# Presentation: 907678

## Status of The Community Climate System Model CCSM3

- Bill Collins
- _[http://www.cgd.ucar.edu/~wcollins](http://www.cgd.ucar.edu/~wcollins)_
*Chair, CCSM Scientific Steering Committee*
*National Center for Atmospheric Research*
*Boulder, Colorado*

## 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.

## 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/](http://www.ccsm.ucar.edu/models/ccsm3.0/)_
- Number of downloads to date: 170 _[(Counter)](http://www.cgd.ucar.edu/cseg/csm3.0/hitcount.html)_

## 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

## 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.

## 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/](https://www.earthsystemgrid.org/)_
- Future: Distribution of source code?

## The Experimental Configuration

- 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)

## Experimental Design

| Forcing | 20th Century | 21st-23rd Century |
| --- | --- | --- |
| Greenhouse Gases | Observed | SRES |
| Ozone | Trop: MOZART
Strat: Solomon | Trop: MOZART scaled by O3 TAR forcing 
Strat: Solomon |
| Sulfate Aerosols | SO2: Smith/Wigley | SO2: SRES |
| Carbon Aerosols | Population Scaling | SO2 Scaling |
| Sea-salt & Dust | Year 2000 values | Year 2000 values |
| Volcanic Aerosols | Ammann (2003) | Year 2000 values |
| Solar Variation | Lean (1995) | Year 2000 values |
| Indirect Effects | None | None |

## 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.

## 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.

## Comparison of CCSM3 and Global Surface Temperatures

- CCWG/Arblaster

**Notes:**
Please see the attached PowerPoint file containing plots of
globally averaged TS using the all-forcing runs of the CCSM3.
Only 4 of the b30.030 ensemble members were available when I made
these. I can update them with the 5th member and the ES members
if you would prefer. The shading shows the ensemble spread and
the solid lines the ensemble average. The black line is the
observations used in the IPCC TAR (Folland et al 2001).

Bias at end of run = ??

## Projections for the 21st Century

- 

## 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

## SST Biases in W. Coastal Regions

- 

**Notes:**
(SST_BIAS.gif) Warm SST bias of the western coasts of the
        continents, e.g.. South America, South Africa, and California.
        The figure shows the model SST and model-obs SST distributions.
        In some sensitivity experiments, we have shown that these
        are not just benign local responses, but they have remote
        effects particularly on the model's ITCZ. For example, eliminating
        the bias off the South African coast eliminates the double
        ITCZ structure in the Equatorial Atlantic.

## Semi-Annual SST Cycle

- Anomaly: Observations

- Anomaly: T851

**Notes:**
(SST_SEASONAL_CYCLE.gif) Tropical variability including
        the SST seasonal cycle and the ENSO frequency. The figure
        shows the SST seasonal cycle anomaly for b30.009 in comparison
        with the R&S data. The model has a strong semi-annual signal.
        PLEASE NOTE THAT WE NEED SERIOUS COMMITMENT FROM THE AMWG
        TO PURSUE THIS ISSUE FURTHER!!!!!

R&S = Reynolds and Smith

## Periodicity of ENSO

- NCEP Monthly Nino 3.4 =0.82 K

-  T851 Monthly Nino 3.4 =0.77 K

- 

## Double ITCZ Issue

## 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 for development of prototype:
- Target = 2005?
- All pieces exist & run in CCSM3 component models.

## Multi-Century Coupled Carbon/Climate Simulations 

**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**

**Surface Temp.**

- 13.6

- 14.1

**Net CO****2**** Flux (Pg C/yr)**

- -2.0

- +2.0

- Doney and Fung

**Notes:**
CSM 1.0 Coupled Carbon

## 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

## 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