Water ice clouds over the Martian tropics during northern summer

• Published in: Geophysical research letters Vol. 37; no. 18
• Main Authors: Heavens, N. G., Benson, J. L., Kass, D. M., Kleinböhl, A., Abdou, W. A., McCleese, D. J., Richardson, M. I., Schofield, J. T., Shirley, J. H., Wolkenberg, P. M.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.09.2010; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Altitude; Atmospheric circulation; Atmospheric sciences; Chemistry; Clouds; Earth sciences; Earth, ocean, space; Exact sciences and technology; General circulation models; Ice; Mars; observations; Physics; Planetology; Planets; Radiation; Summer; Tropical environments; tropics; polar regions; South Pole; Antarctica; atmosphere; altitude; Atmosphere model; Heating rate; tropical zone; Summer; climate; Meridional circulation; Ice cloud; intensity; Mars; warming; Mixing ratio; MRO space probe
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2010GL044610

Atmospheric models suggest that infrared heating due to water ice clouds over the tropics of Mars during early northern summer has a significant impact on the thermal structure of the tropics at cloud level and of the middle atmosphere near the south pole. Retrievals from limb observations by the Mars Climate Sounder on Mars Reconnaissance Orbiter during early northern summer show that water ice clouds over the northern tropics are thinner and higher than in published model results. Later in this season, the latitudinal extent, apparent mass mixing ratio (and infrared heating rate), and altitude of nighttime tropical clouds significantly increase, reaching a maximum just before northern fall equinox. Published model results do not show this transition. By underestimating the altitude at which water ice clouds form, models also may underestimate the intensity of the meridional circulation at higher altitudes in the tropics during northern summer.