Monitoring of aerosol forcing of climate from space: analysis of measurement requirements

We discuss the rationale for long-term monitoring of the global distribution of natural and anthropogenic aerosols (black carbon, sulfates, mineral aerosols, etc.) and clouds with specificity, accuracy, and coverage sufficient for a reliable quantification of the direct and indirect aerosol effects on climate, the anthropogenic component of these effects, and the long-term change of these effects caused by natural and anthropogenic factors. This discussion is followed by the formulation of specific scientific objectives of the Aerosol Polarimetry Sensor component of the National Aeronautics and Space Administration's Glory Project established within the framework of the US Climate Change Research Initiative.