How clouds and aerosols interact with atmospheric radiation depends on their macro and microphysical properties, which are crucial for understanding their impacts on weather, climate, and air quality. The picture is complicated by the fact that aerosols serve as condensation nuclei for water droplets and ice crystals, and hence affect the cloud life-time, brightness, and precipitation efficiency in non-linear ways. Recent advances in polarimetric remote sensing and in situ instruments provide valuable information on the size, shape, composition, and optical properties of these particles at unprecedented temporal and spatial scales. On top of that, multiple US and international missions are planned in the coming years for detailed polarimetric measurements from space. These advances contribute to broaden our understanding of the complex interactions between aerosols, clouds, and radiation. This session invites presentations that report on the latest advances on passive and active polarimetric measurements from satellites, airplanes, or ground-based instruments. These include but are not limited to: (1) development of new instruments and concepts; (2) reports from past and future field-campaigns; (3) new retrieval techniques and algorithms, including combination of polarimetric and other types of measurements; and (4) studies of clouds, aerosols or their interactions though these new and rich polarimetric approaches.

