火星上的雪深度的季节性变化
D E Smith1, M T Zuber, G A Neumann
1Laboratory for Terrestrial Physics, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA.
概括
火星 火星 火星 火星 火星
科学领域:
- 行星科学 行星科学
- 地质物理学 地质物理学
背景情况:
- 火星的季节性二氧化碳循环影响了火星表面的升高和行星的平整.
- 之前的研究缺乏对这些时间变化的精确测量.
研究的目的:
- 为了量化火星的季节性海拔变化.
- 为了确定季节性沉积的二氧化碳的密度.
- 为了研究火星重力和地形之间的关系.
主要方法:
- 利用火星轨道器激光高度计 (MOLA) 在火星全球测量器 (MGS) 飞船上的地形数据.
- 分析了MGS多普勒追踪残留物以测量火星平面化的时间变化.
- 与季节性二氧化碳交换相关的海拔变化.
主要成果:
- 在高火星度 (80度以上) 测量了显著的海拔变化 (1.5-2米).
- 在北半球秋季观察到一个意想不到的升华期,与南半球沙尘暴相吻合.
- 限制季节性沉积二氧化碳的平均密度为910 +/- 230 kg/m3.
结论:
- 季节性二氧化碳沉积和升华导致火星上可测量的海拔变化.
- 火星干冰的密度明显高于地球上的雪.
- 火星的重力和平面化的时间变化与表面过程有关.
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