When solar storms force the earth's auroras to lower latitudes, winds in the thermosphere reverse direction and are whipped up to velocities of 2250 km/h. A computer model has now been developed that will describe the circulation of the thermosphere—a 400-km blanket enveloping the earth, with its bottom boundary at an altitude of 80 km—and its interaction with the auroras.
Raymond G. Roble, of the National Center for Atmospheric Research, explained at the AGU Fall Meeting that the thermospheric model might be useful to predict variations in storm time and atmospheric drag on some earth satellites. If the thermosphere's dynamics are better understood, he reasoned, more accurate predictions of a satellite's orbital decay can be made. The model may also help to predict the effects of communications equipment and magnetic forces on power grids.