AMWG Meeting April 3-4, 2002 Overview of CAM status and simulations Bill Collins and Jim Hack National Center for Atmospheric Research Boulder, Colorado Update on model status, simulations, and release Computational performance of CAM Features of model simulations

AMWG Meeting April 3-4, 2002 Topics Overview of status and analysis of CAM Discussion of new diagnostic efforts Discussion of new physics parameterizations Update on extensions to model Overviews of work on isentropic coordinates by other modeling groups Open discussion Objectives for summer workshop

AMWG Meeting April 3-4, 2002 Agenda Tue 1:00 PMCollins / HackOverview of CAM simulation 1:45 PMTaylor et alComparative assessment of climatology New 2:10 PMBoylePNA and stationary wave patterns 2:20 PMDiscussion 2:30 PMBitz et alHigh latitude climate in CAM and CCSM 3:15 PMMaloneyConvective variability for eastern Pacific 3:45 PMSun et alRadiative & dynamical feedbacks in CAM 4:00 PMRaschModifications to prognostic H 2 O scheme 4:10 PMZhang et alNew formulation for stratiform cloudiness Wed 9:00 AMStephens et alEffects of new radiation parameterization 9:30 AMKhairoutdinovTests of a super-parameterization 9:50 AMSassiWACCM 10:10 AMBovilleHeating and kinetic energy dissipation 10:45 AMKonorGeneralized vert. coord. model at UCLA 11:30 AMRandallOverview of isentropic coord. work at CSU 1:30 PMDiscussion

AMWG Meeting April 3-4, 2002 Developments since June 2001 Workshop Conducted first coupled simulations Implementation/restructuring implementation of new CAM design: –parameterization interface –creation of constituents module addition of new ESMF time-manager continued work on splitting dynamics and physics incorporated “chunking” data structures (2D decomposition) other ongoing implementation changes –shared constants, file naming conventions, etc.

AMWG Meeting April 3-4, 2002 Developments since June 2001 Workshop Major modifications/improvements: Fractional surface specification implemented and validated l works properly for all three dynamical cores l introduces minor simulation changes CSIM ice thermodynamics implemented and validated specified and prognostic snow cover implemented and evaluated slightly colder ice temperatures reasonable seasonal cycle in snow cover

AMWG Meeting April 3-4, 2002 Developments since June 2001 Workshop Numerous “minor” modifications/improvements: l Minghua Zhang prognostic cloud-water closure modification l vertical diffusion on dry static energy l update static energy instead of T between parameterizations l modifications required for coupled simulations –changes to cloud drop number concentration over sea ice –changes to methodology for determining rain vs. snow l other changes required for middle-atmosphere configuration creation of final boundary datasets –SST and sea ice concentration

AMWG Meeting April 3-4, 2002 Upcoming Papers on CAM General overview New sea-ice formulation Finite volume dynamical core Parameterization for statiform fractional cloudiness New H 2 O longwave and cloud overlap Hydrometeor evaporation mechanism New global SST climatology Fractional ice and land Coupling of parameterizations with dynamical core Heating and kinetic energy dissipation Tracer transport

AMWG Meeting April 3-4, 2002 Release of CAM to Community CAM 2.0 and CCSM 2.0 will be released May 17 (’02) Contents of release: –Model component source code; build and run scripts Eulerian –Three dynamical cores: Eulerian, semi-Lagrange, and Finite Volume –Web-based documentation User’s Guide (how to run the model) Reference Guide (details of the code structure) Scientific Guide (description of physics and dynamics) –Initial and boundary data sets New SST and sea-ice concentration data –Model data sets: AMIP-2 and climatological SST uncoupled integrations (Eulerian dynamics)

AMWG Meeting April 3-4, 2002 Computational Performance Supported platforms: –Compaq –IBM-SP –Linux: Portland group and Lahey compilers –SGI –Sun Performance: –1 month per 32 wall-clock minutes on 32 IBM Power3 Pes –Equivalent to ~4 years per wall-clock day on same setup –Reduced grip speed-up: 25-30% (Eul. & SLD uncoupled only)

AMWG Meeting April 3-4, 2002 TOA Energy Components Fractional Land/Sea Ice vs “Integer” Representation

AMWG Meeting April 3-4, 2002 Surface Energy Components Fractional Land/Sea Ice vs “Integer” Representation

AMWG Meeting April 3-4, 2002 Surface Energy Fluxes Fractional Land/Sea Ice vs “Integer” Representation Latent Heat Flux Precipitation Rate

AMWG Meeting April 3-4, 2002 Surface Temperature CSIM Thermodynamic Ice vs “Old” Ice Thermodynamics

AMWG Meeting April 3-4, 2002 Surface Temperature CSIM Thermodynamic Ice vs “Old” Ice Thermodynamics

AMWG Meeting April 3-4, 2002 New Blended SST-Sea Ice Concentration Data Completed in collaboration with CVWG blending technique developed by Jim Hurrell –blends HadISST with Reynolds screening technique to ensure reasonable SST-sea ice relationship PCMDI procedures for ensuring correctness of time interpolation extensive quality control procedures Fifty-three year dataset ( ) l can easily be extended as new SST data are created by NCEP l currently have completed 21 year control experiment ( )

AMWG Meeting April 3-4, 2002 Southern Oscillation Index

AMWG Meeting April 3-4, 2002 Southern Oscillation Index

AMWG Meeting April 3-4, 2002 Sea Ice, Snow Height, and Precipitation Rate Fractional Land/Sea Ice, CSIM Thermodynamics, New SST

AMWG Meeting April 3-4, 2002 General Simulation Properties/Framework Scientifically defensible & extendible framework spectral Eulerian dynamics (reduced-grid capable) T42 truncation 26 levels prognostic cloud water generalized cloud overlap (plus requisite changes to LW & SW) updated long wave water vapor absorption formulation modified deep convection parameterization

AMWG Meeting April 3-4, 2002 General Simulation Properties/Framework Improvements in several important simulation features precipitable water precipitation distribution eastern ocean solar energy budget elements of eastern Pacific surface wind stress Degradations in simulation features colder troposphere, particularly the tropical tropopause tendency for more zonal double-ITCZ structure warm surface temperature bias?

AMWG Meeting April 3-4, 2002 Temperature (coupled framework)

AMWG Meeting April 3-4, 2002 Surface Temperature (coupled framework)

AMWG Meeting April 3-4, 2002 Precipitable Water (coupled framework)

AMWG Meeting April 3-4, 2002 Precipitable Water (coupled framework)

AMWG Meeting April 3-4, 2002 Precipitation Rate (coupled framework)

AMWG Meeting April 3-4, 2002 Surface Stress (coupled framework)

AMWG Meeting April 3-4, 2002 Net Longwave Surface Fluxes (coupled)

AMWG Meeting April 3-4, 2002 Net Surface Energy Flux (coupled)

AMWG Meeting April 3-4, 2002 Surface Temperature (against obs)

AMWG Meeting April 3-4, 2002 Eastern Pacific Surface Stress

AMWG Meeting April 3-4, 2002 E. Pacific Surface Stress: Resolution Dependence?

AMWG Meeting April 3-4, 2002 Future Work Begin ensemble of ~50 year long control simulations conducted in coordination with Climate Variability Working Group –will serve as the basis for documenting simulation characteristics Accelerate exploration of alternative dynamical frameworks T31 paleo configuration (update for fractional surface formulation) T85 configurations (Eulerian and semi-Lagrangian for now) continued evaluation of simulations with finite-volume dynamical core Begin systematic investigation of specific simulation biases AMWG should identify short list of prioritized projects –eastern ocean upwelling, double ITCZ, cold tropopause temps,... –climate sensitivity, variability (e.g., MJO),... form teams to develop comprehensive scientific plan of attack –experimental strategy –diagnostic strategy

AMWG Meeting April 3-4, 2002 Future Work AMWG research infrastructure –needs to be able to support research activities on multiple fronts boundary layer dynamical cores stratiform clouds middle atmosphere (e.g., WACM) radiation parameterization alternatives cumulus parameterization alternatives AMWG diagnostic infrastructure –needs to continue to grow in scope and complexity evaluate model behavior across wide range of time scales include dominant modes of climate variability in standard analysis –continued involvement of other CCSM working groups