Humidity impact on the aerosol effect in warm cumulus clouds

The effects of aerosols on clouds are recognized as among the most important factors affecting climate change yet these effects are poorly understood due to the complexity of cloud processes and the strong influence of other environmental conditions. A numerical cloud model is used here to study the combined influence of aerosol concentration and upper level humidity conditions on moderate-sized, coastal, convective clouds. We show that these variables are strongly linked in their effects on clouds and suggest a microphysical variable space in which their influence can be distinguished.