Numerical simulations of stratocumulus cloud response to aerosol perturbation

• The albedo may increase directly in response to additional aerosol in the boundary layer.
• The magnitude of the increase depends on the microphysical properties of the existing cloud.
• For clouds characterized by high cloud droplet number, seeding may lead to the decrease in albedo.

In this paper results from the 2D numerical model with Lagrangian representation of microphysics are used to investigate the response of the radiative properties of stratocumulus as a result of adding aerosol within the boundary layer. Three different cases characterized by low, moderate and high cloud droplet number and for 3 sizes of additional aerosol 0.01 μm, 0.1 μm and 0.5 μm are discussed. The model setup is an idealization of one of the proposed Solar Radiation Management methods to mitigate global warming by increasing albedo of stratocumulus clouds. Analysis of the model results shows that: the albedo may increase directly in response to additional aerosol in the boundary layer; the magnitude of the increase depends on the microphysical properties of the existing cloud and is larger for cloud characterized by low cloud droplet number; for some cases for clouds characterized by high cloud droplet number seeding may lead to the decrease in albedo when too large radius of seeding aerosol is used.