North-south asymmetry of Eolian features in martian polar regions: analysis based on crater-related wind markers |
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| Authors: | P Thomas |
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| Institution: | Laboratory for Planetary Studies, Cornell University, Ithaca, New York 14853, USA |
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| Abstract: | A comparison of crater-related wind markers in the north and south polar (40–90° latitude) regions of Mars has been made on the basis of comprehensive mapping from Viking Orbiter and Mariner 9 Images. Wind streaks show that present wind activity is most effective in both north and south in the southern spring and summer. This asymmetry is consistent with the present asymmetry of climate. The more massive intracrater dune fields are also oriented with the presently strongest winds. This alignment may reflect a long-term asymmetry in the effectiveness of northern and southern spring flow because reorientation times far exceed the period of cycles of hemispherical climate asymmetry, ≈51, 000 years. Streaks originating from dark crater splotches indicate that windflow away from the south pole is effective over a larger latitude range than it is in the north. This difference may be partly responsible for the contrasting distribution of dune sand in the north and south polar regions. |
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