Modeling of Martian seasonal caps from HEND/ODYSSEY data

M.L. Litvaka, I.G. Mitrofanova, A.S. Kozyreva, A.B. Sanina, V.I. Tretyakova, W.V. Boyntonb, D. Hamarab, C. Shinoharab, R.S. Saundersc

aSpace Research Institute, Laboratory of Gamma Ray Spectroscopy, Profsojuznaya Street 84/32, Moscow 117997, Russia
bUniversity of Arizona, Lunar and Planetary Laboratory, Tucson AZ 85721, USA
cNASA HQ, Washington, DC 20514, USA

Abstract - In this paper, we have analyzed neutron spectroscopy data gathered by the high energy neutron detector instrument onboard Mars Odyssey in order to study the behavior of CO2 condensed mass at the polar regions of Mars. It is known that observation of the neutron albedo of Mars provides not only information on distribution of water ice/bounded water through Martian subsurface but is also sensitive to the condensation/sublimation of atmospheric CO2 at the Martian poles. Analysis of temporal variations of neutron flux between summer and winter seasons allowed the creation of multidimensional model of CO2 deposition describing behavior of CO2 condensed mass as a function of longitude, latitude and time. Based on this model, we have estimated the total masses of north seasonal cap ((3.8 ± 0.4) × 1015 kg), south seasonal cap ((6.3 ± 0.6) × 1015 kg) and compared our estimations with predictions of General Circulation Model. Furthermore, using the data gathered during second Martian year on the orbit, we have conducted preliminary comparison between seasonal cycles of two successive Martian years.
DOI: 10.1016/j.asr.2005.09.007 -