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Detection of Mesospheric CO 2 Ice Clouds on Mars in Southern Summer
Author(s) -
Jiang F. Y.,
Yelle Roger V.,
Jain S. K.,
Cui J.,
Montmessin F.,
Schneider N. M.,
Deighan J.,
Gröller H.,
Verdier L.
Publication year - 2019
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 - 10.1029/2019gl082029
Subject(s) - mars exploration program , atmosphere of mars , occultation , atmospheric sciences , altitude (triangle) , longitude , atmosphere (unit) , aeronomy , mesopause , geology , physics , mesosphere , martian , astrobiology , astrophysics , astronomy , meteorology , stratosphere , latitude , geometry , mathematics
Abstract This paper reports the first detections of two high‐altitude nighttime CO 2 clouds on Mars during southern summer ( L s =264° and L s =330°) with stellar occultation measurements by the Imaging Ultraviolet Spectrograph on board the Mars Atmosphere and Volatile Evolution spacecraft. Interpretation of the transmission spectra with Mie theory indicates particle radii of ∼90–110 nm assuming a monodisperse distribution. The altitude profile of extinction indicates that the cloud layers are confined horizontally to sizes less than ∼500–700 km. Examination of the CO 2 density and temperature profiles reveals strong wave‐like perturbations. Supersaturated temperatures occur at the maximum negative extent of these wave‐like perturbations, which are organized in longitude with a dominant m =3 zonal harmonic. This suggests that tides are important in the formation of CO 2 clouds.