Satellite limb measurements have become an essential tool to remotely sense the chemical composition of the Earth's atmosphere with a particular focus on the stratosphere. They enable combining near global sampling on a daily basis with vertical profiling capability and thus overcome some of the limitations of nadir or occultation measurements. Although the number of satellite limb instruments is currently declining, several missions are still operational (e.g., OSIRIS, SMR, ACE-FTS, MAESTRO, OMPS-LP and SAGE III) and several new missions are planned or will be launched in the near future (e.g., MATS, ICON, ALTIUS and several mini satellites). In addition, the data sets of several past limb sounders, particularly the Envisat instruments SCIAMACHY, MIPAS and GOMOS are still used for many scientific studies and new data products are developed based on measurements with these instruments.

This combined ACP/AMT special issue is open for submissions dealing with all aspects related to limb measurements (including limb scatter, limb emission and occultation) in the optical, IR and microwave spectral regions. This includes instrument development and characterization, retrieval algorithm development, validation studies, as well as scientific applications based on the retrieved data sets. We note that radio occultation measurements are outside the scope of the special issue.