This special issue aims to highlight advances in spectroscopic techniques for applications in atmospheric science. It will highlight cutting-edge measurements of atmospherically relevant species, including aerosol, isotopologues, and trace gases, using optical cavity-based techniques. Such techniques can include cavity-enhanced methods for sensitive absorption and extinction measurements as well as advances in frequency comb techniques. Techniques based on both broadband and laser sources from the ultraviolet to infrared will be considered. Papers based on both laboratory and field measurements are welcome.