Transcript No Slide Title

The Community Climate System Model (CCSM):
An Overview
Jim Hurrell
Director
Climate and Global Dynamics Division
[email protected]
Climate and Ecosystem Community Planning Meeting
November 2-3, 2005
Boulder, CO
The Community Climate System Model
•
A comprehensive climate
model to study the Earth’s
Climate.
•
Widely used to investigate the
mechanisms of seasonal,
interannual and longer-term
variability.
•
Explore the history of Earth’s
climate.
•
Estimate the future of the
environment for policy
formulation.
http://www.ccsm.ucar.edu
Evolution of CCSM
J. Climate, 1998
(Boville and Gent, 1998)
CSM 1.0
June 1996
New ocean, land, sea-ice models
New physics in atmospheric model
Kiehl and Gent, 2004
CCSM 2.0
May 2002
New physics in all components
J. Climate, 2006
(Collins et al., 2006)
IJHPCA, 2005
CCSM 3.0
June 2004
Configuration of NCAR CCSM3
Atmosphere
(CAM 3.0)
T85 (1.4o)
Land
(CLM 3.0)
T85
(1.4o)
Coupler
(CPL 6)
Ocean
(POP 1.4.3)
(1o)
Sea Ice
(CSIM 4)
(1o)
Standard Configurations
T31 x 3
T85 x 1
T42 x 1
To facilitate its application,
CCSM has been ported to both
vector and scalar supercomputers
as well as Linux clusters
On an IBM SP4 system, the low,
intermediate and high resolution
configurations require 62, 292, and 1146
CPU hours to simulate one year
(Yeager et al. 2006)
Organization of the CCSM Project
CCSM SSC
Atmosphere
Model
Working Group
Paleoclimate
Working Group
Ocean Model
Working Group
CCSM
Advisory Board
Land Model
Polar Climate
Working Group Working Group
Climate Variability Biogeochemistry Climate Change
Working Group
Working Group Working Group
ChemistryClimate
Working
Group
Software
Engineering
Working Group
Contributions to IPCC Fourth Assessment
• Three phases:
– Pre-industrial (1870)
– 20th Century (1870-2000)
– Emissions Scenarios
• SRES Scenarios:
– Commitment (20th C. CO2)
• 2000-2100 (8 runs)
• 2100-2200 (4 runs)
– A1B and B1 Scenarios
• 2000-2100 (8 runs)
• 2100-2200 Const (5 runs)
• 2200-2300 Const (1 run)
– A2 Scenario
• 2000-2100 (8 runs)
A1B
B1
Commitment
Contributions to IPCC Fourth Assessment
• Output: 10 GB/simulated year
• Data volume for IPCC: ~100 TB
• Largest contribution of any model
• Eight ensemble members at T85
for each experiment
• Data available online:
• PCMDI (IPCC archive)
• ESG (Control)
• Original history tapes: SCD
• Diagnostics on line (web)
CCSM J. Climate Special Issue
(http://www.ccsm.ucar.edu/publications/jclim04)
• Objectives
 Describe CCSM3 to the climate community
 Document CCSM3 for IPCC FAR
• Topics
 Overview of CCSM3
 Description of climate state for each component model
 Responses (paleoclimate; pre-industrial; 20th & 21st Century)
 Major modes of coupled variability
 Climate sensitivity
Recent Science Highlights
CCSM J. Climate Special Issue
• 26 papers
 SSC (1)
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Atmosphere Model (6)
Ocean Model (4)
Land Model (2)
Climate Change (2)
Climate Variability (4)
Polar Climate(4)
Paleoclimate (3)
• 680 pages (estimated)
• Authorship
 51 NCAR (22 lead authors)
 48 External
CCSM Simulation Improvements
Improved SLP Teleconnections to ENSO
99% sig.
Recent Science Highlights
CCSM IJHPCA Special Issue
• Objectives
Describe SE for climate models
Document performance and portability
•14 papers submitted
• Authorship
 14 NCAR (3 lead authors)
 27 External