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Evidence of an extra‐terrestrial source for the mesospheric sodium layer
Author(s) -
Clemesha B. R.,
Kirchhoff V. W. J. H.,
Simonich D. M.,
Takahashi H.
Publication year - 1978
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl005i010p00873
Subject(s) - mesosphere , lidar , atmospheric sciences , sodium , layer (electronics) , geology , scale height , atmosphere (unit) , surface layer , constant (computer programming) , geophysics , environmental science , meteorology , physics , materials science , remote sensing , stratosphere , computer science , metallurgy , composite material , programming language
Lidar observations of the mesospheric sodium layer, made at São José dos Campos (23°S, 46°W), show three distinct types of organized structure in the vertical distribution of sodium. Profiles averaged over several days show a smooth but asymmetrical distribution. A sequence of profiles for a given night normally shows a wavelike structure which descends through the layer with time. Very occasionally an extremely narrow peak is observed at a constant height for several hours. On one occasion a layer 2.5 km wide, with scale heights of 700 m on the bottomside and 900 m on the topside, was observed to persist at a constant height for three hours. It is concluded that such a layer could neither be produced by neutral density perturbations nor by photochemical processes and therefore indicates a source of sodium in the mesosphere.