The geomagnetic variation in the upper atmosphere

A brief review is given of the development of models of the geomagnetic variation in the thermosphere and exosphere, including some recent models based mainly on satellite-borne gas analyzer measurements. One recent model, derived from ESRO4 data, is described in detail and compared with the model in CIRA72. The limitations of this model are discussed. The model in the MSIS comprehensive model is also examined briefly. There appears to be a serious error in the amplitude of the exospheric temperature increase predicted by the MSIS model.