1. Improved Climate Simulations with Modified Convection Scheme: What’s Next? Xiaoqing Wu (ISU) and Guang Jun Zhang (SIO) Supported by DOE CCPP, ARM and NSF Xiaoliang Song and Liping Deng (ISU) Guido Vettoretti and W.R. Peltier (UT)

2. Modified Zhang-McFarlane (ZM) Convection Scheme Revised convection closure assumption Convection is tied to the destabilization of the tropospheric layer above PBL by the large-scale processes Trigger condition of deep convection Convection is activated when the relative humidity is larger than certain threshold, or the increase of CAPE due to the large-scale processes exceeds certain threshold Convective momentum transport Convection redistributes the horizontal momentum through the compensating subsidence, detrainment and perturbation pressure gradient

3. Detrainment of excess momentum from clouds Subsidence of environmental air that compensates the cloud mass flux Zhang and Cho (1991, JAS) Wu and Yanai (1994, JAS) Wu, Zhang and Liang (2003, GRL) Convective Momentum Transport (CMT) Cloud-scale pressure Cloud mass flux Detrainment of mass In-cloud momentum Convective momentum tendency Fractional area of clouds Convection-induced pressure gradient force

4. CAM3 Spectral CCSM3 (T31) CCM3 Spectral CSM1.4 (T31) CAM3.3 FV CCSM3.1 Atmospheric ModelsFully Coupled Models

5. Double ITCZ problem CSM1.4 with modified ZM CCSM3 with modified ZM

6. Seasonal variation CSM1.4 with modified ZM CCSM3 with modified ZM

7. Variability Diagnostics for 6-Hourly Data CAM3.3 FV

8. Standard CAM3CAM3 with revised closure and rh=0 CAM3 with revised closure and rh=0.8CAM3 with modified ZM Variability Diagnostics for 6-Hourly Data

9. CAM3.3 FV isufvcam6 cam_fvz Histograms of daily precipitation rate

10. Standard CAM3 CAM3 with revised closure and rh=0 CAM3 with revised closure and rh=0.8CAM3 with modified ZM Histograms of daily precipitation rate

11. MJO cam3_3_fv_1.9x2.5 isufvcam6 cam_fvz

12. NCEP MJO CCSM3 with modified ZM Standard CCSM3 CCSM3.1 with modified ZM b31.007 (years 79-98)

13. ENSO b31.001b31.006b31.007

14. Standard CSM1.4CSM1.4 with modified ZM ENSO

15. Standard CCSM3CCSM3 with modified ZM ENSO

16. Deser et al. (2006, JC)