Open AccessA nighttime temperature maximum in the thermosphere above Saint Santin in winter
Author(s) -
Oliver W. L.,
Martinis C. R.,
Hickey D. A.,
Wright A. D.,
AmoryMazaudier C.
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012ja017855
Subject(s) - incoherent scatter , thermosphere , solstice , middle latitudes , ionosphere , atmospheric sciences , amplitude , physics , environmental science , latitude , climatology , geology , optics , astronomy
The Saint Santin (45°N) incoherent scatter radar data base shows a local enhancement in nighttime ion temperature that occurs in winter only. Its amplitude can exceed 100 K and averages 40 K on the basis of a conservative computation. The enhancement peaks near 4 LT and has a duration of about 4 hours. We discuss two possible explanations for this feature: (1) it is caused by the convergence of global winds at the global pressure minimum, under which Saint Santin rotates at winter solstice, and (2) it is an extension or propagation of the well‐known low‐latitude midnight temperature maximum to midlatitudes, perhaps to that pressure minimum.