Aerosol effects on clouds and climate (Invited Presentation)

Aerosol particles act as cloud condensation and ice nuclei and with that determine the microstructure of clouds. Due to anthropogenic emissions the abundance of sulfate and carbonaceous aerosol particles has been increased. This causes water clouds to have on average more and smaller cloud droplets and to reflect more solar radiation back to space. Changes in the number and size of ice crystals changes are much more uncertain because of competing mechanisms and fewer observations. In my talk I will therefore concentrate of the aerosol radiative forcing associated with clouds containing ice.