1. Status of CAM, March 2004 Phil Rasch

2. Differences between CAM2 and CAM3 (standard physics version) Separate liquid and ice phases Advection, sedimentation of condensate Rain and snow are carried explicitly Latent heat of vaporization Convective cloud fraction Floor on PBL height Ice crystal size temperature dependent Radiation and microphysics see same cloud properties (except drop radius) Remapping of Klein/Hartmann clouds to sea level pressure Change in snow/ice albedo over sea ice Pristine/polluted cloud regime definitions changed –Smooth rapid transition in polar regions –Always pristine over sea ice –Always pristine with significant snow cover Detrainment of condensate from Shallow/frontal convection New aerosol climatology Revised radiative transfer calculation (clearsky, clouds, aerosols)

3. new features Prognostic sulfur cycle Slab Ocean Model SOM Prognostic greenhouse gases Explicit support for FV and SLD cores for standalone runs “wet” and “dry” mass mixing ratios –Revisions to mass fixer (dry only)

4. Reduction or elimination of these problems –Cold tropical tropopause –Warm polar climate –Warm summertime extratropics –Energy conservation (involving latent heat of fusion) –Upper troposphere clouds turn on and off in a single time step

5. Current tuned versions T85, T42, T31 standalone and coupled eulerian (spectral simulations) 2x2.5 FV simulations 100+ year simulation of coupled FV model shows a bias that requires more thought

6. Uncoupled FV vs T85 Ps

7. Uncoupled Residual energy flux at the surface

8. Coupled FV vs T85 --- year 90

9. Other interesting configurations not ready for prime time Semi-Lagrangian Dynamics (T85 is current focus) Higher and lower horizontal resolutions Numerous experimental configurations you will hear more about during the meeting. (aerosols, isotopes, PBL, shallow Cu, …)

10. Between now and June Complete code modifications Complete documentation Complete runs required to document the model Write papers characterizing models

11. J. Climate Papers (subject to revision) CAM overview CSM atmosphere compared to CAM Impact of changes in moist physics on model state (piece by piece) Hydrologic cycle mean state Hydrologic cycle transient aspects Dynamic circulation of “base model” Dynamic core impact on transport processes Circulation sensitivity to Dynamical core Slab Ocean Model Circulation sensitivity to resolution Climate Sensitivity Preindustrial, present, future changes in forcing, and model response (standalone atm and SOM)

12. Simulations being used to evaluate the model Coupled (multi-century) –1990 T85Atm-1xOcn –1990 T42Atm-1xOcn –1990 T31Atm-3xOcn –1990 FV2x2.5Atm-1xOcn Slab Ocean Model (40-50 year simulation) –1990 T85, T42, T31, FV –Doubled CO2 T85, T42, T31, FV –T42, preindustrial and future forcing CAM standalone –Eulerian, T85, T42, T31, FV2x2.5 (AMIP) –Eulerian, T85, FV2x2.5 (climatological SST) 10-20 year tracer simulations –Eulerian, T85, T42, SLD T85, FV2x2.5

13. Temperature Bias (Control Model – ECMWF) DJF JJA

14. Surface Temperature Bias (land)

15. Changes to Ice Water Content DJF JJA New model control

16. Liquid Water JJADJF New model control

17. Temperature Change (revised – control) DJFJJA

18. Tropical Tropopause Temperatures CAM 2 CAM 2.X

19. Modifications to high cloud cover

20. Modifications to low cloud cover DJF JJA

21. Cloud Liquid Water path

22. Low Cloud Fraction SWCF LWCF

23. SWCF LWCF

24. Zonal Average Clouds Low Mid-level High

25. Zonal Average Condensate mixing ratio