Variation in the eddy diffusion coefficient near the turbopause affects not only the composition but also the wind and temperature fields of the thermosphere. Composition and wind fields are strongly coupled such that for long term (annual) variations the eddy diffusion effects are entirely different in one and three dimensional models. Hoizontal winds, driven by the oxygen bulge which in turn is induced by eddy diffusion, act as a feedback to significantly reduce the composition variations in geeral and the ratio between He and O amplitudes in particular. The resulting He amplitude from three dimensional calculations is by about a factor of ten lower than the O amplitude above 150 km, in striking contrast to composition data. Due to temperature variations, isopycnic levels develope at 250 km (He) and 450 km (O), such that at higher altitudes both species vary in phase with the eddy diffusion coefficient. The eddy diffusion mechanism must thus be excluded as a principle candidate for describing the spherical asymmetries in the annual variation of the thermosphere. The temperature increase associated with adiabatic heating from the wind component can be substantial; turbulent energy is thereby effectively transported from the mesosphere up into the thermosphere.