The upper atmosphere carries weakly ionised plasma that is sensitive to influences from solar radiation and from interactions with the troposphere and stratosphere due to vertical coupling within the whole atmosphere. These signatures are visible in variations of electric currents flowing in the upper atmosphere. Electric currents have clear signatures in magnetic field observations both, on ground and in space. Therefore, geomagnetic observations reveal new insight into detecting effects from vertical atmospheric coupling monitored in the thermosphere.

One example is the detection of stratospheric warming events that are believed to create enhanced lunar tidal signatures, e.g., in the equatorial electrojet flowing at about 100 km altitude. These signatures, however, vary in longitude. We will present results from a study that investigates the effect of lunar tides and of stratospheric warming in the upper atmosphere based on magnetic data from ground and satellite observations.