FOR 5639:  Land-Atmosphere Feedback Initiative (LAFI)

• Subject Area: Geosciences
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 514721519

The quality of weather forecasts, seasonal simulations, and climate projections depends critically on the adequate representation of land-atmosphere (L-A) feedbacks. These feedbacks are the result of a highly complex network of processes and variables related to the exchange of momentum, energy, and mass. Significant challenges persist in understanding processes and feedbacks, which this initiative will address.The Land-Atmosphere Feedback Initiative (LAFI) is an interdisciplinary consortium of researchers from atmospheric, agricultural, and soil sciences as well as from bio-geo-physics, hydrology, and neuroinformatics proposing a novel combination of advanced research methods. The overarching goal of LAFI is to understand and quantify L-A feedbacks via unique synergistic observa-tions and model simulations from the micro-gamma (approx. 2 m) to the meso-gamma (approx. 2 km) scales across diurnal to seasonal time scales. LAFI consists of a network of closely intertwined projects addressing six research challenges formulated as objectives and hypotheses on 1) alternative similarity theories, 2) the impact of land-surface heterogeneity, 3) partitioning evapotranspiration, 4) understanding entrainment, 5) synergistic characterization of L-A feedback, and 6) droughts or heatwaves potentially investigated by ad-hoc field observations. Collaboration across the twelve projects will be fostered by three Cross Cutting Working Groups on Deep Learning, Sensor Synergy and Upscaling, as well as the LAFI Multi-model Experiment. Our research highlights include: A) The observation of L-A system processes and feedbacks at two sites dominated by agricultural land use: I) The Land-Atmosphere Feedback Observatory (LAFO) at the University of Hohenheim enhanced by a worldwide-unparalleled synergy of instruments, e.g., combining for the first time measurements of water stable isotopes, fiber-optic distributed temperature sensors, and scanning lidar systems, II) the Meteorological Observatory Lindenberg-Richard Aßmann Observatory (MOL-RAO) of the German Meteorological Service providing a long-term data set for studying the statistics of droughts and heatwaves. B) Under-studied and poorly understood processes in the L-A system, C) Improvement and application of L-A system models down to the large eddy scales with advanced representation of vegetation and water stable isotopes. D) Application of deep learning (DL) methods for identifying key and potentially novel factors in process descriptions. Based on this combination of research components, we will characterize the multi-dimensional phase space of L-A system variables with various process-based metrics over an entire vegetation period in order to reach the overarching LAFI goal. Fueled by the tightly interwoven collaborative research, the LAFI research unit will gain crucial new insights into L-A feedbacks and processes for the characterization of coupling strengths over agricultural regions in central Europe.

• DFG Programme: Research Units
• International Connection: Belgium, Luxembourg

Projects

• Coordination Funds (Applicant Wulfmeyer, Volker )
• Effect of land-atmosphere coupling on vegetation behaviour (Applicant Schymanski, Stanislaus Josef )
• Impact of terrestrial hydrology on L-A feedbacks and isotope signatures (Applicant Kunstmann, Harald )
• Investigating the impact of land surface heterogeneity on near- surface circulations and fluxes (Applicant Thomas, Christoph )
• Investigations of ABL dynamics and structure over heterogeneous surfaces with turbulence-resolving simulations (LES) (Applicant Mauder, Matthias )
• Machine Learning for improved understanding of L-A processes and feedbacks (Applicants Butz, Martin ;  Wulfmeyer, Volker )
• Observation and investigation of the land-atmosphere system, atmospheric boundary layer processes, and fluxes (Applicants Beyrich, Frank ;  Jagdhuber, Thomas ;  Kübert, Angelika ;  Mauder, Matthias ;  Orlowski, Natalie ;  Rajtschan, Verena ;  Streck, Thilo ;  Thomas, Christoph ;  Wulfmeyer, Volker )
• Remote sensing of vegetation canopy properties: States & spatio-temporal dynamics (Applicant Jagdhuber, Thomas )
• Scale dependent impact of dynamic vegetation heterogeneity on heat and moisture fluxes at the blending height (Applicant Warrach-Sagi, Kirsten )
• Scale interaction in Land-Atmosphere (L-A) feedback (Applicant Pongratz, Julia )
• Using real-time isotopic in-situ measurements to partition evapotranspiration into soil evaporation and plant transpiration at two distinct cropland sites (Applicants Kübert, Angelika ;  Orlowski, Natalie )

• Spokesperson: Professor Dr. Volker Wulfmeyer