The dissipation of solar wind energy in the upper atmosphere generates a disturbance whose morphology depends on local time, season, and magnetic activity. A statistical analysis of esro 4 data reveals that (1) in the afternoon/evening sector the disturbance boundary coincides with the region of electric current dissipation along the auroral oval; (2) in the midnight/early morning sector, dynamical effects extend the disturbance zone to lower latitudes, and this expansion is strongly dependent on season and magnetic activity; and (3) in the late morning sector, direct heating effects along the auroral oval are superimposed on the residuals of the early morning disturbance. These results are consistent with previous observations and provides new boundary conditions for upper atmospheric models.