Status of The Community Climate System Model CCSM3

1. Status of The Community Climate System Model CCSM3 Bill Collins http://www.cgd.ucar.edu/~wcollins Chair, CCSM Scientific Steering Committee National Center for Atmospheric Research Boulder, Colorado

2. NCAR Staff supported by SciDAC • Jean-Francois Lamarque (ACD): • Development of reactive chemistry for CCSM. • Simulations of radiatively active species. • Wei Yu (CGD): • Development of testing methodologies. • Infrastructure for portability. • Software engineer for biogeochemistry: • Hiring process has started.

3. Release of CCSM3 • Release Date: June 23, 2004 • Contents: • Code, input data, and scripts • Documentation • Simulations for present-day and pre-industrial conditions • URL:http://www.ccsm.ucar.edu/models/ccsm3.0/ • Number of downloads to date: 170(Counter)

4. Improvements in CCSM3 since CCSM2 • Atmosphere: • New cloud and ice-phase processes • Updated radiative treatment of H2O • New parameterizations of aerosol forcing • Dynamics suitable for chemistry • Land: • New methods for dynamic vegetation & C/N cycles • Changes to biogeophysics for biases • Ocean: • Improvements to ocean mixed layer • Solar heating by chlorophyll • Sea Ice: • Numerical improvements in ice advection • More accurate representation of surface stresses on ice • Inclusion of salt in ocean-ice mass exchanges

5. Portability of CCSM3 • Supported machines: 16 • Linux platforms with climate validation • CGD systems • Jazz at ANL • Lodestone at SIO • ORNL Cray X1 has just passed climate validation.

6. Distribution of CCSM3 Control Runs • Central site: Earth System Grid • DOE project to integrate major centersfor supercomputing and analysis • CCSM3 output available: • Current contents: 15 simulations (3 resolutions  5 types) • Averaged data sets: Open access • Data volume: 3850 years of integration • Access point: https://www.earthsystemgrid.org/ • Future: Distribution of source code?

7. Three phases: Pre-industrial (1870) 20th Century (1870-2000) Emissions Scenarios SRES Scenarios: Commitment (20th C. CO2) 2000-2100 (8 runs) 2100-2200 (2 runs) A1B and B1 Scenarios 2000-2100 (8 runs) 2100-2200 Const (8 runs) 2200-2300 Const (2 runs) A2 Scenario 2000-2100 (8 runs) The Experimental Configuration

8. Experimental Design

9. Summary of CCSM Runs for IPCC AR4 • Total simulation length: 10,800 years • Resolution: T85 (atm/land), 1o (ocn/ice) • Profile of CCSM in PCMDI archive: • > 40% of the total archive. • Largest ensemble in the archive.

10. CCSM Workshop on IPCC? • Target date: 2007? • After IPCC plenary & end of embargo • Information available from AR4: • Major uncertainties in forcing & response. • Emerging scientific priorities. • Goals of the workshop: • Experimental design for CCSM runs in AR5. • Requirements for CCSM4.0 (resolution/forcings). • Requirements for ensemble size. • Methods for interacting with WGs II and III.

11. Comparison of CCSM3 and Global Surface Temperatures CCWG/Arblaster

12. Projections for the 21st Century 

13. Near-term Goals of the CCSM Project • Program Plan for resource allocation: • Development of 1st generation coupled chemistry-climate model • Near-term development in component models • Steps toward single executable version of CCSM • Description of CCSM in literature: • Special issue of J. Climate • Int. J. High Performance Computing Applications • CCSM Workshop 2005: • Coupled Biases

14. SST Biases in W. Coastal Regions 

15. Semi-Annual SST Cycle Anomaly: Observations Anomaly: T851

16. Periodicity of ENSO T851 Monthly Nino 3.4 =0.77 K NCEP Monthly Nino 3.4 =0.82 K 

17. Double ITCZ Issue

18. 1st Generation Chemistry-Climate Model • Components: • Processes for stratosphere through thermosphere • Reactive chemistry in the troposphere • Oceanic and terrestrial biogeochemistry • Isotopes of H2O and CO2 • Prognostic natural and anthropogenic aerosols • Chemical transport modeling inside CCSM • Time line fordevelopment of prototype: • Target = 2005? • All pieces exist & run in CCSM3 component models.

19. Multi-Century Coupled Carbon/Climate Simulations +2.0 14.1 13.6 -2.0 Net CO2 Flux (Pg C/yr) Surface Temp. • Fully prognostic land/ocn BGC and carbon/radiation • Atm-Land: 70 PgC/yr ; Atm-Ocean: 90 PgC/yr  • Net Land+ocean: 01 PgC/yr • “Stable” carbon cycle and climate over 1000y • Projection of climate change on natural modes • Detection & attribution • Future climate projections/fossil fuel perturbations Doney and Fung

20. Recommendation for Near-Term Priorities High-resolution, process-oriented climate modeling • Goal: increase resolution & improve physics concurrently • Target resolutions: • Ocean and sea-ice: 0.1 degree • Atmosphere and land: T341 • Physics needed for target resolutions: • Improved closures in the ocean. • Improved treatments in the atmosphere of: • Convection • Clouds • Cloud water • The boundary layer

21. Conclusions • Recent Accomplishments • New Version (CCSM3) and its release • Code includes major scientific and software improvements • Large number of new runs (e.g., IPCC) • Growing community involvement • Analysis well underway • Interdisciplinary program to extend the model • Coupled Chemistry/Climate • Biogeochemistry • Land use • Near-term objectives: • Improve simulation of physical climate system • More hypothesis driven experiments