The meteorological equator in the stratosphere and mesosphere

Fluctuations and periodic oscillations of the thermodynamic properties of the atmosphere between 25 and 80 km are analyzed in this paper to better define the structure of the tropical atmosphere. The nature of temperature and density variations at locations between 22 degrees N and 8 degrees S is examined by means of harmonic analysis. Amplitudes and phases of the annual and semiannual components of the temperature and density cycles indicate that the meteorological equator within the stratosphere and lower mesosphere lies south of Ascension Island. The paper is only one part of a larger investigation aimed at providing a set of mean monthly atmospheric models from the surface to 90 km at 15 degrees latitude intervals between equator and pole.