The planetary boundary layer (PBL) has become a major focus of Earth atmospheric and climate science in recent years. It is central to the interchange of heat and moisture between the Earth’s surface and the free troposphere, the turbulent transport of aerosol and chemical pollutants, radio wave propagation, and near- and long-term climate prediction, in addition to equilibrium climate sensitivity. The PBL remains exceedingly difficult to measure from space: space-based lidar, microwave and hyperspectral infrared nadir radiance sounding, and GNSS radio occultation, for example, all offer unique advantages in measuring the PBL but with their own unique complications. In this session, we encourage presentations on recent advances in modeling the PBL, in observing the PBL, and in concepts to observe the PBL from space. The idea is to provide a forum for modelers, data analysts and mission architects to engage in an in-depth conversation on linking theory and observation.