Greenhouse and thermophoretic effects in dust layers: The missing link for lifting of dust on Mars
Greenhouse and thermophoretic effects in dust layers: The missing link for lifting of dust on Mars
复制标题
尘埃层中的温室效应和热泳效应：火星上尘埃上升的缺失环节
DOI：
10.1029/2008gl033799
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发表时间：
2008
影响因子：
5.2
通讯作者：
D. Reiss
中科院分区：
文献类型：
--
作者：
G. Wurm;J. Teiser;D. Reiss
火星大气中有大量的尘埃，并通过从火星表面夹带的物质不断补充。我们发现，在低大气压下对粉尘床进行简单的照明，提供了一种有效地将粉尘颗粒提升到大气中的机制。这种抬升过程是由尘床内的两种微妙影响引起的：温室效应和热泳动。实验室和微重力实验表明，发生升力所需的光通量与火星上可用的太阳日晒相同。这一机制大大降低了风应力对尘埃夹带的阈值，并可能有助于解释火星上总体上有大量悬浮尘埃的原因。具体地说，这种提升过程可能有助于为尘卷风提供必要的初始提升力，并有助于触发更大的沙尘暴。
Dust is abundant in the Martian atmosphere and is continuously replenished by the entrainment of material from the surface of the planet. We find that the simple illumination of a dust bed at low atmospheric pressure provides a mechanism that efficiently lifts dust particles into the atmosphere. This lifting process is caused by two subtle effects within the dust bed: a greenhouse effect and thermophoresis. Laboratory and microgravity experiments show that the light flux needed for lift to occur is in the same range as that of the solar insolation available on Mars. This mechanism significantly lowers the threshold for dust entrainment by wind stress and may help explain the large amount of suspended dust on Mars overall. Specifically, this lifting process may help provide the initial lift necessary for dust devils and help trigger larger dust storms.