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Role of stationary and transient waves in CO 2 supersaturation during northern winter in the Martian atmosphere revealed by MGS radio occultation measurements
Author(s) -
Noguchi K.,
Morii Y.,
Oda N.,
Kuroda T.,
Tellmann S.,
Pätzold M.
Publication year - 2017
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2016je005142
Subject(s) - supersaturation , martian , atmosphere of mars , atmospheric sciences , atmosphere (unit) , atmospheric wave , saturation (graph theory) , mars exploration program , gravity wave , chemistry , environmental science , geology , meteorology , physics , gravitational wave , astrobiology , astrophysics , mathematics , combinatorics , organic chemistry
The Martian atmosphere, which mainly consists of carbon dioxide (CO 2 ), is characterized by extremely low temperatures that cause CO 2 gas to freeze and dry ice to form. To date, temperatures below the CO 2 saturation temperature, which can be attributed to the effects of atmospheric waves, have been observed in the polar winter and in the mesosphere. Using data from Mars Global Surveyor (MGS) radio occultation measurements, we investigated the role of large‐scale atmospheric waves including stationary and transient waves at northern high latitudes in winter on CO 2 supersaturation. A distinct longitudinal dependence of CO 2 supersaturation was observed at altitudes higher than the pressure level of 200–400 Pa, where a stationary wave with a wave number of 2, whose temperature amplitude had minima at 30–100 Pa, lowered the background temperature to a level close to the CO 2 saturation temperature. However, the stationary wave alone was not sufficient to cause CO 2 supersaturation. Additional temperature disturbances caused by transient waves, namely, superposition of both waves, had a significant role in CO 2 supersaturation. The longitudinal dependence of the occurrence of CO 2 supersaturation revealed by our study might affect the longitudinal distribution of CO 2 snowfall and the formation of the seasonal polar ice cap.