Aerosol Effect on Cloud Droplet Size Monitored from Satellite
Francois-Marie Bréon,1*
Didier Tanré,2
Sylvia Generoso1
Aerosol concentration and cloud droplet radii derived from
space-borne measurements are used to explore the effect of aerosols on
cloud microphysics. Cloud droplet size is found to be largest (14 micrometers) over remote tropical oceans and smallest (6 micrometers) over highly polluted continental areas. Small droplets are also present
in clouds downwind of continents. By using estimates of droplet
radii coupled with aerosol load, a statistical mean relationship is derived. The cloud droplet size appears to be better correlated with
an aerosol index that is representative of the aerosol column number
under some assumptions than with the aerosol optical thickness. This
study reveals that the effect of aerosols on cloud microphysics is
significant and occurs on a global scale.
1 Laboratoire des Sciences du Climat et de
l'Environnement, Commissariat à l'Energie Atomique, Gif sur
Yvette, France.
2 Laboratoire d'Optique
Atmosphérique, CNRS, Université des Sciences et
Technologies de Lille, Villeneuve d'Ascq, France.
*
To whom correspondence should be addressed. E-mail:
fmbreon{at}cea.fr
