The upper atmosphere and near-Earth space environment are in continuous interaction with the Earth’s magnetic field. In turn, the geomagnetic field is modified in shape and amplitude by the varying solar wind pressure and by electric current systems in the magnetosphere and ionosphere. Observing geomagnetic field variations at different time and spatial scales, therefore, has been of exceptionally high scientific value for investigations of the magnetosphere, ionosphere and thermosphere. Examples include the great progress in explaining different aspects in the auroral current system, and providing observational evidence of predicted low amplitude ionospheric currents in the nighttime low-latitude F-region ionosphere. Furthermore, continuous magnetic observations of the equatorial electrojet and the Sq-current system have recently advanced the investigation of atmospheric tides. We invite papers on the interpretation of magnetic field variations for the purpose of investigating the near-Earth space environment. Papers that combine magnetic field observations with measurements of other parameters are particularly encouraged. Discussions on recent scientific findings as well as review papers are welcomed. This session is organized in honor of Hermann Lühr. In addition to his initiation of regional ground-based magnetometer arrays, Dr. Lühr has significantly advanced this field of research through his leadership and realization of many highly accurate magnetic field satellite missions in low Earth orbit and his support to install regional variometer arrays.