Observed and Simulated Climate Change

1. Observed and Simulated Climate Change • Note deviation from Natural forcing (Green) that occurs in the 1960’s • Note strong synchronization produced by volcanic eruptions and subsequent cooling, eg. Agung(1963), El Chichon(1982),Pinatubo(1991) • Shaded regions show range of ensemble and inherent climate variability

2. Simulation of Future Climates • Simulated historical and future change in temperature from average assuming a Business-As-Usual scenario of increasing CO2 (1% per year) • Warming in the high latitudes is predicted along with changes in ocean circulation and precipitation patterns • Improved regional detail requires high-end computational facilities

3. Simulation of Global DMS Flux from the Ocean(David Erickson(ORNL), Jose Hernandez(JICS), Matt Maltrud(LANL), Shaoping Chu(LANL))  A key climate interaction of an active biochemical ocean and atmosphere is through the sulfur cycle. The global flux of DiMethyl Sulfide(DMS) from the ocean to the atmosphere is shown as an annual mean. Units are of mMol DMS m-2 day-1. The global ocean ecosystem model in POP developed at LANL has been coupled with the air-sea flux parameterization model at ORNL and the flux has been computed. The globally integrated flux of DMS from the ocean to the atmosphere is 23.8 Tg S yr-1, in reasonable agreement with experimentally developed estimates. The high resolution of the ocean DMS maps is evident in the spatial structure of DMS flux. This study required the computational capacity of the Center for Computational Sciences and was supported by the SciDAC CCSM Consortium Project.

4. Carbon and Climate C4MIP SimulationsBiogeochemistry Working Group • Simulations for the Coupled Carbon Model Intercomparison (C4MIP) use active atmosphere and land models with data ocean model and thermodynamic ice run through the coupler. • These cycle through 25 years of forcing data for spin-up and as the spin-up progresses, turn on CO2 flux to the atmosphere with advection. The anthropogenic forcing consists of complete land use change for agriculture and fossil fuel emissions. • The ORNL Cray X1 was the computational platform for these simulations using the CASA’ carbon model (Fung) and CN(Thornton) for intercomparison. The Community Climate System Model (CCSM3) is jointly developed by NCAR and a Consortium of DOE Labs under the SciDAC Program.

5. Building a Coupled Climate-Carbon Model To quantify the feedbacks of the carbon cycle in the climate system and determine the future potential for carbon sequestration new land and ocean ecosystem models are being developed. The figure shows the carbon fluxes from the first U.S. coupled carbon climate model, the PCM-IBIS model.(Geo.Res. Let. 2004). The ocean CO2 flux as the ocean height field. The color overlay indicates the surface concentration of disolved inorganic carbon. Such high volume visualizations allow exploration of the many variables important for understanding feedback mechanisms and the sources of climate variability. Collaboration between ORNL and LLNL for this project was supported by Laboratory Directors Research Funds. Carbon cycle models are now being implemented in the CCSM3 to support on going research sponsored by DOE and in anticipation of future climate change assessments.

6. Porting and Vectorization for CRAY X1 and Earth Simulator • SciDAC Workshop on Vectorization in Feb. 2003 started the effort. • CCSM3 release includes vector mods and is used for IPCC on Japanese Earth Simulator, validated on Cray X1 • Effort spanned NCAR, NASA-Goddard, ORNL, LANL, LBNL, Cray, NEC, Fujitsu, CRIEPI

7. IPCC Fourth Assessment Computational support for IPCC simulations using CCSM3 ORNL Center for Computational Sciences devoted a significant fraction of their resources toward the completion of the IPCC studies. Over the last year, 1.5 million CPU-hours of the IBM p690 computer Cheetah have been dedicated toward the completion of the project. Over 1100 years were simulated using the ORNL computers. The simulation model used is jointly developed by the National Center for Atmospheric Research (NCAR) and a consortium of DOE labs. The SciDAC program of the Office of Science directed the DOE work. A new release of the Community Climate System Model (CCSM3) in June 2004 was specifically designed to provide simulation results addressing the chief scientific questions of the IPCC study.

8. Prototype Coupled Global Carbon-Climate-Chemistry ModelBiogeochemistry Working Group To demonstrate the ability to couple all the software components for coupled climate-chemistry simulations …. DOE SC GG 5.21.3 JOULE Milestone met Sept 2005. http://wwww.scidac.org/BER/BER_CCSM.html

9. Prototype Coupled Global Carbon-Climate-Chemistry ModelBiogeochemistry Working Group • Fully coupled, BGC model integrated for 9 years … • Dynamic vegetation and land carbon pools • Ocean ecosystem and generation of dimethal sulfide • Atmospheric chemistry Link to progress report

10. Coupling Glue for Climate Modeling Frameworks • Extensions of the Component Flux Coupler for Biogeochemistry • Collaboration with ESMF in restructuring CAM • A Single-Executable, Sequential coupling using MPH and MCT • Why scalability requires flexibility • Load balancing strategies in multi-component, massively parallel frameworks Link to further information

11. Cray X1E CCSM Port Validation • Basic tests and configuration • Compiler flags • Vectorization and streaming • Performance of the IPCC configuration

12. Parallel IO Solved! • Parallel NetCDF • CAM solution with ZIOLIB • POP solution from JLeV • Performance and scalability