CO2 Snow Depth and Subsurface Water-Ice Abundance in the Northern Hemisphere of Mars
I. G. Mitrofanov,1*
M. T. Zuber,2
M. L. Litvak,1
W. V. Boynton,3
D. E. Smith,4
D. Drake,5
D. Hamara,3
A. S. Kozyrev,1
A. B. Sanin,1
C. Shinohara,3
R. S. Saunders,6
V. Tretyakov1
Observations of seasonal variations of neutron flux from the high-energy neutron detector (HEND) on Mars Odyssey combined with direct measurements of the thickness of condensed carbon dioxide by the Mars Orbiter Laser Altimeter (MOLA) on Mars Global Surveyor show a latitudinal dependence of northern winter deposition of carbon dioxide. The observations are also consistent with a shallow substrate consisting of a layer with water ice overlain by a layer of drier soil. The lower ice-rich layer contains between 50 and 75 weight % water, indicating that the shallow subsurface at northern polar latitudes on Mars is even more water rich than that in the south.
1 Space Research Institute, Russian Academy of Sciences, Moscow, 117997, Russia.
2 Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139–4307, USA.
3 Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
4 Laboratory for Terrestrial Physics, NASA–Goddard Space Flight Center, Greenbelt, MD 20771, USA.
5 Tech-Source, Santa Fe, NM 87505, USA.
6 NASA Headquarters, Washington, DC 20514, USA.
* To whom correspondence should be addressed. E-mail: imitrofa{at}space.ru
