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首页> 外文学位 >The dusty atmosphere of Mars: A study of the properties of martian aerosol dust, using Imager for Mars Pathfinder and Hubble Space Telescope observations.
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The dusty atmosphere of Mars: A study of the properties of martian aerosol dust, using Imager for Mars Pathfinder and Hubble Space Telescope observations.

机译：火星尘土飞扬的大气：使用成像仪对火星探路者和哈勃太空望远镜进行观测，研究火星气溶胶尘埃的特性。

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摘要

The properties of aerosol dust on Mars may be deduced from photometric observations of its atmosphere. By comparing sky images taken by the Imager for Mars Pathfinder to numerical models, the size distribution and reflective properties of the dust particles can be determined. The format, quality, and reduction of the IMP images is described herein, as is the computational radiative transfer model used, with its various parameters. After discovering and compensating for an imprecision in the pointing of the camera, models were successfully fit to the IMP solar aureole datasets. Key results include determining the particle size (reff = 1.6 +/- 0.15 mum); quadratic parameters G and thetamin describing the phase function for internally scattered light as functions of wavelength; and the imaginary refractive index n i (and single scattering albedo o) of the aerosols as a function of wavelength (presented in Table 4.1). Preliminary indications of temporal variation in ni turn out to be due to an unplanned change in the time of day of the measurements, coupled with a limitation in the algorithm for correcting the aforementioned pointing imprecision. Excluding unreliable datasets leads to a set of particle properties which shows no significant variation over the first two months of the Pathfinder mission. A multispectral sky patch from MPF Sol 22 gives greater wavelength resolution, as well as showing the sensitivity of the results to variations in key model parameters. In addition, images from the Hubble Space Telescope are used to refine the surface reflectance used in the model. The final result is a model for the aerosol dust which is consistent with the IMP solar aureole observations and the HST observations. Evidence for a minor component of water ice is also discussed. Dust reflectances derived for comparison with ground spectra show a feature in the near infrared which is not present in most MPF spectra of bright surface regolith. This is an indication that there are components visible in the bright soil which are not present in the airborne dust.
机译：火星上的气溶胶粉尘的特性可以通过对大气的光度观测来推导。通过将“火星探路者”热像仪拍摄的天空图像与数值模型进行比较，可以确定灰尘颗粒的尺寸分布和反射特性。这里描述了IMP图像的格式，质量和缩小，以及所使用的具有各种参数的计算辐射传递模型。在发现并补偿了相机指向的不精确性之后，模型成功地适合了IMP太阳金极数据集。关键的结果包括确定粒径（reff = 1.6 +/- 0.15微米）；二次参数G和thetamin描述了内部散射光的相位函数与波长的函数；气溶胶的虚构折射率n i（和单散射反照率o）与波长的关系（表4.1）。 ni中的时间变化的初步指示被证明是由于测量的一天中的时间的计划外变化，以及用于校正上述指向不精确性的算法中的限制。排除不可靠的数据集会导致一组粒子属性，这些属性在“探路者”任务的前两个月内没有显着变化。 MPF Sol 22的多光谱天空斑块提供了更大的波长分辨率，并显示了结果对关键模型参数变化的敏感性。此外，使用哈勃太空望远镜的影像来完善模型中使用的表面反射率。最终结果是气溶胶粉尘模型，该模型与IMP太阳金极观测和HST观测一致。还讨论了水冰中微量成分的证据。为与地面光谱进行比较而得出的粉尘反射率显示出近红外的特征，这在大多数明亮的表面硬石的MPF光谱中都不存在。这表明在明亮的土壤中可见的成分在空气中的粉尘中不存在。

著录项

  • 作者

    Wegryn, Eric.;

  • 作者单位

    The University of Arizona.;

  • 授予单位 The University of Arizona.;
  • 学科 Physics Atmospheric Science.; Physics Astronomy and Astrophysics.
  • 学位 Ph.D.
  • 年度 2000
  • 页码 158 p.
  • 总页数 158
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 大气科学（气象学）;天文学;
  • 关键词

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