Global ClimateGlobal ClimateModelingModeling
Warren M. WashingtonNCARApril 2000
Global COGlobal CO22 Trend and Rate of Increase Trend and Rate of Increase
Global Methane TrendsGlobal Methane Trends
Snow Cover TrendsSnow Cover Trends
Greenland Ice ThinningGreenland Ice Thinningu Melting in low-lying areas is very rapid
at about 3 feet per year….ScienceMagazine
u Most melting on the southern andeastern parts of Greenland
u Snowfall not changed much…..it is theglaciers moving faster and melting
Expected Changes in theExpected Changes in theEarth’s ChemistryEarth’s Chemistry
u Increased carbon dioxide,methane, nitrogen oxide, loweratmosphere ozone
uDecreased CFCs
u Increased aerosols from fossil fuelcombustion, biomass burning
ParallelParallelClimate ModelClimate Model
(PCM)(PCM)
Laws of Physics inLaws of Physics inClimate ModelsClimate Models
u Conservation of Momentumu First Law of Thermodynamicsu Conservation of Massu Ideal Gas Lawu Hydrostatic Assumptionu Conservation of Water (Vapor and Liquid)u Some models have active atmospheric
chemistry and aerosol physics
PCM Component ModelsPCM Component ModelsuAtmosphere
– NCAR CCM3.2– T42 18 levels– land surface model embedded– SPMD option: 1-D data decomposition (64pe limit)
uOcean– Parallel Ocean Program (POP)– ~2/3 degree horizontal displaced polar grid– 32 levels– 2-D data decomposition
More ComponentsMore ComponentsMore Componentsu Sea ice-viscous-plastic Hibler dynamics with
relaxation, option for elastic-viscous-plastic, 27km resolution, and Parkinson-Washingtonthermodynamics (Zhang, Semtner-NPS;Weatherly-CRREL; Craig-NCAR; Hunke,Dukowicz-LANL)
u Parallel flux coupler (Craig, Bettge, Loft, Dennis,James-NCAR; Jones-LANL)
u River Transport Model (Branstetter, Famiglietti-U. Texas, Austin; Craig-NCAR)
Sequential Executionof PCM
PCM Flux Coupler
CCM3 SeaIce
RiverTransportPOP
ParallelParallelComputersComputers
PCM 1.1 has been run on the following distributedand shared memory systems:
è CRAY T3E900è SGI Origin 2000/128è HP SPP2000è IBM SP2è Sun Starfireè DEC/Compaq Alpha Clusterè Linux Cluster
PCM 1.1PCM 1.12/3o POP
27 km sea ice
T42 CCM3.2
View of the Parallel Ocean Program (POP)Model Horizontal Grid at 2/3o Resolution
Note highresolutionin NorthAtlanticand nearequator.
Numerical MethodsNumerical Methodsu Atmosphere- spherical harmonics, FFT,FD,
Lagrangian, semi-implicitu Ocean-FD, solution of Laplacian equation,
semi-implicit
u Sea Ice-FD
Sequential Executionof PCM
PCM Flux Coupler
CCM3 SeaIce
RiverTransportPOP
Moving from MessageMoving from MessageParadigm to DistributedParadigm to Distributed
Shared Memory ParadigmShared Memory Paradigm
MessageMessagePassingPassing
SharedSharedMemoryMemory
DistributedDistributedSharedSharedMemoryMemory
MPICommunicationbetween PEs
Open MPdirectives withinnode
Open MPdirectives withinnode andmessage passingbetween nodes
Global Atmosphere
Global OceanGlobal Ocean
Sea IceSea Ice
Deep/Abyssal Northwest AtlanticDeep/Abyssal Northwest Atlantic
Regional ClimateRegional ClimateAspectsAspects
u ENSOu Arctic Oscillation
u North AtlanticOscillation
u AntarcticCircumpolarWave
Examples of ClimateExamples of ClimateChange ExperimentsChange Experiments
u Greenhouse gases
u Sulfate aerosols (direct and indirect)
u Stratospheric ozone
u Biomass burning
u Historical simulations
u Various energy/emissions use strategies
Solar VariabilitySolar VariabilitySimulationsSimulations
u In addition to Greenhouse gasesand sulfate aerosol effects
uOne of the ensemble shows aglobal surface temperature changesimilar to the observed record
1860 1880 1900 1920 1940 1960 1980 2000
0.0
0.2
0.4
0.6
-0.2
deg
rees
C
Year
Global Surface Temperature Anomaly
Observed PCM Simulation
1860-1999
Present and Future Emphasisfor Climate Modeling
uMore detailed interactions ofatmosphere, land/vegetation/riverrunoff, ocean and sea ice
uUse of large parallel clusteredcomputer systems
uParadigm -- distant collaborations
ParallelParallelComputersComputers
PCM 1.1 has been run on the following distributedand shared memory systems:
è CRAY T3E900è SGI Origin 2000/128è HP SPP2000è IBM SP2è Sun Starfireè DEC/Compaq Alpha Clusterè Linux Cluster
PCM 1.1PCM 1.12/3o POP
27 km sea ice
T42 CCM3.2
DOE/UCAR ParallelClimate Model Project
IBM/SP O2K300
Need Help from AppliedNeed Help from AppliedMathematics CommunityMathematics Community
u Remappingu Laplacian solver on cluster computer systemsu Global sums, fast FFTsu Re-coding for distributed cluster computers
systemu Better use of cachesu Improved numerical methods for atmosphere,
ocean, sea ice, and hydrological system
Distributed InvolvementDistributed InvolvementDOE and NSF Supported Project withDOE and NSF Supported Project with::
uu Los Alamos National LaboratoryLos Alamos National Laboratoryuu National Center for Atmospheric ResearchNational Center for Atmospheric Researchuu Naval Postgraduate SchoolNaval Postgraduate Schooluu Oak Ridge National LaboratoryOak Ridge National Laboratoryuu University of Texas, AustinUniversity of Texas, Austinuu Scripps Oceanographic InstituteScripps Oceanographic Instituteuu DOE Program on Climate Diagnostics and IntercomparisonDOE Program on Climate Diagnostics and Intercomparisonuu U.S. Army Cold Regions Research and EngineeringU.S. Army Cold Regions Research and Engineering
LaboratoryLaboratoryuu National Energy Research Supercomputer CenterNational Energy Research Supercomputer Center
Animation CreditsAnimation Creditsu The atmospheric animation was from the
Community Climate Model at T170 resolution.This model was developed by the NCAR ClimateModeling Section. The graphics were preparedby Don Middleton of NCAR.
u The ocean animation makes use of the LANLPOP model and was prepared by the scientists atthe Naval Postgraduate School (NPS)
u The sea animation uses the Zhang model of theNPS.
The EndThe End
More information can be found athttp://www.cgd.ucar.edu/ccr/pcm/