MARS: The North Polar Sand Sea and related wind patterns

Viking Orbiter 2 images of the north polar region reveal an enormous sand sea (erg) covering an area of >5×105 km2 around the perennial ice cap. All dunes are either transverse or barchan. The various dune morphologies and modification of primary dune types reflect a wind regime having more than one wind direction. In the summer, two major wind directions prevail: (1) off-pole winds that become easterly due to coriolis forces and (2) on-pole winds that become westerly. During the winter and/or spring, only the on-pole winds exist. Strong winds (>75 m/s) are required for sand accumulation to form the thick transverse dunes. The strongest winds in the north polar region are thought to exist during summer over the transverse dune field between 110°W and 220°W; this area is a relatively warm belt (temperature >230 K) between two ice zones (temperature <220 K). A frequent cyclogenetic process in this area may cause sand storms. The dunes seem to be currently active. The lack of well-developed longitudinal dunes implies that the dune field is young. The relationship of the present dune field to the perennial ice indicates that the dunes began to form after the formation of the present ice cap.

[1]  H. T. Smith.  PHYSICAL EFFECTS OF PLEISTOCENE CLIMATIC CHANGES IN NONGLACIATED AREAS: EOLIAN PHENOMENA, FROST ACTION, AND STREAM TERRACING , 1949 .

[2]  F. Simons.  A Note on Pur-Pur Dune, Virú Valley, Peru , 1956, The Journal of geology.

[3]  S. Burk.  Diurnal Winds Near the Martian Polar Caps , 1976 .

[4]  F. Palluconi,et al.  Martian North Pole Summer Temperatures: Dirty Water Ice , 1976, Science.

[5]  J. Pollack,et al.  Mechanisms for Mars dust storms. , 1973 .

[6]  B. White,et al.  Mars: Wind friction speeds for particle movement , 1976 .

[7]  H. Kieffer,et al.  Thermal infrared properties of the Martian atmosphere: 3. Local dust clouds , 1979 .

[8]  D. H. Scott,et al.  Geologic map of Mars , 1976 .

[9]  R. Greeley.  Silt-clay aggregates on Mars , 1979 .

[10]  R. Norris.  Barchan Dunes of Imperial Valley, California , 1966, The Journal of Geology.

[11]  R. Greeley,et al.  Some Martian volcanic features as viewed from the Viking orbiters , 1977 .

[12]  W. Ward.  Climatic variations on Mars: 1. Astronomical theory of insolation , 1974 .

[13]  Joshua Lederberg,et al.  Variable features on Mars 2: Mariner 9 global results , 1973 .

[14]  A. Warren.  OBSERVATIONS ON DUNES AND BI‐MODAL SANDS IN THE TÉNÉRÉ DESERT , 1972 .

[15]  Mariner 9 observations of the surface of Mars in the north polar region , 1973 .

[16]  David C. Pieri,et al.  Particle motion on Mars inferred from the Viking Lander cameras , 1977 .

[17]  D. Holm.  Desert Geomorphology in the Arabian Peninsula. , 1960, Science.

[18]  M. Malin,et al.  Climatic variations on Mars: 2. Evolution of carbon dioxide atmosphere and polar caps , 1974 .

[19]  Thomas A. Mutch,et al.  Geology of Mars , 1977 .

[20]  W. Cooper.  Coastal sand dunes of Oregon and Washington , 1958 .

[21]  I. Wilson.  DESERT SANDFLOW BASINS AND A MODEL FOR THE DEVELOPMENT OF ERGS , 1971 .

[22]  Kenneth L. Jones,et al.  The geology of the Viking Lander 1 site , 1977 .

[23]  F. Fanale,et al.  Another Look at Regolith Buffering of Seasonal Atmospheric Pressure Variations on Mars , 1978 .

[24]  Ronald Greeley,et al.  Wind tunnel studies of Martian aeolian processes , 1974, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[25]  C. Leovy,et al.  Mariner 9 observations of the Mars north polar hood , 1974 .

[26]  R Greeley,et al.  North Polar Region of Mars: Imaging Results from Viking 2 , 1976, Science.

[27]  P. James,et al.  Martian extratropical cyclones , 1979, Nature.

[28]  R. Huguenin.  Mars - Chemical weathering as a massive volatile sink , 1976 .

[29]  J. Pollack,et al.  A numerical model of the Martian polar cap winds , 1979 .

[30]  A. W. Ward.  Yardangs on Mars: Evidence of recent wind erosion , 1979 .

[31]  Terry Z. Martin,et al.  Thermal and albedo mapping of Mars during the Viking primary mission , 1977 .

[32]  J. A. Mabbutt.  AEOLIAN LANDFORMS IN CENTRAL AUSTRALIA , 1968 .

[33]  Herman J. Finkel.  The Barchans of Southern Peru , 1959, The Journal of Geology.

[34]  J. Pollack,et al.  Properties and effects of dust particles suspended in the Martian atmosphere , 1979 .