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M. Sornig (I. Physikalisches Institut, Univ. zu Koeln), G. Sonnabend (NASA GSFC), D. Wirtz, R. Schieder (I. Physikalisches Institut, Univ. zu Koeln)
Recently Mars global circulation models have been developed from observational data acquired by the Mars Global Surveyor (MGS). To test these models of Mars atmospheric dynamics observations are needed. Mid-infrared-spectroscopy of CO2 offers a possibility to probe wind speeds in the Mars mesosphere around 80-100 km. Strong non-LTE emission in the upper atmosphere combined with absorption in the lower atmosphere allows direct measurements of relative wind speeds between those atmospheric regions.
The observed non-LTE features are very narrow (< 40MHz) and the line-shifts are in the order of only a few MHz therefore very high frequency resolution observations are required. Heterodyne spectroscopy offers such capabilities. The Cologne Tuneable Heterodyne Infrared Spectrometer (THIS) opens the mid-infrared wavelength from 7-28 micrometer to ultrahigh-resolution spectroscopy.
We present first measurements with THIS of CO2 absorption and non-LTE emission from the Martian atmosphere with a frequency resolution of 1MHz. Observations of the P(30) transition of CO2 at 9.6 micrometer were carried out during December 2003 with the 1.5 m McMath-Pierce solar telescope on Kitt Peak. Data analysis yields a wind speed of 74 m/s at 70 km for 15 degrees northern latitude. This result is in good agreement with model predictions of zonal winds in the mesosphere of Mars based on MGS data.
If you would like more information about this abstract, please follow the link to http://www.ph1.uni-koeln.de/workgroups/astro_instrumentation/this/. 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: sornig@ph1.uni-koeln.de
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.