Dust deposition on the Mars Exploration Rover Panoramic Camera (Pancam) calibration targets
Dust deposition on the Mars Exploration Rover Panoramic Camera (Pancam) calibration targets
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DOI：
10.1029/2006je002807
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发表时间：
2007-04-26
影响因子：
4.8
通讯作者：
Landis, Geoffrey A.
中科院分区：
文献类型：
--
作者：
Kinch, Kjartan M.;Sohl-Dickstein, Jascha;Landis, Geoffrey A.
[1]火星探测漫游车使命上的全景相机（Pancam）已经获得了超过20，000张漫游车上Pancam校准目标的图像。分析这一数据集允许的沉积速率和清除两个漫游者的风尘的估计。在最初的150 - 170个太阳日期间，火星车上的灰尘逐渐积累，但没有证据表明灰尘被清除。在那之后，有充分的证据表明，两个漫游者甲板上都有灰尘清除和灰尘沉积。我们分析数据早期在两个漫游任务使用漫反射混合模型。假设尘埃沉降率与大气光学厚度成正比，我们推导出的光谱光学厚层的大气降尘是一致的，从火星表面的尘埃区域的光谱。机遇号站点的大气降尘反射率似乎大于精神号站点，这与其他观测结果一致。我们估计溶胶150沉积在精神校准目标上的灰尘的光学深度为0.44 +/- 0.13。对于机会，该值为0.39 +/- 0.12。假设80%的孔隙空间，我们估计，灰尘层的增长速度为一个颗粒直径每类似于100溶胶的精神校准目标。在机遇号上，速率为每125个溶胶一个粒径。考虑到火星探路者使命期间较低的大气尘埃光学厚度，这些数字与火星探路者观测到的尘埃沉积速率一致。
[1] The Panoramic Camera (Pancam) on the Mars Exploration Rover mission has acquired in excess of 20,000 images of the Pancam calibration targets on the rovers. Analysis of this data set allows estimates of the rate of deposition and removal of aeolian dust on both rovers. During the first 150 - 170 sols there was gradual dust accumulation on the rovers but no evidence for dust removal. After that time there is ample evidence for both dust removal and dust deposition on both rover decks. We analyze data from early in both rover missions using a diffusive reflectance mixing model. Assuming a dust settling rate proportional to the atmospheric optical depth, we derive spectra of optically thick layers of airfall dust that are consistent with spectra from dusty regions on the Martian surface. Airfall dust reflectance at the Opportunity site appears greater than at the Spirit site, consistent with other observations. We estimate the optical depth of dust deposited on the Spirit calibration target by sol 150 to be 0.44 +/- 0.13. For Opportunity the value was 0.39 +/- 0.12. Assuming 80% pore space, we estimate that the dust layer grew at a rate of one grain diameter per similar to 100 sols on the Spirit calibration target. On Opportunity the rate was one grain diameter per similar to 125 sols. These numbers are consistent with dust deposition rates observed by Mars Pathfinder taking into account the lower atmospheric dust optical depth during the Mars Pathfinder mission.