The interaction of processes between the land surface, the planetary boundary layer (PBL), and the free troposphere are crucial for the understanding of weather and climate including extremes such as heavy precipitation and droughts. This requires an advanced understanding and modeling of the exchange of momentum, water, energy, and carbon at interfaces. In this session, we present and discuss current research activities contributing to this understanding, including L-A interaction and feedback to the diurnal cycle of the PBL, clouds, and precipitation as well as surface fluxes such as evapotranspiration and entrainment. We accept observational and modeling approaches to address these challenges. With respect to the observations, emphasis is put on the application of new sensor synergies, e.g., using active remote sensing for studying land surface exchange processes and entrainment at the PBL top, which have been addressed in field campaigns. With respect to theoretical understanding and modeling, we are focusing on new insights by feedback diagrams and grey zone experiments down to the large eddy simulation scale.