Description:

The planetary boundary layer (PBL) is characterized by rapid changes in temperature, humidity, and wind speed, and is where we experiment the weather. Surface processes such as turbulence and friction affect the PBL, which in turn modulate convective development and momentum transport, thus affecting the coupling between the surface and the free troposphere. Hence, understanding the dynamics and physics of the PBL is critical for a range of applications, including weather, air quality, and climate. In this regard, novel instrumentation and novel methods of combining existing instruments have helped advance our understanding of the PBL processes. This session invites presentations that report on these latest advances, including but not limited to: advances in (1) in-situ measurements with balloons and aircraft, (2) remote sensing with radar, lidar and radiometers, (3) ground-based measurements with sonic anemometers and flux towers, and (4) the combination of multiple observation platforms. The session will cover a range of topics, including PBL height and variability, turbulent fluxes of heat, moisture, and momentum, and the interactions between the PBL and the free atmosphere. The aim is to promote a discussion on the challenges and opportunities in PBL measurements, such as the need for high-resolution measurements over heterogeneous terrain and the development of new measurement techniques for measuring vertical profiles of PBL properties.