The midlatitude thermospheric dynamics from an interhemispheric perspective

We also use the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) to simulate the seasonal changes of winds and the effects from Sub-Auroral Polarization Streams.

The observations and TIEGCM simulations show a clear seasonal variation with more westward and equatorward summer winds. The TIEGCM runs overestimate the westward zonal winds and underestimate the electron densities in the northern summer. We believe that the underestimated TIEGCM electron density leads to a weak ion drag effect in the model, and strong westward zonal winds.