The DOE SC program in Biological and Environmental Research (BER) hereby announces its interest in receiving applications for collaborative research in the Southeast U.S. Starting in the fall of 2024, the third Atmospheric Radiation Measurement (ARM) Mobile Facility in Bankhead National Forest in Alabama will initiate full operations to provide observations to improve process understanding and model representations of aerosol, cloud, and land-atmosphere interactions, together with key cross-coupling of those areas to quantify land-atmosphere feedbacks and aerosol-cloud interactions. This FOA will consider applications that address science challenges that are within scope of the Atmospheric System Research (ASR), Earth and Environmental System Modeling (EESM), and Environmental System Science (ESS) sub programs. Specifically, this FOA focuses on measurements, experiments, field data, modeling, analysis, and synthesis to provide improved understanding and representation of ecosystems, watersheds, atmospheric processes, and regional modeling in ways that advance the sophistication and capabilities of models that span from individual processes to Earth-system scales. This FOA will encompass four topics 1) vegetation and land-atmosphere interactions; 2) spatial heterogeneity and scaling; 3) convection, clouds, precipitation, and biogenic aerosols; and 4) extreme events and disturbance. Proposed research may integrate more than one topic. The inclusion of underrepresented, minority serving or emerging research institutions as part of research teams is encouraged.