Analysis of cloud optical thickness and effective radius retrievals for broken cloud fields
Analysis of cloud optical thickness and effective radius retrievals for broken cloud fields
复制标题
破碎云场云光学厚度及有效半径反演分析
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
R. Welch
中科院分区：
文献类型：
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作者：
R. Feind;R. Welch
两个波长（即可见光和近红外）的辐射传输模型结果可应用于卫星图像，以推断云的光学特性。在这项研究中，作者考察了几种类型的云场，以了解破碎云对云属性检索的影响。可以对水面上的大尺度层状云场进行可靠的云性质估计。即使对于光学厚度较薄（/spl τ /<10）的水面上破碎的云场也是如此。然而，对于大陆晴朗天气的积云场，情况并非如此。三维云效应导致测量反射率和模拟反射率之间的显著差异。作者还研究了空间分辨率对云属性检索的影响。用高空间分辨率影像模拟低空间分辨率仪器获取的影像，滤除了三维云效应，后续检索结果较为合理；然而，由于反射率和光学性质之间的非线性关系，可能会有一些偏倚
Radiative transfer model results at two wavelengths (i.e., visible and near IR) can be applied to satellite imagery to infer optical properties of clouds. In this study, the authors examine several types of cloud fields to gain an understanding of the effect of broken cloudiness on cloud property retrievals. Reliable estimates of cloud properties can be obtained for large scale, stratiform cloud fields over water. The same appears to be true even for optically thin (/spl tau/<10), broken cloud fields over water. However, such is not the case for continental fair weather cumulus cloud fields. Three-dimensional cloud effects cause significant disagreement between measured and modelled reflectance. The authors also examine the effects of spatial resolution on cloud property retrievals. When simulating imagery obtained by a low spatial resolution instrument with their high spatial resolution imagery, the 3D cloud effects are filtered out and subsequent retrievals appear reasonable; however, because of the nonlinear relationship between reflectance and optical properties, some bias is likely.<<ETX>>