Jeffrey T. Kiehl CCSM Scientific Steering Committee Chairman Status of CCSM2 Jeffrey T. Kiehl CCSM Scientific Steering Committee Chairman
Outline CCSM2 Description Status of Control Simulation An Overview of CCSM2 Results with Emphasis on Variability CCSM2 Climate Sensitivity Remaining Challenges
CCSM2 Description CAM2: CCSM Ocean Model Improved Longwave Radiation & Clouds Prognostic Cloud Water Formulation Changes to Convective Precip Increased Vertical Resolution CCSM Ocean Model POP1.4 (with displaced NP into Greenland) Anisotropic horizontal viscosity formulation Increased Horizontal Resolution Revised formulation of G-M Eddy scheme
CCSM2 Description CSIM CLM New Elastic-Viscous-Plastic(EVP) ice rheology New Thermodynamic model, including multi-category ice thickness scheme CLM New biogeophysics formulation Multilayer soil water and T(z) formulation Multilayer snow model with compaction River runoff scheme
Status of Control Simulation Out to year 800, plan to continue simulation to year 1000 Last change made at year 350 (common physical constants) No flux correction applied Model drifts: -0.04 K/century in surface temperature -0.07 K/century in volume avg. ocean T +0.0001 psu/century in volume salinity
Long Terms Trends
CCSM2 Challenges Double ITCZ Excessive Cold Pacific Cold Tongue Excessive Warm Eastern Boundary Water Cold Tropical Tropopause Excessive High Latitude Surface Temperatures
An Overview of CCSM2 Results with Emphasis on Variability
50 17 5.6 2.6 2.1
Tropical Variability
Nino3 SST Power Spectra from CCSM2 & Reanalysis
Polar Climate Variability
Seasonal Cycle Over Land
CCSM2 Climate Sensitivity Started 1% Increase in CO2 at year 220 of Control Implies: 2 X CO2 at Year 70 4 X CO2 at Year 140 Stopped 1% Simulation at Year 370 Carried out Simulation fixed at 2XCO2
Current Thrusts Explore Higher Resolution Atmospheric Model in CCSM2 Continue to Improve Treatment of Cloud in CAM Development of Fully Interactive Carbon Cycle within CCSM Prepare for the IPCC Fourth Assessment
Acknowledgements Thanks to Jay Fein and Dave Bader for their continued support Thanks to the Working Groups for their commitment to the effort Thanks to Lydia Shiver for her support to the CCSM effort