Despite substantial progress in the last decades, the climate impact of anthropogenic aerosols is still highly uncertain, especially at regional scale. One key area were improvements are much needed is the understanding of the physical pathways linking aerosol emissions-radiative forcing-climate variations, both regionally and remotely, via, for example, atmospheric circulation changes. This session welcomes contributions from observations and modelling studies that contribute to advancing the understanding of the mechanisms for the aerosol impact on regional climate worldwide, from the Tropics to high latitude regions, and its interactions with other climate forcing factors and natural variability. Studies focusing on aerosol-induced changes in variability, long-term trends, and extremes in the hydrological cycle, in the recent past as well as the coming decades, are particularly solicited.