Observations of High Altitude CO2 Hot Bands on Mars By the Orbiting Thermal Emission Spectrometer
Abstract
Using 12.5 cm-1 resolution MGS/TES limb observations from four Martian seasons (Ls=104-124, 170-190, 260-280 and 350-10), we have produced limb-geometry spectral averages from 40-120 km above the limb at 3 km resolution. Observations in the middle atmosphere (60-80 km) of Mars exhibit strong non-LTE IR emission in the 9.4 and 10.4 micron CO2 hot bands. The emission varies systematically with solar zenith angle and season. Recent improvements to the Kutepov non-LTE Mars model (1991,1998) have resulted in good agreement between theory and observation. For each season we observe a single continuous non-LTE emitting region extending over approximately 140 degrees of latitude. At both equinoxes, the emitting region is approximately centered on the equator. The height of the mean emission is approximately independent of latitude. On the other hand, at each solstice the emitting region is centered at a low latitude in its respective summer hemisphere. The mean heights of these emission regions increase with latitude toward their respective summer pole (N in northern summer, S in northern winter). We describe work in progress to further improve the model. Kutepov, A.A., D. Kunze, D.G. Hummer and G.B. Rybicky, J.Q.S.R.T. 46 (1991) 347-365; Kutepov, A.A., O.A. Gusev and V.P. Ogibalov, J.Q.S.R.T. 60 (1998) 199-220. This work was supported in part by NASA's Mars Data Analysis Program. NAS/NRC funding was provided by NASA's RRA Program.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #33
- Pub Date:
- November 2001
- Bibcode:
- 2001DPS....33.4404M