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First Evidence of Persistent Nighttime Temperature Structures in the Neutral Thermosphere of Mars
Author(s) -
Pilinski M.,
Bougher S.,
Greer K.,
Thiemann E.,
Andersson L.,
Benna M.,
Elrod M.
Publication year - 2018
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 - 10.1029/2018gl078761
Subject(s) - thermosphere , atmosphere of mars , mars exploration program , dusk , atmospheric sciences , atmosphere (unit) , local time , martian , terminator (solar) , astrobiology , atmospheric escape , physics , amplitude , atmospheric temperature , environmental science , geophysics , astronomy , ionosphere , meteorology , quantum mechanics , statistics , mathematics
Abstract Using two Mars years of data collected by the Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatiles EvolutioN spacecraft, we reconstruct the local solar time structure of the Martian equatorial thermosphere for the dawn and dusk sectors. The results indicate the presence of several persistent features near the dusk and dawn terminators appearing in the neutral temperature and in the O, Ar, N 2 , and CO 2 densities. The dusk temperature features include a minimum at the terminator surrounded by two local maxima with amplitudes between 20 and 40 K. A nighttime temperature enhancement occurs at a local solar time of 4–5 hr and has an amplitude between 50 and 100 K relative to the surrounding temperatures. The observed enhancements are interpreted to be a result of either nighttime dynamical heating caused by converging and downwelling winds or of a terminator wave originating in the lower atmosphere.