In recent years, the Research Centre Jülich and the Karlsruhe Institute for Technology (KIT) have developed the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) for operation on the new German research aircraft HALO (High Altitude and LOng Range Research Aircraft) and the Russian M55-Geophysica. GLORIA utilizes the newly developed limb-imaging technique that provides 3-D observations of multiple trace gases, aerosols, and clouds in the UTLS with unprecedented resolution. The instrument will participate in numerous scientific aircraft campaigns addressing upper troposphere–lower stratosphere (UTLS) science. The first large HALO campaign was TACTS (Transport and composition in the UT/LMS), which took place in summer 2012. Several HALO campaigns will follow and GEOPHYSICA campaigns will be proposed at EU level.

The special issue on GLORIA will introduce the limb-imaging technique that has been jointly developed at Jülich and Karlsruhe. GLORIA is the first instrument that uses this technique, and further application on balloons and satellites (PREMIER, one of three candidates for ESA's 7th Earth Explorer mission) is envisaged.

The special issue shall also provide a reference for future scientific publications using GLORIA observations. It includes all technical aspects of the instrument, a detailed description of the algorithms used, and studies on the real performance during test flights onboard GEOPHYSICA (~21km ceiling height) that were made during the ESSENCE campaign in Kiruna in December 2011.