Interpretation of thermal emission. I. The effect of roughness for spatially resolved atmosphereless bodies
Interpretation of thermal emission. I. The effect of roughness for spatially resolved atmosphereless bodies
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DOI：
10.1016/j.icarus.2014.12.029
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发表时间：
2015-05-15
期刊：
影响因子：
3.2
通讯作者：
Mueller, Thomas G.
中科院分区：
文献类型：
--
作者：
Davidsson, Bjorn J. R.;Rickman, Hans;Mueller, Thomas G.
航天器对无大气层太阳系天体的观测，结合热物理模型，提供了关于这些天体的热惯性和表面粗糙度的重要信息。热物理模型依赖于各种生成地形的方法，最常见的是凹球面部分。在这里，我们比较了一些不同的地形-凹球面段，随机高斯，分形和平行正弦沟槽-各种照明和观看几何形状，表面粗糙度和波长的热发射的属性。我们发现，热发射强烈依赖于粗糙度类型，即使粗糙度是相同的，对于某些照明和观看几何形状。因此，系统地使用任何单一的地形模型可能会导致热惯性和粗糙度水平的偏差。我们概述了在航天器观测过程中可能采用的策略，以解开热惯性，粗糙度和地形类型的水平。我们还比较了数值复杂和耗时的全尺度热物理模型与简化的统计方法，这是相当容易实现和快速运行。我们的结论是，简化的统计方法是类似于热物理模型的情况下，这里测试，这使得用户能够分析大量的光谱数据在一个低的数值成本。(C)2015 Elsevier Inc. All rights reserved.
Spacecraft observations of atmosphereless Solar System bodies, combined with thermophysical modeling, provide important information about the thermal inertia and degree of surface roughness of these bodies. The thermophysical models rely on various methods of generating topography, the most common being the concave spherical segment. We here compare the properties of thermal emission for a number of different topographies - concave spherical segments, random Gaussians, fractals and parallel sinusoidal trenches - for various illumination and viewing geometries, degrees of surface roughness and wavelengths. We find that the thermal emission is strongly dependent on roughness type, even when the degrees of roughness are identical, for certain illumination and viewing geometries. The systematic usage of any single topography model may therefore bias determinations of thermal inertia and level of roughness. We outline strategies that may be employed during spacecraft observations to disentangle thermal inertia, level of roughness and type of topography. We also compare the numerically complex and time consuming full-scale thermophysical models with a simplified statistical approach, which is fairly easy to implement and quick to run. We conclude that the simplified statistical approach is similar to thermophysical models for cases tested here, which enables the user to analyze huge amounts of spectral data at a low numerical cost. (C) 2015 Elsevier Inc. All rights reserved.