DPS 2001 meeting, November 2001
Session 19. Mars Atmosphere Posters
Displayed, 9:00am Tuesday - 3:00pm Saturday, Highlighted, Wednesday, November 28, 2001, 10:30am-12:30pm, French Market Exhibit Hall

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[19.24] A Martian Year of Mapping by the MGS Horizon Science Experiment

T.Z. Martin (JPL), J.R. Murphy (NMSU)

Thermal mapping of the Mars atmosphere at 15 micrometers for more than a Martian year reveals a wealth of phenomena, both persistent and transitory, that give us a stronger understanding of the effects of dust and seasonal and interannual change. Equatorial thermal lows persist most of the year near west longitudes 100 and 300\circ. A transition occurred near Ls 220\circ in 1999 between an equatorially warm state to a warmer condition with maxima in both northern and southern middle latitudes. This bifurcation, probably related to the Hadley circulation, was absent during the early 2001 storm period. Between Ls 260-285\circ in 1999, maximum temperatures occurred at the south pole. The planet-encircling dust storm of 2001 displays dramatic thermal behavior highly reminiscent of that seen during the Viking 1977 dust storm season. The 2001 event commenced near Ls 185\circ, early in the dust storm season. Strong waves appear in the northern subpolar latitudes, also similar to 1977.

Differences between the first and second years during northern summer are subtle in nature. Diurnal coverage of the atmosphere at six times of day shows significant differences in the dust storm seasons of 1999 and 2001. Maxima in the south occur late in the afternoon both years. In 1999 the northern peak occurred in late morning, but the stronger 2001 event showed afternoon peaks. Both storm seasons heated the southern polar latitudes effectively, but neither was able to warm the north pole, perhaps due to the strong vortex winds associated with the existing latitudinal temperature gradient. Amplitudes and phases of stationary and tidal wave modes have been extracted by J. Murphy using software developed by D. Banfield for use with TES data.

The MGS spacecraft was tilted by 16\circ in August 2001 for propellant conservation; this change has only a minor effect on operation of the MHSA for science, enabling continued use until perhaps 2003.

This research was funded by the Mars Data Analysis Program and carried out by the Jet Propulsion Laboratory, California Institute of Technology.

If you would like more information about this abstract, please follow the link to http://mars.jpl.nasa.gov/mgs/sci/horse/index.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: Terry.Z.Martin@jpl.nasa.gov

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