Convective instability in the martian middle atmosphere

• Published in: Icarus (New York, N.Y. 1962) Vol. 208; no. 2; pp. 574 - 589
• Main Authors: Heavens, N.G., Richardson, M.I., Lawson, W.G., Lee, C., McCleese, D.J., Kass, D.M., Kleinböhl, A., Schofield, J.T., Abdou, W.A., Shirley, J.H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.08.2010; Elsevier
• Subjects: Astronomy; Atmospheres, Dynamics; Atmospheres, Structure; Atmospherics; Circulation; Earth, ocean, space; Exact sciences and technology; Gravity waves; Instability; Mars; Mars, Atmosphere; Meteorology; Middle atmosphere; Retrieval; Solar system; Stability; Winter; Atmospheres, Structure; Atmospheres, Dynamics; Mars, Atmosphere; Meteorology; Convective instabilities; Atmospheres; Northern hemisphere; Saturation; Atmospheric instability; Mars; Atmospheric temperature; Dust storm; Dynamics; Atmosphere; Models; Modelling; Solar system; Structure; Gravity waves
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2010.03.023

Dry convective instabilities in Mars’s middle atmosphere are detected and mapped using temperature retrievals from Mars Climate Sounder observations spanning 1.5 martian years. The instabilities are moderately frequent in the winter extratropics. The frequency and strength of middle atmospheric convective instability in the northern extratropics is significantly higher in MY 28 than in MY 29. This may have coupled with changes to the northern hemisphere mid-latitude and tropical middle atmospheric temperatures and contributed to the development of the 2007 global dust storm. We interpret these instabilities to be the result of gravity waves saturating within regions of low stability created by the thermal tides. Gravity wave saturation in the winter extratropics has been proposed to provide the momentum lacking in general circulation models to produce the strong dynamically-maintained temperature maximum at 1–2 Pa over the winter pole, so these observations could be a partial control on modeling experiments.