A DNS study of aerosol and small-scale cloud turbulence interaction
Abstract. The purpose of this study is to investigate the effect of aerosol dynamics (evaporation/condensation) on atmospheric small-scale turbulence (and vice versa) using direct numerical simulations (DNS). We consider the domain located on the height of about 2000 m from the sea level, experiencing transient high supersaturation due to atmospheric fluctuations of temperature and humidity. To study the effect of aerosol dynamics on the turbulence we vary the total number of particles (Ntot). In turn, to investigate the effect of small-scale turbulence on evolution of aerosol particles we vary the intensity of turbulent fluctuations and the buoyant force. We find that even small amount of aerosol particles (55.5 cm−3) increases the air temperature by 1 K under supersaturated conditions due to release of latent heat. The system comes to an equilibrium faster and the relative number of activated particles appears to be smaller for larger Ntot. We conclude that the presence of aerosol particles results in deceleration of air motion in vertical direction and damping of turbulent fluctuations.