Atmospheric tide

As tidal wind is a fast, equatorial wind in the thermosphere is called, caused by solar radiation pressure induced Distinguished. The name of this wind goes back to his 24 -hour periodicity.

Due to the diurnal solar radiation is formed in equatorial latitudes, a high pressure zone, the maximum is reached in the afternoon. This zone is called because of their shape as pressure bump ( engl. pressure bulge ). Twelve hours offset this, there is a corresponding low pressure zone, the pressure minimum is, however, less sharply defined than the pressure maximum.

Between these two zone, a pressure differential of about 4 uPA, which is sufficient to allow a balance wind flow which reaches a speed of up to 200 m / s (~ 700 km / h ). This is the day directed westward.

A consequence of the so-called tidal wind fountain effect which influences the equatorial ionosphere.