To showcase their strong thematic connection, the two sessions “Air-Land Interactions (General Session)” and “Understanding and Characterization of Land-Atmosphere Feedback” were merged.

The session is addressed to experimentalists and modellers working on land surface fluxes from local to regional scales. The programme is open to a wide range of new studies in micrometeorology. The topics include the development of new devices, measurement techniques and experimental design methods, as well as novel findings on surface layer theory and parametrization at the local scale. The theoretical parts encompass soil-vegetation-atmosphere transport, internal boundary-layer theories and flux footprint analyses, etc.. Of special interest are comparisons of experimental data, parametrizations and models. This includes energy and trace gas fluxes (inert and reactive) as well as water, carbon dioxide and other GHG fluxes. Specific focus is given to outstanding problems in land surface boundary layer descriptions such as complex terrain, energy balance closure, stable stratification and night time fluxes, as well as to the dynamic interactions with atmosphere, plants (in canopy and above canopy) and soils including the scale problems in atmosphere and soil exchange processes.

The understanding of feedback processes in the land-atmosphere (L-A) system is crucial for advanced modeling and prediction of weather and climate. However, the impact of soil moisture and evapotranspiration on the diurnal cycle of the planetary boundary layer (PBL), clouds, and precipitation remains a sore gap in our understanding of weather processes and climate statistics. For this purpose, the exchange of momentum, water, energy, and carbon at the land surface and at the top of the PBL has to be investigated from the local to regional scales in great detail. In this session, 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 for studying L-A exchange processes and entrainment at the PBL top based on long-term data sets or recent field campaigns, e.g., combining multi-tower, scanning lidar, airborne, and satellite observations. With respect to theoretical understanding and modeling, we welcome the study of feedback processes as well as the derivation and application of feedback metrics from the mesoscale to turbulent scales, e.g., derived by large eddy simulations.