Mars CO2 Ice Polar Caps
Mars CO2 Ice Polar Caps
复制标题
火星二氧化碳冰极地帽
DOI：
10.1007/978-94-011-5252-5_20
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发表时间：
1998
期刊：
影响因子：
3.2
通讯作者：
F. Forget
中科院分区：
文献类型：
--
作者：
F. Forget
火星极冠已经被地球观测者观测了两个多世纪。在卡西尼和C.惠更斯，赫歇尔（1784）首先描述了它们的季节特征。从地球上看，它们就像白色明亮的特征，在火星年中逐渐变大。由于火星赤道与轨道平面的倾角为25.1°，火星上的季节与地球上的季节非常相似。通过与地球的类比，大多数观察者认为火星的极冠是由水霜组成的，直到第一个太空探测器到达火星。在1965年水手4号使命任务之后，莱顿和默里（Leighton and Murray，1966）使用了一个简单的热模型来揭示控制火星季节性极冠的过程：在高纬度地区的秋冬季节，当地的表面和大气温度变得足够冷，达到二氧化碳的冰点，而二氧化碳是火星稀薄大气的主要成分。二氧化碳凝结并在地表形成二氧化碳冰沉积物。在特定半球的春季和夏季，季节性的二氧化碳上限升华回到大气中。光谱观测后来证实了二氧化碳的组成（Herr和Pimentel，1969; Larson和Fink，1972）。
The Martian Polar caps have been observed for more than two centuries by terrestrial observers. Following the first observations by J. Cassini and C. Huygens, Herschel (1784) first described their seasonal characteristics. From Earth, they appear like white bright features waxing and waning over a Mars year. Because of the 25.1° inclination of Mars’equator to its orbit plane, the seasons on Mars are much like their terrestrial counterparts. By analogy with the Earth, most observers assumed that the Martian polar caps were composed of water frost, until the first space probes to Mars. Following the Mariner 4 mission in 1965, Leighton and Murray (1966) used a simple thermal model to reveal the processes which control the Martian seasonal polar caps: during the fall and winter seasons at high latitudes, the local surface and atmospheric temperatures become cold enough to reach the frost point of CO2, the major constituent of the thin Martian atmosphere. CO2 condenses and forms CO2 ice deposits on the surface. During the spring and summer seasons in a given hemisphere, the seasonal CO2 cap sublimates back into the atmosphere. Spectroscopic observations later confirmed the CO2 composition (Herr and Pimentel, 1969; Larson and Fink, 1972).