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Climate Change Working
Group (CCWG)
July, 2004
Co-chairs: Gerald A. Meehl,
Ben Santer, and
Warren
Washington
Currently Active Global Coupled Climate Models
PCM
atmosphere: CCM3.2, T42, 18L
ocean: POP, 2/3 to 1/2 degree in eq. Tropics, 32L,
biharmonic diffusion, Pacanowski/Philander mixing
sea ice: dynamic (EVP), thermodynamic
land surface: LSM
CCSM2 atmosphere: CAM2, T42, 26L
ocean: POP, 1 to 1/2 degree in eq. Tropics, 40L, GM, KPP
sea ice: dynamic (EVP), thermodynamic
land: CLM
CCSM3 atmosphere: CAM3, T85, 26L
ocean: POP, 1 to 1/2 degree in eq. Tropics, 40L, GM, KPP
sea ice: dynamic (EVP), thermodynamic
land: CLM
(T42 class models run 8 years per day on IBM SP Power4; T85 is about a factor
of two slower)
CCSM3 is current active model for new climate change
experiments for the CCWG
CCSM2 used mainly for CMIP thermohaline
circulation sensitivity experiments
PCM being run only for limited experiments to
leverage information from the large archive of
completed 20th and 21st century climate simulations
PCM 20th, 21st and 22nd Century Simulations
•
Volcano-only, 1870-2000, 4 members
•
Ozone-only, 1870-2000, 4 members
•
GHG-only, 1870-2000, 4 members
•
Sulfate aerosol-only, 1870-2000, 4 members
•
GHG+ozone, 1870-2000, 4 members
•
Solar+ozone, 1870-2000, 4 members
•
Solar-only, 1870-2000, 4 members
•
GHG+sulfates+ozone, 1870-2000, 10 members
•
GHG+sulfates+ozone+solar, 1870-2000, 4 members
•
GHG+sulfates+ozone+solar+volcano, 1870-2000, 4 members
•
Solar+volcano, 1870-2000, 4 members
•
Solar+volcano+ozone, 1870-2000, 4 members
•
GHG+sulfates, 1870-2000, 4 members
•
control simulation (1500 years)
•
1% CO2 increase to doubling (5 members), and quadrupling (1 member); 150 years at
2XCO2, 150 years at 4XCO2; (CMIP)
•
ACACIA “Business as Usual”, 5 members, 2000-2100; 1 member to 2200
•
ACACIA “stabilization”, 5 members, 2000-2100, 1 member to 2200
•
SRES A2 ,B2, A1FI (single members), A1B and B1 (four members), 2000-2100
•
SRES A1B and B1 stabilized at 2100 values run to 2200 (four members), one each to 2300
•
20th century stabilization to 2100 (four members)
•
Land surface change experiments
The PCM set of simulations represents perhaps the
largest global coupled model dataset of multi-member
ensemble 20th and 21st century climate simulations,
performed with a single model, currently in existence
Over 190 simulations
Over 21,000 years of simulation
100 Tb
Another source for model output
• A large database of PCM and CCSM2 results have
been postprocessed and quality controlled for easy
distribution to the scientific community.
• Over 80 PCM runs
– Atmospheric monthly and daily data.
– Oceanic monthly data.
• CCSM2.0.1 control run (years 350-999)
• See http://www.nersc.gov/projects/gcm_data/ for
details or email [email protected]
List of runs for IPCC AR4:
1. 20th century simulation to year 2000, then fix all concentrations at year 2000
values and run to 2100 (CO2 ~ 360ppm)
2. 21st century simulation with SRES A1B to 2100, then fix all concentrations at
year 2100 values to 2200 (CO2 ~ 720ppm)
3. 21st century simulation with SRES B1 to 2100, then fix all concentrations at
year 2100 values to 2200 (CO2 ~ 550ppm)
4. 21st century simulation with SRES A2 to 2100
5. 1% CO2 run to year 80 where CO2 doubles at year 70 with corresponding
control run
6. 100 year (minimum) control run including same time period as in 1 above
7. 2XCO2 equilibrium with atmosphere-slab ocean
8. Extend one A1B and B1 simulation to 2300
9. 1% CO2 run to quadrupling with an additional 150 years with CO2 fixed at
4XCO2
10. 1% CO2 run to doubling with an additional 150 years with CO2 fixed at
2XCO2
CCSM3 T85 IPCC Simulations
2XCO2 = 2.1°C
TCR = 1.32 °C
CCSM3: 2XCO2 = 2.7 °C
TCR = 1.46 °C
PCM:
Earth Simulator CCSM3 Simulations
Global coupled climate model analyses for the IPCC AR4
Modeling groups around the world have agreed to perform an
unprecedented set of coordinated 20th and 21st Century climate
change experiments, in addition to commitment experiments
extending to the 22nd Century, for the IPCC Fourth Assessment
Report.
WGCM is coordinating an international effort to collect, archive
and analyze output from this multi-model dataset for direct input
to the IPCC AR4 in 2004-2005.
The WGCM Climate Simulation Panel has been set up to
oversee this effort [chair, Gerald Meehl (NCAR, USA), John
Mitchell (Hadley Centre, U.K.), Bryant McAvaney (BMRC,
Australia), Curt Covey (PCMDI, USA), Mojib Latif (MPI,
Germany), and Ron Stouffer (GFDL, USA)]. This panel is
coordinating the collection and archival of the multi-model
output at PCMDI. The initial deadline for submission of model
data is September 1, 2004.
Individuals and groups can sign up before September 1, 2004 to
analyze aspects of the simulations. An announcement has been
made inviting open participation (CLIVAR Exchanges, EOS,
BAMS, email). Contact [email protected] if you are
interested in participating.
Results will be presented at a Workshop on Analyses of
Climate Model Simulations for the IPCC AR4 March 1-4,
2005, convened by U.S. CLIVAR, and hosted by the
International Pacific Research Center, University of Hawaii.
Scientific papers describing the results presented at the
workshop must then be written by the respective investigators,
and submitted to peer-reviewed journals by the time of the
Second Lead Authors Meeting in May, 2005, in order to be fully
included and assessed in the AR4 as specified by the guidelines
of IPCC.
a.
Scientific objectives of the CCWG
Main theme: Quantifying uncertainty in climate change
projections
Requirements:
1. Improve regional climate simulation and extremes: higher
resolution atmospheric component, T85, T170 coupled
simulations; more outputs from model in time and space for
extremes analyses
2. Probabilistic projections of climate change: Ensemble
simulations with various forcings and scenarios
3. Understand model response to changes of forcing; climate
sensitivity a main issue
Planned CCSM3 simulations
T170 AMIP simulation
T170 CCSM3 coupled simulation, 1950 - 2050
T85 Historical simulation from 1870 to 2000 (GHGs + SA +SAI
+SV+ V + O) (130 years) with sulfate aerosols (direct and indirect
effect)
T85 Historical simulation from 1870 to 2000 (GHGs + SA +SV+
V+ O + CA) (130 years) with carbon aerosols varying in space
and time
T85 Historical simulation from 1870 to 2000 (GHGs + SA +SV+
V+ O + DA) (130 years) with dust aerosols
T85 Historical simulation 1870 to 2000 with sulfate indirect only
T85 Historical simulation 1870 to 2000 with dust aerosols only
T85 Historical simulation 1870 to 2000 with carbon aerosols only