Aerosol-Cloud Interactions
Graham Feingold
Clouds come in all shapes and sizes
Cumulus “ominous” Trade Cumulus Warm Continental Cumulus Actinoform Clouds Cumulus Humilis (John Day)
Closed and Open Cells (Garay et al. 2003)
Aerosol Enhances Cloud Brightness
Ship track Images, Aqua, MODIS
Clouds as Generators of Rain
Micron-size drops to mm-sized drops in ~ 20 minutes
10 orders of magnitude change in mass!
Aerosol particles (~ m in size) play a role!
Aerosol Modifies Precipitation• Evidence for suppression in individual warm clouds• Deep convective clouds are more complex
precipitatingNon-precipitating
Small dropsassociated withpollution
Rosenfeld, 2000
Aerosol Suppresses Cloud: The Absorption Effect
Columbia shuttle imageAmazon
smoke
clouds
clouds
Cloud Models
• Demonstrate fundamentals of drop activation and growth in a cloud parcel model
• Discuss results from 3-D models of aerosol-cloud interactions
12 km12 km
Hei
ght,
m