The refinement of our knowledge of spectroscopy and radiative transfer has become crucial to interpreting atmospheric observations across diverse planetary environments. Advances in high-resolution spectroscopy and molecular databases (e.g., HITRAN, ExoMol), together with new and legacy datasets from missions such as Cassini, Mars Express, Venus Express, ExoMars-TGO, Juno, and JWST, as well as upcoming missions like JUICE and ARIEL, have largely enhanced our ability to model energy transport, retrieve atmospheric composition of Solar System objects and exoplanets, and characterize complex chemistry, including that of aerosols and clouds.

These developments enable deeper insights into current atmospheric dynamics and long-term climate evolution. We invite contributions to a focus session on planetary atmospheres characterization across the Solar System and beyond, with atmospheric spectroscopy as conceptual cornerstone. Topics include but are not limited to: laboratory and remote sensing spectroscopic analysis, development and application of radiative transfer models, and interpretation of atmospheric processes through observations. We also encourage contributions on long-term evolution of atmospheres via comparative planetology and cross-disciplinary approaches. This session aims to strengthen and grow the planetary atmospheres community by fostering dialogue among researchers working in the mentioned topics. Theoretical, observational, and experimental contributions are invited.