Precise simulation of climate depends upon the accuracy of the parameterised physical processes and model configuration.  Global Climate model (GCM) spatial resolution is sufficient to properly simulate large-scale evolution of the atmosphere. However, studies on sensitivity of horizontal resolution in GCMs show a decrease of systematic errors and an increase of spatial and temporal variability with increase in resolution. Physical processes related to topography, such as precipitation also improve with higher resolution. The horizontal resolution, the domain size and area are among the parameters related to the model configuration that can alter the regional climate model (RCM) solution (Giorgi and Mearns, 1999).

Aerosols have a relatively short lifetime and their concentration over a given area is the end result of the atmospheric circulation, cloud cover, cloud microphysical properties and precipitation. Ghan et al. (2001) have found that the indirect radiative effect of anthropogenic aerosols is particularly sensitive to GCM horizontal grid resolution. Even though sensitivity of horizontal resolution on different RCMs have been carried out, very little is known on its impact on high resolution RCMs coupled with advanced aerosol dynamics and chemistry.  In this work, such a study is carried out for the period June 2003. The ability of the model to develop smaller-scale features and its impact on clouds, precipitation, large-scale atmospheric circulation and aerosol transport and emissions is investigated. Horizontal resolutions of approximately 25 km (0.25°), 50 km (0.5°) and 100 km (1.0°) is used for the numerical experiment with the regional climate model REMOTE for the European domain as shown in Figure 1.