CCSM3’s IPCC Simulations and Lessons Learned Bill Collins http://www.cgd.ucar.edu/~wcollins National Center for Atmospheric Research Boulder, Colorado IPCC Production and Data Transfer Scientific results from IPCC Simulations Lessons Learned

Contributions from CCSM to IPCC IPCC Emissions Scenarios CCSM3 Simulations IPCC 4th Assessment This slide shows three examples of how CCSM will contribute to IPCC, and so I can point out that new understanding from MMAP could pontentially have an impact on our contributions to international assessments and policy formation that would be far-reaching. Results: 10,000 simulated years Largest submission to IPCC 100 TB of model output

The Experimental Configuration (from IPCC TAR) A1B B1

Production Schedule of IPCC Runs

IPCC Ensembles on US Machines http://www.cgd.ucar.edu/ccr/ipcc_status/

US Simulations for IPCC FAR Phase Run Ensemble Members Base Extensions Total Years 1 1870 440 Coverage of 1870-2300 870 2 20th C. 5 130 650 3 Constant 2000-2100 500 A1B 2000-2200 2300 (1 ) 1100 A2 B1 Controls 1990 1%CO2 450 5670

Computational Resources for Simulations Execution speed: 3.5 years/day on 192 IBM Power-4 CPUs Time required to simulate 5370 years: 5670 / 3.5 = 1620 wall-clock days CPU time for 1 simulated year: 1146 CPU hours Equivalent number of CPU hours for IPCC runs: 5670  1146= 6.5  106 CPU hours

IPCC Ensembles on the Earth Simulator http://www.cgd.ucar.edu/oce/weese/status/ccsm_data.html All data has been transferred to NCAR mass store.

Statistics of the IPCC Ensembles Ensemble size: 20th Century: 8 A1B Scenario: 8 B1 Scenario: 8 Commitment: 8 A2 Scenario: 5 Total integration: 10,800 years Data volume: ~110 TB

Resolutions for all Modeling Groups Karl Taylor, PCMDI

Model Simulations by all Groups Karl Taylor, PCMDI

Transfer of the Data to PCMDI First 1-TB disk transferred to PCMDI in October. Three Disks are now in use. CCSM IPCC data is now on the PCMDI IPCC website: http://www-pcmdi.llnl.gov/ Estimated scheduling of data transfers: Details: http://swiki.ucar.edu/cgd-ccr/48 Sequence: 20thC: CAM monthly CAM daily/6hr CLM monthly Controls: Scenarios POP and CSIM monthly to follow.

Papers on CCSM IPCC Scenario Runs Meehl et al, 2005: How much more global warming and sea level rise? In press, Science Meehl et al, 2005: Climate change in the 20th and 21st centuries and climate change commitment in the CCSM3 Submitted to J. Climate Bryan et al, 2005: Response of the North Atlantic Thermohaline Circulation and Ventilation to Increasing Carbon Dioxide in CCSM3 Submitted to J. Climate Kyosei Consortium, 2005: Analysis of CO2 overshoot experiments

Global Temperature and Sea Level

Ocean Temperature and Overturning

Increases in Surface Temperature

Increases in Precipitation

Arctic Sea Ice Concentrations

Changes in Sea Ice Coverage

Lesson #1: Experimental Design Plan Contents & goals of the experiments Description of all forcing agents vs. time Description of pre-industrial spin-up Pre-industrial configuration tuned for energy balance? Simulation for year 2000 integrated backwards to 19th C.? Experimental basis for pre-industrial spin-up Description and plan for CCSM resource requirements CCSM software engineering support Development efforts by working groups and WG liaisons Plan and timeline for dissemination of experiments Distribution within the CCSM community Distribution to wider climate community

Lesson #2: Development of Forcings 20th Century 21st-23rd Century Greenhouse Gases Observed SRES Ozone Trop: MOZART Strat: Solomon Trop:MOZART scaled by O3 TAR forcing Sulfate Aerosols SO2: Smith/Wigley SO2: SRES Carbon Aerosols Population Scaling SO2 Scaling Sea-salt & Dust Year 2000 values Volcanic Aerosols Ammann (2003) Solar Variation Lean (1995) Indirect Effects None

Aerosol Optical Depths during 20th C. Sulfates Black & Organic Carbon Strat. Volcanics

Present-day Aerosol Optical Depths

Comparison of CCSM3 and Global Surface Temperatures 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 = ?? Eight-member ensemble: T85 atmosphere & land 1-degree ocean & sea-ice Meehl et al, 2004

Recommendations on Forcings Coordination with other groups: For example, Boucher’s shared SO4 data set Efforts for AR4 to develop common forcings Develop components of state-of-art forcings: Emissions as functions of space and time Chemical transport framework to simulate agents Parameterization development for indirect effects Exploration of indirect forcings, for example Effects of irrigation Effects of land-use change

Lesson #3: Design of Model Spin-up

Effects of Energy Balance on Ocean Temperature in 1870 Control Trend = 0.17 K/Century

Lesson #4: (Ideally) Start Early Sequential, not concurrent, mile-stones: Release of CCSM3 to the community Peer-reviewed documentation of CCSM3 Execution of IPCC experiments We did all of these in 2004!

Lesson #5: Check Throughput of Data Transfer

Lesson #6: Plan for all End Users Issue: CCSM output = 100 TB This is orders of magnitude more data than our colleagues in IPCC WG2 and WG3 are used to analyzing. How do we make the data accessible & usable? Recommendations for steps forward: NCAR’s GIS tool for model output?