1. CAM3.5 Model and Intraseasonal Variability Changes
Rich Neale and Jadwiga (Yaga) Richter
MJO Workshop
November 2007

2. Modifications CCSM3->CCSM3.5
Provide the best model for biogeochemistry spin-up
CCMS4 will be very different
Deep Convection
Convective momentum transports (Richter)
Dilute instead of undilute plume calculation (Neale)
Cloud Fraction
Polar cloud freeze-drying (Vavrus)
Calculation update (Park)
Other Model Changes
LAND -New hydrology, surface datasets, canopy integration
ICE – CSIM to CICE
OCEAN – ocean advection scheme
Other Changes
New chemistry modules (GHGs, aerosols)

3. Deep Convection Changes Zhang-McFarlane Scheme (1995)
1. Change from an Undilute to a Dilute Reference Parcel (DIL, Raymond and Blythe, 1986)
Improve diurnal cycle over land
Sensitivity to tropospheric drying
2. Introduction of Convective Momentum Transports (CMT, Gregory et al. 1997)
Include a missing process
Decrease excessive surface trades
Couple convection and dynamics
du/dt = …+d[u’w’]/dz
(dq/dt = …+d[q’w’]/dz)

4. CAM3 + Convection Changes
Annual
Rainfall
Error
CAM3
CAM3 + Convection Changes

5. Annual Surface Stress Error CAM3 + Convection Changes

6. Taylor Diagram of Key Metrics
- Improved mean RMSE by 15%
Annual Cycle of Monthly Means

7. Intra-Seasonal Variance Madden Julian Oscillation (MJO) and Kelvin Waves Deficient OLR (15N-15S)
Observed (NOAA)
CAM3

8. Intra-Seasonal Variance Improvements
CAM3+CONV
CAM3
CAM3+CMT
CAM3
CAM3+DIL
CAM3

9. MJO Variance Winter (November-April)
OLR filtered for MJO wavenumbers (1-5) and periods (30-90days)
Winter (November-April)
Contour interval 20 (W/m2)2

10. MJO Variance Summer (May-October)
OLR filtered for MJO wavenumbers (1-5) and periods (30-90days)
Summer (May-October)
Contour interval 20 (W/m2)2

11. U 850mb
Lag
Correlation
N. Winter
N. Summer

12. Intra-Seasonal Variance CCSM3
CAM3+CONV
CAM3
CCSM3+CONV
CCSM3

13. MJO Variance Winter (November-April)
OLR filtered for MJO wavenumbers (1-5) and periods (30-90 days)
Winter (November-April)
Contour interval 20 (W/m2)2

14. OLR filtered for MJO wavenumbers (1-5) and periods (30-90days)
MJO Variance
OLR filtered for MJO wavenumbers (1-5) and periods (30-90days)
Summer (May-October)

15. U 850mb
Lag
Correlation
N. Winter
N. Summer

16. CCSM3 ENSO nino3

17. Lag 0 Nino 3 SST Correlation
CCSM3
CCSM3 + Convection Changes

18. Lag Regression Lag Correlation w/ Jan Nino3.4 SST’
Obs.
CCSM3
Hendon et al. (2007)
CCSM3 + CONV

19. Taylor Diagram of Key Metrics
- Improved mean RMSE by 10%
Annual Cycle of Monthly Means

20. Summary CCSM3.5 for biogeochemistry experiments
CMT + Dilution changes dominate in the tropics
Reduced excessive trades, improved precip. and mean vertical structure
CAM - improved eastward propagation into Pacific, strong westward propagation remains
CCSM – MJO power closer to observed, increased propagation coherence
MJO disturbances have a significant role to play in improving ENSO, Neale et al. (2007)