Viking Radio Occultation Measurements of the Martian Atmosphere and Topography: Primary Mission Coverage
Viking Radio Occultation Measurements of the Martian Atmosphere and Topography: Primary Mission Coverage
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DOI：
10.1029/js082i028p04317
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发表时间：
1977-09
影响因子：
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通讯作者：
G. Fjeldbo;D. Sweetnam;J. Brenkle;E. Christensen;D. Farless;J. Mehta;B. Seidel;W. H. Michael
中科院分区：
文献类型：
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作者：
G. Fjeldbo;D. Sweetnam;J. Brenkle;E. Christensen;D. Farless;J. Mehta;B. Seidel;W. H. Michael
1976年10月期间，利用维京海盗号轨道器1 S（2.3 GHz）和X（8.4 GHz）波段跟踪链路在火星上大约50个地点进行了无线电掩星测量。这些测量已被用于研究火星在南纬75 °至北纬70 °之间的地形和大气。通过使用从观测到的边缘衍射效应获得的进入和离开时间，以及轨道飞行器和行星的最佳星历，我们确定了掩星点相对于参考星网的表面高程。观测结果与水手9号和雷达数据在2公里范围内一致。在北方仲夏季节，在弧面层的平均大气压力为5.9毫巴，这个值与在着陆点获得的数据相当吻合。通过将新的电子密度测量结果与早期的水手号数据进行比较，我们确定了高层大气的温度和等离子体尺度高度似乎是太阳活动的函数。
Radio occultation measurements were made at approximately 50 locations on Mars with the Viking Orbiter 1 S (2.3 GHz) and X (8.4 GHz) band tracking links during October 1976. The measurements have been used to study the topography and atmosphere of Mars at latitudes ranging from about 75°S to 70°N. By using the ingress and egress times obtained from the observed limb diffraction effects together with the best ephemerides available for the orbiter and the planet we have determined the surface elevations at the occultation points relative to the reference areoid. The observations agree with Mariner 9 and radar data to within 2 km. The mean atmospheric pressure at the areoid level was found to be 5.9 mbar during the northern midsummer season, a value which agrees quite well with data obtained at the landing sites. By comparing the new electron density measurements with earlier Mariner data we have determined that the temperature and the plasma scale height of the upper atmosphere appear to be functions of solar activity.