This project is elucidating the role of black carbon aerosols in the climate system by studying the impact of absorbing aerosols on tropical convection and precipitation. We utilize space-based remote sensing integrated with ground networks and field campaign data, and observationally-based 3D aerosol-climate model simulations, to investigate the local and remote effects of black carbon aerosols on clouds, precipitation and the hydrologic cycle in the tropics. The objective is to quantify the magnitude of the climatological impact of black carbon aerosols, and to identify the dominant dynamic and physical mechanisms that govern this impact. We use MODIS satellite and AERONET surface measurement data to derive the global and climatological distributions of optical and radiative properties of aerosols; MODIS, CERES and TRMM cloud and precipitation data combined with the aerosol climatological data to derive empirical regional relationships between the aerosol concentration and optical properties, cloud properties, and precipitation rates; and aerosol climatological data to constrain an aerosol-climate model to perform observationally-based climate-scale integrations and sensitivity simulations.