Physics of Wind-blown Sand and the Threshold Wind Speed of Dust Storms on Mars
-
摘要: 通过建立风吹动地表沙粒运动的模型并根据大气湍流边界层风速廓线规律,计算了火星上沙尘暴的起动风速和沙尘暴发生时空中悬浮沙尘粒径的大小,并对沙粒从地面跳起进入气流的方式进行了验证.发现当大气为中性层结时,火星沙尘暴的起动需要离地面2m高处的风速达到28.7m·s-1.在起动临界风速下,地表沙粒需要滚动一个粒径的距离才能跳起,沙尘暴发生后,火星大气中悬浮沙尘的粒径小于30μm.Abstract: The planet Mars is most closely related to Earth in its size and character. From the comparative planetology point of view, what happens on the Mars is of importance to our human being on the Earth. There exist dust storms on both Earth and Mars. The dust storm on Mars is different from that on Earth in its scale. However, in some aspects, they are similar on these two planets, like the mechanism for the generation of dust storm. In this paper, a model of wind-blown sand at the surface of sanded ground is constructed, and the threshold wind speed for dust storms to start on Mars is calculated based on the wind profile of atmospheric turbulent boundary layer. It is concluded that the wind speed of 28.7 meters per second at 2 meters height is needed for a dust storm to start on Mars, and the suspended dust particles' diameter is less than 30 micron when wind speed is at the threshold value. It is also found that sands need to roll a distance of one particle's diameter before saltation.
-
Key words:
- Mars /
- Dust storm /
- Wind-blown sand /
- Saltation /
- Threshold wind speed
-
[1] Gifford F A. A study of Martian yellow clouds that display movement[J]. Monthly Weather Rev., 1964, 92(10):435-440 [2] Steinbacher R H, Kliore A, Lorell J, et al. Mariner 9 science experiments: Preliminary results[J]. Science, 1972, 175(1):293-294 [3] Cantor B A, James P B, Caplinger M, Wolff M J. Martian dust storms: 1999 Mars Orbiter Camera observations[J]. J. Geophys. Res., 106(E10):23653-23687 [4] Huiqun Wang. Dust storms originating in the northern hemisphere during the third mapping year of Mars Global Surveyor[J]. Icarus, 2007, 189(1):325-343 [5] Smith M D, Conrath B J, Pearl J C, Christensen P R. Thermal emission spectrometer observations of Martian planet-encircling dust storm 2001A[J]. Icarus, 2002, 157(1):259-263 [6] Strausberg M J, Wang H, Richardson M I, et al. Observations of the initiation and evolution of the 2001 Mars global dust storm[J]. J. Geophys. Res., 2005, 110(E02006) [7] Cantor Bruce A. MOC observations of the 2001 Mars planet-encircling dust storm[J]. Icarus, 2007, 186(1):60-96 [8] Christensen P R, Bandfield J L, James F, et al. Morphology and composition of the surface of Mars: Mars Odyssey THEMIS results[J]. Science, 2003, 300(1):2056-2060 [9] Kelly N J, Boynton W V, Kerry K, et al. Seasonal polar carbon dioxide frost on Mars: CO2 mass and columnar thickness distribution[J]. J. Geophys. Res., 2006, 111(E03S07) [10] Toigo A D, Richardson M I, Wilson R J, et al. A first look at dust lifting and dust storms near the south pole of Mars with a mesoscale model[J]. J. Geophys. Res., 2002, 107(E7):5050 [11] Zurek R W, Martin L J. Interannual variability of planet-encircling dust storms on Mars[J]. J. Geophys. Res., 1993, 98(1):3247-3259 [12] Magalhaes J A, Young R E. Downslope windstorms in the lee of ridges on Mars[J]. Icarus, 1995, 113(2):277-294 [13] Bagnold R A. The Physics of Blown Sand and Desert Dunes[M]. London: Methuen, 1941 [14] Greeley Ronald, Iversen James D. Wind as a Geological Process on Earth, Mars, Venus and Titan[M]. Oxford: Cambridge University Press, 1985 [15] Clift R, Gauvin W H. Motion of entrained particles in gas streams[J]. Can. J. Chem. Eng., 1971, 49(1):439 [16] Chepil W S. The use of evenly spaced hemispheres to evaluate aerodynamic forces on a soil surface[J]. Trans. Am. Geophys. Univ., 1958, 39(1):379 -
-
计量
- 文章访问数: 3323
- HTML全文浏览量: 119
- PDF下载量: 1180
-
被引次数:
0(来源:Crossref)
0(来源:其他)
下载:
