1. Cloud, radiation, and precipitation changes with dynamic regime: An observational analysis and model evaluation study PI: George Tselioudis Co-PI: Chris Weaver-Bill Lapenta Co-Is: Michael Bauer, Christian Jakob Collaborator: Anthony DelGenio

2. Proposal goals What are the main regimes of variability of midlatitude cloud, radiation, and precipitation fields and what is their relationship to the large-scale atmospheric dynamics? What are the model deficiencies in simulating midlatitude cloud. Radiation, and precipitation properties and how do they affect the model climate sensitivity? How does subgrid-scale (defined with respect to a GCM) variability of atmospheric dynamics, in particular vertical motion, affect cloud, radiation, and precipitation properties in midlatitude clouds? What is the relationship between the subgrid dynamical and thermodynamical processes that control these subgrid cloud, radiation, and precipitation distributions and the resolved-scale variables on the GCM grid?

3. Proposal tools Observations: Global satellite cloud, radiation, and precipitation datasets Models: Climate model (GISS), regional model (WRF) Analysis techniques: Clustering, compositing Methodology Apply analysis techniques to observations and model output and pray that useful information will emerge to help us evaluate and improve models and reduce model range of sensitivity

4. ISCCP Clusters 15S-15N Rossow et al. 2006

5. GCM clusters Tropics Williams and Tselioudis 2006

6. GCM Cluster Properties Tropics

7. ISCCP Clusters 30-60N

8. GCM Clusters Extra-Tropics

9. GCM Cluster Properties Extra-Tropics

10. 2xCO2 Cloud Radiative Forcing change What if the models simulated the observed current-climate clusters? Climate sensitivity range would be reduced by 30%

11. Why use Regional Models? Flexible tool that covers both case- study and statistical ensemble timescales and can be run at both GCM and CRM resolutions

12. Regional model runs at different resolutions can help us relate subgrid scale processes to the resolved-scale variables on the GCM grid? 3-km REGIONAL Model runs

13. CMAI Deliverables  Observational Clusters and Composites (DIME)  Model clusters and composites (DIME)  Clustering Software (DIME)  GCM evaluation metrics based on cluster properties  Assistance to any GCM group brave enough to want to test their model against observational clusters/composites

14. ECMWF GCM T106 APRIL LAND 30-60N * GCM is missing 19% cloud cover in the W-DN regime * GCM clouds are too optically thick in all regimes * GCM is missing middle and low thin cloud in al regimes Tselioudis and Jakob 2002

15. * GCM clouds are too optically thick * GCM is missing middle and low thin cloud Regional model ARM SGP PC-TAU composites Month-long regional model SGP runs show similar patterns