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The Community Climate System Model. Bill Collins Chair, CCSM Scientific Steering Committee National Center for Atmospheric Research Boulder, Colorado. Applications of CCSM Development of new version of CCSM Features of CCSM simulations Future improvements in CCSM - PowerPoint PPT Presentation
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CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
The Community Climate System The Community Climate System ModelModel
Bill CollinsChair, CCSM Scientific Steering Committee
National Center for Atmospheric ResearchBoulder, Colorado
• Applications of CCSM• Development of new version of CCSM• Features of CCSM simulations• Future improvements in CCSM• Computational demands for new science
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Structure of CCSM
Atmosphere(CAM)
Ocean(POP)
Coupler(CPL)
Sea Ice(CSIM)
Land(CLM)
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Component Models in CCSM
• Atmosphere– Multiple dynamical cores: SLD, Eulerian, & Finite Volume– Generalized 2D decomposition of grid– Resolutions with most heritage: T31, T42, and T85 (L26)
• Ocean– Derivative of LANL Parallel Ocean Program – Grid: spherical in S. hemisphere, orthogonal curvilinear in N.
hemisphere– Standard resolution: 320 x 384 (L40)
• Land Surface– Superset of NCAR LSM and Georgia Tech BATS– Same horizontal resolution as atmosphere– 10 layers for soil, up to 5 for snowpack
• Sea Ice– Up to 5 categories of sea-ice thickness
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Organization of CCSM Project
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Utilization of CCSM
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Simulation of Recent Climate
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CCSM2 – Holocene Climate
CCSM2
Kohfield and Harrison, 2000
Annual Precipitation Change8.5 ka minus Present
mm/year
• PMIP models underestimated both the north-ward shift and magnitude of the precipitation increase required to maintain lakes and vegetation. • CCSM2 more realistically simulates rainfall increases between 20-25°N latitude• CCSM2 still underestimates needed rainfall along the Mediterranean and in South Africa.
Collaborators: PARCS, PMIP
For the mid-Holocene, lake levels, plant macrofossil, and pollen data indicate a greener Sahara.
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CCSM2 – Last Interglacial Climate
Dye 3
Renland
Camp Century
GRIP
CCSM2
• CCSM2 forced with anomalous seasonal solar insolation associated with orbital changes warms the Arctic climate.
• For summer, Arctic sea ice decreases significantly and Greenland warms by 1-5oC.
• Terrestrial data sites warmed rapidly and early; most by 4-6oC.
• Greenland ice cap melted except for summit.
JJA Surface Temperature130 ka minus Present
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CCSM2 Improvements for Paleoclimate
• River runoff scheme• New sea-ice model• Free surface ocean &
prognostic cloud water in the atmosphere
• Grid and ocean/land mapping capability for any past time period
Bathymetry and land mask editing tool eCubed. [John Davis and Rick Smith (LLNL); Walter Voit (UT Dallas)]
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
El Nino Simulations for Current Climate
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Predicting Co-evolution of CO2 and Climate
Atmospheric GCMPrognostic CO2
Ocean GCM+ BGC
Biophysics+ BGC
Fossil FuelCO2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Ongoing Development of CCSM
CSM 1.0
CCSM 2.0
New ocean, land, sea-ice models New physics in atmosphere
June 1996
May 2002
CCSM 3.0
New physics in all models
Winter 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Main Model Biases in CCSM2
Double ITCZ and extended cold tongue Cold tongue mitigated in new POP, double ITCZ in new CAM
Overestimation of winter land surface temperatures Bias largely eliminated in new CLM and CAM
Underestimation of tropical tropopause temperatures Bias reduced in new CAM
Erroneous cloud response to SST changes Signs and pattern of response corrected in new CAM
• Errors in E. Pacific surface energy budget Overestimation of insolation larger in prototype
• Underestimation of tropical variability Underestimation still present
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Double ITCZ
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Winter Land Surface Temperatures
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Tropical Tropopause Temperatures
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Cloud Forcing Response to Tropical SSTs
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
East Pacific Surface Energy Budget
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Tropical Variability
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Ocean Model Changes for CCSM 3.0
• KPP boundary layer • Double Diffusion• Solar Absorption (Chlorophyll)• Ideal Age and Passive Tracer
Infrastructure• Ocean Currents in Air-Sea Fluxes
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CONTROL All Physics + Numerical MODS
Jan
July
Mixed Layer Depths
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
SST Signature of Solar Absorption
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
SST Signature of All Ocean Modifications
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Goal For CCSM2: state-of-the-art model with focus on biogeophysics, hydrology, river routing
Goal For Next Few Years: Natural and human-mediated changes in land cover and ecosystem functions and their effects on climate, water resources, and biogeochemistry
Process: Continue to develop and improve existing physical parameterizations in the model while adding new biological and chemical process
Land Model Working Group
Hydrology
Drainage
Canopy Water
Evaporation
Interception
SnowMelt
Sublimation
ThroughfallStemflow
Infiltration Surface Runoff
Evaporation
Transpiration
Precipitation
Soil Water
Redistribution
Direct Solar
Radiation
Absorbed SolarRadiation
Diff
use
Sol
ar
Rad
iatio
n
Long
wav
e R
adia
tion
Reflected Solar Radiation
Em
itted
Lon
g-w
ave
Rad
iatio
n
Sen
sibl
e H
eat
Flu
x
Late
nt H
eat
Flu
x
ua0
Momentum FluxWind Speed
Soil Heat Flux
Heat Transfer
Pho
tosy
nthe
sis
Biogeophysics
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Biogeochemistry
Goal: Enable parameterization of terrestrial carbon cycle
• New hierarchical data structures within a grid cell: grid cell land unit snow/soil columns plant functional types. Does not change climate.• Allow multiple plant types on a single soil column. Minor climate changes.
Biogeophysics I
Goal: Minor changes or bug fixes
• Allow precipitation to be rain/snow mix • Improve 2-m temperature diagnostic • Remove discontinuity in bulk density of snow
Biogeophysics II
Goal: Reduce excessive summertime temperatures in arid regions. Reduce Arctic winter warm temperature bias
• Turbulent exchange of heat from ground
Model Development for new CLM
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Increased Turbulent Heat Flux from Vegetated SurfacesCLM2.2 CLM2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Effects on Land Surface Temperatures
• 22-year (1979-2000) simulations of CAM2 with CLM2.2• CLM2.2 significantly cools surface air temperature
CLM2.2 CLM2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Changes to Physics in CAM3
• Clouds and condensate:Clouds and condensate:– Improved prognostic cloud water & moist processes – Transfer of mixed phase precipitation to land surface– Improved cloud parameterization
• Radiation:Radiation:– Shortwave forcing by diagnostic aerosols – Updated SW scheme for H2O absorption– Updated LW scheme for LW absorption and emission
• Surface models:Surface models:– Introduction of CLM 2.2– Reintroduction of Slab Ocean Model (SOM)
• Energy fixers for dynamics + diagnosticsEnergy fixers for dynamics + diagnostics
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Increased Cloud Condensate
• Separate cloud liquid and ice variables• Advect cloud condensate• Include latent heat of fusion• Use ice & water variables for cloud optics• New dependence on temperature for cirrus particle size• Sedimentation of cloud droplets and ice particles• Modified evaporation of rain
CAM 2CAM 3
CAM 3 – CAM 2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Increased Cloud Amounts
• PBL height constrained• Rain rate > 0• Convection cloud amounts from convective mass fluxes• Stratocumulus clouds in lowest 2 levels• Changes to autoconversion thresholds• Changes to relative humidity thresholds• Fall speed of droplets is function of effective radius
NETTOA = 4.5 Wm2
NETTOA = 0.53 Wm2
CAM 2CAM 3
CAM 3 – CAM 2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Global Aerosol Assimilation Climatology
Analysis NCAR CAMAerosol ForcingClimate Impacts
AVHRRAerosol Assimilation
Analysis
1995-2000
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Addition of Prescribed Aerosol Forcing
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Changes in Longwave Cooling Rates:New H2O Lines and Continuum
Change in LBL Cooling
Change in CAM Cooling
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Global Decrease in Longwave Fluxes
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Changes in Shortwave Heating Rates:New H2O Lines and Continuum
LBL Heating
CAM2 Heating
CAM2x Heating
Tropics
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Global Increase in SW Heating Rates
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Global Decrease in Surface Insolation
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Higher Tropopause Temperatures
CAM 2CAM 3
CAM 3 – CAM 2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Lower Winter Land Surface Temperatures
CAM 2CAM 3
CAM 3 – CAM 2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Cloud Response to Tropical SST Variations
CAM 3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Cloud Radiative Forcing during ENSOs
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Changes in Precipitation
CAM2/CLM2 CAM3/CLM2.2
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Changes in Coupler & the Sea-Ice Model
• Coupler– Improved performance and scaling– Greater flexibility to add new fields– Significant DOE communication infrastructure– Faster multi-way communication to
components
• Sea Ice– Horizontal advection scheme– Addition of constant salinity in sea ice– Updates to albedos of snow and sea ice– Updates to ridging for thick ice categories
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Global Energy BalanceControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Land Surface TemperaturesControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Ocean Surface TemperaturesControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Surface Wind StressControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Surface InsolationControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Sea-Ice ExtentControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Sea Ice Area and VolumeControl Integration of CCSM3
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Climate Sensitivity of CCSM
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Development Plans for CCSM, 2004-08
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Development Plans for CCSM, 2004-08http://www.ccsm.ucar.edu/management
• CCSM Science Plan– Brief history of the CCSM program– Scientific accomplishments of CCSM2– Status of the CCSM– Planned climate experiments– Near-term program for understanding coupled model– Scientific questions needing major new capabilities
• CCSM Business Plan– Current resources– Vision for the future and resource requirements
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CCSM: The Next Two Years
• Roadmap to the future– Climate sensitivity from IPCC studies– Process studies from GFDL collaboration, CPTs– Studies of higher resolution and
“benchmark” calculations– News physics/dynamics from Science Plan
• Integration of climate and chemistry– Ocean and land biogeochemistry– Prognostic aerosols– Tropospheric chemistry– WACCM– Tracers
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
The Evolution of CCSM
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
New Physics for High Resolution:Reduced Lateral Viscosity
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Computational Demands for CCSM Science
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
CAS2K3 Meeting, AnnecySeptember 8-11, 2003
Challenges
• Atmosphere– Convection– Cloud/radiation interactions– Incorporation of atmospheric chemistry
• Ocean– Eddy-resolving resolution– Mesoscale modeling of coastal zones
• Land– Urban land use change– Prognostic biogeography
• Sea Ice– Surface complexity on scales << grid spacing