Certain air-borne bacteria have been recognized as active ice nuclei at the temperature warm than -10oC.Ice nucleating bacteria commonly found in plants and ocean surface.These ice nucleating bacteria are readily disseminated into the atmosphere and have been observed in clouds and hailstones,and their importance in cloud formation process and precipitation,as well as causing diseases in plants and animal kingdom,have been considered over two decades,but their significance in atmospheric processes are yet to be understood.A 1.3-D non-hydrostatic cumulus cloud model with bin-resolved microphysics is developed and is to used to examine the relative importance of sulfate aerosol concentrations on the evolution of cumulus cloud droplet spectra and ice multiplication process,as well as ice initiation process by ice nucleating bacteria in the growing stage and the key role of this process on the ice multiplication in the subsequent dissipating stage of cumulus clouds.In this paper,we will present some sensitivity test results of the evolution of cumulus cloud spectra,ice concentrations at various concentrations of sulfate aerosols,and at different ideal sounding profiles.We will discuss the implication of our results of ice nucleation processes.