The dynamical behaviour of the upper thermosphere in the southern polar region has been investigated for a range of solar and geomagnetic activity and as a function of season, using a series of simulations by a coupled thermosphere - ionosphere model. The predicted behaviour in the southern winter period can be compared with recent ground-based Fabry-Perot interferometer observations of the OI 1 D emission from the Amundsen-Scott station at the South Pole.