1. Relationship Between Cloud Droplet Effective Radius and Cloud Top Height for Deep Convective Clouds in CloudSat Data Product Satoshi Suzuki, Shinta Seto, and Taikan Oki Institute of Industrial Science, the University of Tokyo

2. Background: Aerosol Convection Invigoration Effect Hypothesis Rosenfeld et al. (2008)

3. Background: Aerosol Convection Invigoration Effect Hypothesis Aerosol concentration Cloud droplet radius Cloud top height Ex) Nakajima et al. (2001) Purpose: Examine Cloud droplet radius - Cloud top height relationship Ex) Koren et al. (2010)

4. Data: CloudSat 2B-CWC-RVOD (Dec. 2006-Feb. 2007) Cloud Top Height >5000m Cloud Base <1500m 50km (Independent data) Cloud top height: highest bin with value Cloud droplet effective radius (liquid only) Cloud droplet effective radius↓ Convection↑ Cloud top height↑ Conditions of the clouds to be analyzed

5. Geographical Distribution of Clouds Matching the Condition Cloud top height [m]

6. Average profile for each cloud top height

7. Average profile for each cloud top height

8. Cloud droplet effective radius - Cloud top height relationship Cloud droplet effective radius↓ Cloud top height↑

9. Radar Reflectivity Factor and Cloud Top Height Radar reflectivity is lower for lower clouds => correct attenuation calculation is needed for the negative relationship to appear

10. Droplet Radius – Cloud Top Height Relationship for clouds without precipitation flag (dBZe<-15) Significant negative correlation still appears

11. Variation of the relationship by surface temperature Rosenfeld et al. (2008) suggested freezing causes clouds to become invigorated. Freezing Level Invigoration No Invigoration Low Invigoration High Temperature Low Temperature

12. Variation of the relationship by surface temperature Cloud top >5000m ⇓ >1600m Cloud base < 1500m ⇓ <1000m 50km (Independent data) Cloud top height Cloud droplet effective radius To see the effect of freezing, lower clouds are also included in the analysis. Freezing Level

13. Lower clouds do not show negative correlation Cloud droplet effective radius - Cloud top height relationship

14. Surface temperature 30 – 40 deg C No negative correlation

15. Surface Temperature 10 – 20 deg C Negative correlation appears in clouds with lower cloud top heights Freezing Level

16. Surface Temperature 0 – 10 deg C By moist adiabatic lapse rate, in most cases, altitude of 2000m should be below 0 deg C A mechanism other than freezing? Freezing Level

17. Another Hypothesis by Lee et al. (2010) Higher aerosol concentration Smaller Cloud droplet effective radius (Larger surface area) Larger Evaporation rate Stronger downdraft, gust front Stronger Convection

18. In clouds with cloud top heights lower than 3000 m, gust fronts do not form?

20. Thank you for your kind attention! The authors would like to acknowledge the CloudSat Data Processing Center at CIRA/Colorado State University for providing data products, Environment Research and Technology Development Fund (S-8) of the Ministry of the Environment, Japan, KAKENHI(22760365), JSPS, Japan, and IGARSS 2011 for their support to this work and presentation.