|
|||||
|
|
Water distribution in Martian permafrost regions from joint analysis of HEND (Mars Odyssey) and MOLA (Mars Global Surveyor) data |
|
| Authors: | N E Demidov W V Boynton D A Gilichinsky M T Zuber A S Kozyrev M L Litvak I G Mitrofanov A B Sanin R S Saunders D E Smith V I Tretyakov D Hamara |
| Institution: | 1. Institute of Physical-Chemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Russia 2. University of Arizona, Tucson, USA 3. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA 4. Space Research Institute, Russian Academy of Sciences, Profsoyuznaya ul. 84/32, Moscow, 117997, Russia 5. NASA Headquarters, Washington D.C., USA 6. NASA Goddard Space Flight Center, Greenbelt, Maryland, USA |
| Abstract: | We jointly analyze data from the High-Energy Neutron Detector (HEND) onboard the NASA Mars Odyssey spacecraft and data from the Mars Orbiter Laser Altimeter (MOLA) onboard the Mars Global Surveyor spacecraft. The former instrument measures the content of hydrogen (in the form of H2O or OH) in the subsurface layer of soil and the latter instrument measures the surface albedo with respect to the flux of solar energy. We have checked the presence of a correlation between these two data sets in various Martian latitude bands. A significant correlation has been found between these data at latitudes poleward of 40° in the northern hemisphere and at latitudes 40°–60° in the southern hemisphere. This correlation is interpreted as evidence for the presence of stable water ice in these regions under a dry layer of soil whose thickness is determined by the condition for equilibrium between the condensation of water from the atmosphere and its sublimation when heated by solar radiation. For these regions, we have derived an empirical relation between the flux of absorbed solar radiation and the thickness of the top dry layer. It allows the burial depth of the water ice table to be predicted with a sub-kilometer resolution based on near-infrared albedo measurements. We have found no correlation in the southern hemisphere at latitudes >60°, although neutron data also suggest that water ice is present in this region under a layer of dry soil. We conclude that the thickness of the dry layer in this region does not correspond to the equilibrium condition between the water ice table and the atmosphere. |
| Keywords: | Mars neutron spectroscopy albedo water ice |
| 本文献已被 SpringerLink 等数据库收录！ | |