A size-segregated stratospheric aerosol model with detailed polar stratospheric cloud (PSC) microphysics has been developed to study the formation and evolution of PSCs. For comparison with satellite and balloon-borne observations, one-dimensional simulations have been performed in Esrange/Kiruna (67.93¿N, 21.07¿E), Sweden during the period of winter 1996/1997. The modeled proportions of PSCs are consistent with the observations of volume, number, size distributions, and extinction coefficients derived from the in situ balloon-borne optical particle counter and the Improved Limb Atmospheric Spectrometer (ILAS) satellite sensor, demonstrating the capability of the model to capture PSC events. Model simulations successfully reproduce three major PSC events in the period from January to February 1997. The model is able to produce particle size distribution and number densities typical of the field observations in the Arctic stratosphere. Large HNO3-containing particles with a median radius of 6 ¿m and number densities in the range of 10-5 to 10-3 cm-3 are predicted to occur over a broad range of altitudes. Model simulations suggest that the homogeneous nucleation mechanism of type Ia PSCs out of type Ib PSCs plays a critical role in the formation of large HNO3-containing particles. The present model shows good potential for interpreting and validating the balloon-borne and satellite observations.