 142B, 123) (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
    CH3Cl --> CH3CL + 2.0 * HCFC123
This approach was used in the WMO1998 2D model assessment. These surrogates have similar tropospheric and stratospheric lifetimes as the omitted HCFCs.

A7. References

Rayner, N. A.; Parker, D. E.; Horton, E. B.; Folland, C. K.; Alexander, L. V.; Rowell, D. P.; Kent, E. C.; Kaplan, A. Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century J. Geophys. Res.Vol. 108, No. D14, 4407 10.1029/2002JD002670.

WMO, 2003: Scientific Assessment of Ozone Depletion: 2002. Global Ozone Research and Monitoring Project, Report No. 47, 498 pp, Geneva.

(B) Making predictions: Forcings for a transient model simulation 1990 to 2050 (or to 2100)

B1. Greenhouse Gases 2001-2100 (CO₂, CH₄, N₂O)

AGREEMENT ON SCENARIO needed. Scenarios proposed so far: IPCC scenario A1b (medium) or B2 for CH4, N2O, and CO2
COMMENT: The chapter of the next IPCC assessment (AR4) that includes the greenhouse gases will use the scenarios B1 (low case), A1b (medium), and A2 (high)

Since the IPCC AR4 results will be aligned with these selected scenarios, we suggest to use the medium A1b scenario.
For the model simulation, please use scenario A1b (medium).

GHG scenarios for WMO/UNEP 2003 runs. The file gives surface volume mixing ratios of CH4 (ppbv), N2O (ppbv) and CO2 (ppmv).
Download data:
IPCC B2 scenario, dataset 2001 to 2050 based on WMO (2003).
IPCC A1b scenario, dataset 2001 to 2050 based on WMO (2003).

B2. Halogens 2001-2100

AGREEMENT ON SCENARIO needed. So far proposed: Scenario Ab (best guess scenario), Scenario B2 (Table 4B-2 of WMO2003, page 4.90)

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 -> ?

Download data:
Data set (2001 to 2099) adopted from Table 1-16 WMO (2003), Scenario Ab (best guess scenario), year by year variations

Data set (2001 to 2100), Table 1-16 WMO (2003), Scenario Ab (best guess scenario)

Data set (1950 to 2050) based on WMO (2003), Table 4B-2. Halocarbon scenario used in the 2-D model calculations. This scenario is essentially the same
(except for a few small deviations) as the baseline scenario Ab described in Tables 1-13 and 1-16 of Chapter 1 of the WMO 2003 report.

B3. Sea Surface Temperatures 2001-2100

AGREEMENT ON FUTURE SSTs needed or a decision has to be made that each group runs with model compliant SSTs

Do we use a common SST dataset or does each group use the SSTs from the coupled ocean-atmosphere version of their own model?
Separate prediction runs would use SSTs from a coupled ocean-atmosphere model. The runs could start at a past date. Parts of the run could be validated against some past behaviour but not that associated with SST variability (e.g. ENSO events).
Some people argue for a common dataset, but if yes, which one?
E.g. we could agree that at least a subset of models uses the Hadley scenario for SST based on is92a.
It depends on to what extent we want to discuss the same climate or consider that this is one of the unknown variables.

B4. Solar Cycle 2001-2085

Data Set for transient model simulations (maver_2001-2085.dat) (Contact for questions: Christoph Brühl )

Recommendation: Use observed flux (column 3 in maver_2001-2080.dat), which is a continuation of observed 11-year cycle.

B5. Assimilated Quasi-Biennial Oscillation (QBO)

Soon on this web site

The QBO is described by zonal wind profiles measured at the equator.

QBO data sets for the future are provided by Marco Giorgetta (Contact for questions: Marco Giorgetta )

B6. Other issues

B7. References