Overview of the New CCMVal Reference and Sensitivity Simulations

in Support of Upcoming Ozone and Climate Assessments

and the Planned SPARC CCMVal Report

On behalf of the Chemistry-Climate Model Validation Activity for SPARC (CCMVal)



General questions regarding the specifications of the simulations and external forcings can be directed to Veronika Eyring.
Please directly contact the appropriate scientists for questions regarding specific data sets (see below).

Before downloading forcing files from this website, please fill out a brief questionnaire for documentation purposes. Please electronically return this form to Veronika Eyring. You will receive the access data for downloads from this website per email.

(A) SPARC Newsletter Summary of the new CCMVal reference and sensitivity simulations
(B) CCMVal Reference Simulation REF-B1: Reproducing the past: Forcings for a transient model simulation 1960 to present day
Forcings for the Reference Simulation REF-B0 can be derived from REF-B1 forcings.
(C) CCMVal Reference Simulation REF-B2: Making predictions: Forcings for a transient model simulation from 1960 to 2100
(D) CCMVal Sensitivity Simulations (in support of Chapter 3 of the WMO 2010 Assessment, see data request here)

(A) Summary of CCMVal simulations in support of the SPARC CCMVal Report and WMO 2010

Eyring, V., M. P. Chipperfield, M. A. Giorgetta, D. E. Kinnison, E. Manzini, K. Matthes, P. A. Newman, S. Pawson, T. G. Shepherd, and D. W. Waugh (2008), Overview of the New CCMVal Reference and Sensitivity Simulations in Support of Upcoming Ozone and Climate Assessments and the Planned SPARC CCMVal, SPARC Newsletter No. 30, in press.

(B) Reproducing the past: Observed forcings for REF-B1 (Core time period 1960 to 2006)

B1. Greenhouse Gases (CO2, CH4, N2O) in REF-B1

Greenhouse Gases (N2O, CH4, and CO2) from 1950 and 2006. The file gives surface volume mixing ratios of CH4 (ppbv), N2O (ppbv) and CO2 (ppmv) from IPCC [2001]. CH4 has been altered starting on 2002.49 using data from the NOAA Cooperative Global Air Samling Netwook to account for the observed lower growth rates of CH4 in recent years.

DOWNLOAD --->    Monthly mean data set (1850 - 2006)

    (Contact for questions: Doug Kinnison)

B2.   Halogens in REF-B1

Surface mixing ratios of Ozone Depleting Substances
(CFC-11, CFC-12, CFC-113, CFC-114, CFC-115, CCl4, CH3CCl3, HCFC-22, HCFC-141b, HCFC-142b, Halon1211, Halon1202, Halon1301, and Halon2402) in REF-B1 are taken from Table 8-5 of WMO [2007]. The mixing ratios are calculated by a box model using yearly emissions and are given for the middle of the month. The time series does not contain a yearly variation in mixing ratios. Through 2004 the values are as much as possible forced to equal global estimates calculated from observations (for details see Chapter 8 of WMO [2007]). For models that do not wish to represent all the brominated and chlorinated species in Table 8-5 of WMO [2007], the halogen content of species that are considered should be adjusted such that model inputs for total chlorine and total bromine match the time series of total chlorine and bromine given in this table.

    DOWNLOAD ---> Monthly mean data set (1951 to 2100) based on WMO (2007), Table 8-5

    (Contact for questions: Guus J. M. Velders)

B3.   Sea Surface Temperatures and Sea Ice Concentrations in REF-B1

Sea surface temperatures and sea ice concentrations in REF-B1 are prescribed as monthly mean
boundary conditions
following the global sea ice concentration 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. To prepare the data for use in forcing a model, and in particular to correct for the loss of variance due to time-interpolation of monthly mean data, it is recommended that each group follows the procedures described on the C20C project web (see This describes how to apply the AMIP II variance correction method (see for details) to the HadISST1 data.

    DOWNLOAD Hadley Centre Sea Ice and SST data set (HadISST) ---> Follow the link "Marine Data" and "HadISST -     Globally complete sea-ice and sea-surface temperature".

B4.   Solar Cycle in REF-B1

Solar Irradiance Data
for the REF-B1 simulations are specified at the SOLARIS website:
To account for the highly variable and wavelength-dependent changes in solar irradiance, daily spectrally resolved solar irradiance data from 1 Jan 1950 to 31 Dec 2006 (in W/m2/nm) are provided. The data are derived with the method described in Lean et al. [2005] and are available with the following spectral resolution: 1 nm bins from 0 to 750 nm; 5 nm bins from 750 to 5000 nm; 10 nm bins from 5000 to 10000 nm; 50 nm bins from 10000 to 100000 nm. Each modeling group is required to integrate these data over the individual wavelength intervals (a) in their radiation scheme (to adjust the shortwave heating rates) and (b) in their chemistry scheme (to adjust the photolysis rates). It is recommended to use the provided solar flux data directly (integrated over the respective intervals in the radiation and chemistry schemes), rather than a parameterization with the F10.7 cm radio flux previously used. Additional information as well as the data can be found on the SOLARIS website.

    GO TO ---> 
SOLARIS website to download the data
    (Contact for questions: Katja Matthes)

B5.   Assimilated Quasi-Biennial Oscillation (QBO)  in REF-B1

The QBO is generally described by zonal wind profiles measured at the equator. The QBO is an internal mode of variability of the atmosphere that dominates the interannual variability in wind in the tropical stratosphere and contributes to the variability in the extratropical dynamics. It is recognized that the QBO is important for understanding interannual variability in ozone and other constituents of the middle atmosphere, in the tropics and extratropics. Currently only a few atmospheric GCMs or CCMs simulate a realistic QBO and hence QBO related influences. Simulated QBOs are generally independent of observed time series because their phase evolutions are not bound by external boundary conditions. Realistic simulated QBOs, however, have similar periods, amplitudes and composite structures in observations. The assimilation of the QBO, for example by a relaxation of zonal winds in the QBO domain ("nudging"), hence may be useful for two reasons: First to obtain a QBO in GCMs that do not simulate the QBO internally, so that for example QBO effects on the general circulation are present; and second to synchronize the QBO simulated in a GCM with a given QBO time series, so that simulated QBO effects, for example on ozone, can be compared to observed signals.

GO TO --->  QBO website to download the data

(Contact for questions:
Marco Giorgetta

B6.   Surface Sulphate Area Densities (SADs) in REF-B1

Surface Sulphate Area Densitites (SADs)
from observations are considered in REF-B1. A monthly zonal mean time series for SADs from 1979 to 2004 was created using data from the SAGE I, SAGE II, SAM II, and SME instruments (units square microns per cubic centimeter). This time series was published in SPARC [2006]. In addition, uncertainties of the SAGE II data set are described in detail in Thomason et al. [2007]. The altitude and latitude range of this data set is 12 - 40 km and 80°S – 80°N respectively. The SPARC SAD data set does have data gaps, which occur mainly in lower tropical altitudes (below 16 km) and during the El Chichón period. Above 26 km there are large data gaps in the mid-to-high latitude region. There are also missing data at all altitudes in the high latitude polar regions. The NCAR group modified this new SPARC SAD data set for CCM applications by filling the missing data using a linear interpolation approach in altitude and latitude. Large gaps of data above 26 km were filled with background values of 0.01 square microns per cubic centimeter. The gaps in the upper troposphere, tropical latitudes, between 1982 and 1984 were not filled. Missing values are indicated with values lower and equal 0.

For the period between 1950-1962, 1968-1979, and 2005-2100, monthly means of a five-year period 1998 to 2002 with background aerosols were adopted. Further, the Agung eruption in 1963 was implemented (by Andrea Stenke). As a remedy we follow the method described in Dameris et al. [2005]. The well documented years following the eruption of Mt. Pinatubo (1991–1994) have been adopted and associated with the period 1963–1966 with modifications based on published results to account for differences in total mass of sulfate aerosols in the stratosphere, in maximum height of the eruption plumes, and in the volcanoes’ geographical location. Above the maximum vertical extent of Agung’s eruption plume the annual mean of 1979 has been incorporated. For the new CCMVal simulations, we recommend using the new modified SPARC SAD time series described above, in particular for those models that have a heterogeneous chemistry halogen activation approach based solely on the occurrence of super cooled ternary (STS) PSCs.

SAD data set 1950 to 2100 (14.6 MB)
(Contact for questions:
Simone Tilmes and Doug Kinnison)

B7.   Heating rates from volcanic aerosol in REF-B1


Stratospheric warming and tropospheric-surface cooling due to volcanic eruptions are either calculated on line by using aerosol data or by prescribing heating rates and surface forcing. For those models that don’t calculate this effect online, pre-calculated zonal mean aerosol heating rates (K/day) and net surface radiative forcing (W/m2) monthly means from January 1950 to December 1999 for all-sky condition are available on the CCMVal website. They were calculated using volcanic aerosol parameters from Sato et al. [1993], Hansen et al. [2002] and GISS ModelE radiative routines and climatology [Schmidt et al., 2006; G. Stenchikov and L. Oman, pers. communication, 2007]. In addition to the larger eruption (Agung, 1963; El Chichón, 1982; Pinatubo, 1991) smaller ones like Fernandina (1968 in Galapagos) and Fuego (1974 in Guatemala) are included. Surface radiative forcing is negative corresponding to cooling caused by volcanic aerosols. The right way to use these data sets to mimic effect of volcanic eruptions would be to apply heating rates to the atmosphere and cooling flux to the surface. Heating rates and surface forcing would characterize the entire volcanic effect that is: stratospheric warming and tropospheric-surface cooling. If the focus is on stratospheric processes only aerosol heating rates could be used without causing any problem.

DOWNLOAD --->    hrates_readascii.f, hrates.ascii, sfc_forcing.ascii
(Contact for questions: Gera Stenchikov)

B8.   Ozone and Aerosol Precursors in REF-B1

Emissions of ozone and aerosol precursors (CO, NMVOC, NOx and SO2) are averaged over the years 1998 to 2000 and are taken from an extended data set of the REanalysis of the TROpospheric chemical composition (RETRO) project [Schultz et al., 2007, see]. The RETRO emissions inventory is a comprehensive global gridded data set for anthropogenic and wildfire emissions over the past 40 years. The data set comprises a high level of detail in the speciation of NMVOC compounds. The data originates from a large variety of sources, including the TNO TEAM inventory, information on burnt area statistics, the regional fire model Reg-FIRM, and satellite data. In case of SO2, RETRO only provides biomass burning related emissions. Therefore, this data is combined with an interpolated version of EDGAR-HYDE 1.3 [Van Aardenne et al., 2001] and EDGAR 32FT2000 [Olivier et al., 2005; Van Aardenne et al., 2005]. For the spin-up period from 1950 to 1959 we recommend using the 1960 values from this data set. The data set will be extended through 2006 by using trend estimates and will be harmonized so that regional totals are the same as in RETRO for the year 2000.

    GO TO --->  Ozone and aerosol precursor website to download the data
(Contact for questions: Andreas Baumgärnter)

B9.   Other issues

Impact of new HCFCs (141B, 142B) 

e.g. instead of including HCFCs explicitly, we could 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.
(Contact for questions: Rolando Garcia and Doug Kinnison)

(C) Making predictions: Forcings for REF-B2 (Core time period 1960 to 2100)


C1. Greenhouse Gases (CO2, CH4, N2O) in REF-B2

Greenhouse Gas concentrations (N2O, CH4, and CO2) are taken from the IPCC [2000] ‘A1B’ scenario, to provide continuity with Eyring et al. [2007].

    DOWNLOAD --->    Monthly mean data set (1850 to 2100)

    Contact for questions: Doug Kinnison)

C2.   Halogens in REF-B2

Surface mixing ratios of Ozone Depleting Substances are based on the halogen scenario A1 from
WMO [2007]. However, at the 2007 Meeting of the Parties to the Montreal Protocol, the Parties agreed to an earlier phase out of HCFCs, with nearly a full phase out by Article 5 countries in 2030 ( The current scenario A1 does not include this phase out. Hence, a new scenario has been developed that includes this phase out (hereafter referred to as adjusted scenario A1). The adjusted scenario A1 will only have HCFCs adjusted; distributions of CFCs, Halons, and other non-HCFC species remain identical to the original scenario A1. The adjusted scenario A1 can be downloaded from the CCMVal website.

    DOWNLOAD --->
Monthly mean data set (1951 to 2100)

    (Contact for questions: Guus J. M. Velders)

C3.   Sea Surface Temperatures and Sea Ice Concentrations in REF-B2

Sea surface temperatures and sea ice concentrations in REF-B2.
One of the most critical issues is the design of the future simulation REF-B2. Discrepancies between observed and simulated SST and SICs complicate the selection of these fields for runs that span the past and the future. Because of potential discontinuities between the observed and modeled data record, the REF-B2 runs use simulated SSTs and SICs for the entire period. There are three alternate approaches, depending on the resources of each modeling group. First, groups that have fully coupled atmosphere-ocean models with coupled chemistry and a middle atmosphere should perform a fully coupled run that calculates the SSTs/SICs internally. Due to the inertia of the coupled atmosphere ocean system, such integrations should be started from equilibrated control simulations for preindustrial conditions, as it is standard for the 20th century integrations for IPCC. Second, groups that have a coupled atmosphere-ocean model that does not include chemistry should use their own modeled SSTs/SICs for 1960-2100 in their CCM run. Third, groups that do not have their own coupled ocean-atmosphere model should use SSTs/SICs from an A1B-scenario IPCC AR-4 simulation, for example from CCSM3 [Collins et al., 2007]. The SSTs from HADGEM1 used in the first CCMVal REF-B2 simulation have a cold bias with respect to observations [see Figure 3 of Johns et al., 2006], whereas the tropical SSTs from the CCSM3 are in better agreement with observations [Large and Danabasoglu, 2006]. Oldenborgh et al. [2005] present a multi-model study of the representation of El Nino in IPCC AR4 models.

DOWNLOAD --->    SSTs and SICs from an A1B scenario WCRP CMIP3 simulation, see data portal for multi-model output at PCMDI.


C4.   Solar Cycle in REF-B2 and SCN-B2d

For REF-B2:

Solar variability is not included in the reference simulation REF 2. We recommend to use average solar flux for the entire REF-B2 period.

For SCN-B2d:
Solar variability is included in SCN-B2d.
Solar Irradiance Data for SCN-B2d are specified at the SOLARIS website:

SCN-B2d is defined similar to REF-B1, with the inclusion of solar variability, volcanic activity, and the QBO in the past. Future forcings include a repeating solar cycle and QBO, under volcanically clean aerosol conditions. SSTs/SICs are simulated or prescribed as in REF-B2. GHGs and halogens will be the same as in REF-B2. We recommend using a repeating solar cycle based on the observed daily spectra described in Lean et al. [2005]. It is proposed to repeat the solar cycles 20 to 23 (1962-2004) and therefore neglect the extreme solar cycle 19 (peaking in 1957/58).

    GO TO ---> 
SOLARIS website to download the data
    (Contact for questions: Katja Matthes)

C5.   Assimilated Quasi-Biennial Oscillation (QBO) in REF-B2 and SCN-B2d

For REF-B2:
The QBO is not included in reference simulation REF 2 (neither in the past, nor in the future).

For SCN-B2d:
QBO is included in SCN-B2d.

C6 and C7.   Volcanic Eruptions and aerosol loading in REF-B2 and SCN-B2d


For REF-B2:
Volcanic eruptions are not included in the reference simulation REF 2.
For aerosol loading, please use 2000 values from the SPARC SAD datase, specified under B6.

For SCN-B2d:
Heating rates and SADs same as in REF-B1 until 2000, use background aerosol (year 2000) from the SPARC SAD dataset in the future, see B6.

C8.   Ozone and Aerosol Precursors in REF-B2 and SCN-B2d

Ozone and aerosol precursors in REF-B2 should be similar to REF-B1 until 2000 (extended RETRO data set, see B8.   Ozone and Aerosol Precursors in REF-B1), and use the adjusted B2 baseline IIASA scenario through 2100 [M. Amann and P. Rafai, pers. communication, 2007]. This data set is available from the IIASA website at Please note that the adjusted B2 IIASA scenario needs to be harmonized with the extended RETRO data set in 2000 in order to allow a smooth transition from past to future. For surface emissions of NOx, CO and HCHO and for aircraft emissions of NOx this has been done by Olaf Morgenstern.

    GO TO --->  Surface and aircraft emission files website to download the data
    (Contact for questions:
Olaf Morgenstern

Ozone and aerosol precursors in SCN-B2a: SCN-B2a is designed to be consistent with one of the new coordinated Climate Change Stabilization Experiments proposed for AOGCMs and ESMs [Meehl et al., 2007]. Emissions of all necessary chemical compounds will be provided, including ozone and aerosol precursors as well as primary aerosols and ozone-depleting substances. An international effort is currently in progress to complete this task. In particular, future emissions (2010-2300) will be generated by the Integrated Assessment Models (IAMs) responsible for the “representative concentration pathways” RCPs. In order to ensure continuity of emissions across 2000, the 2000 emissions are being used to harmonize emissions into the future and from the historical perspective as well.  Emissions (at 0.5 degrees, available every 10 years over 1850-2300) are expected to be available in the latter part of 2008.

(D) Sensistivity runs in support of Chapter 3 of WMO 2010, see data request here

This data request is for files that are needed from the CCMVal-2 sensitivity simulations that are proposed in addition to the CCMVal-2 reference simulations (REF-B1 and REF-B2) to support the upcoming 2010 WMO/UNEP Ozone Assessment, in particular Chapter 3. Future Ozone and its Impact on Surface UV. These sensitivity simulations will be analyzed in Chapter 3 in addition to the REF-B2 simulations. They are in order of importance for Chapter 3:

D1. Greenhouse Gases (CO2, CH4, N2O) in the  sensitivity simulations

Greenhouse Gas concentrations (N2O, CH4, and CO2) are taken from the IPCC [2000] SRES scenarios.

    DOWNLOAD --->    Monthly mean data set (1850 to 2100) for SRES B1
    DOWNLOAD --->    Monthly mean data set (1850 to 2100) for SRES B2
    DOWNLOAD --->    Monthly mean data set (1850 to 2100) for SRES A2
Contact for questions:
Doug Kinnison)

Alternatively, the new IPCC Representative Concentration Pathways (RCPs) are used in the sensitivity simulations (see CMIP5 website here). They require a change to a fully new set of emissions and thus mean more work. In addition consistent SSTs and SICs for the RCP simulation are not yet available, which means a delay in the start of the run. For all SRES scenarios, GHG scenario consistent SSTs and SICs can be taken from the WCRP CMIP3 archive from the same AOGCM (see data portal for multi-model output at PCMDI at The SCN-B2-RCP2.6(8.5) simulations have the advantage that they are consistent with the new IPCC RCPs, whereas the SRES based SCN-B2a runs are easier to implement and can be started right now since SSTs/SICs are available. It will depend on the priority of the group whether they run an SRES or RCP based GHG sensitivity simulation. SRES and RCP simulations are equally valuable to assess the sensitivity of ozone recovery to GHGs.

D2.   Halogens in the 'World Avoided' simulations (SCN-B2f)

    DOWNLOAD --->
Monthly mean data set (1951 to 2100)

    (Contact for questions: Paul Newman and Guus J. M. Velders)

Last modified:  August 17, 2009
by Veronika Eyring