Title: Rotational Speed of the Upper Atmosphere : an Increase with Height above 200 km
Abstract: THE average speed of rotation of the upper atmosphere can be determined by analysing small changes in the inclinations of satellite orbits to the equator. Previous studies1,2 have indicated that, on average, the upper atmosphere at heights of 200–300 km is rotating faster than the Earth: the mean value obtained for the ratio Λ of the rotational speed of the atmosphere to that of the Earth was Λ = 1.27, which corresponds to a mean west-to-east wind speed of 100 m/s in middle latitudes. These previous studies, however, were not accurate enough to allow any definite conclusions to be drawn about the variations of Λ with height, time or latitude.