Angular effect of MODIS emissivity products and its application to the split-window algorithm
Angular effect of MODIS emissivity products and its application to the split-window algorithm
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MODIS发射率产品的角效应及其在分窗算法中的应用
DOI：
10.1016/j.isprsjprs.2011.02.008
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发表时间：
2011-07-01
影响因子：
12.7
通讯作者：
Li, Zhaoliang
中科院分区：
文献类型：
--
作者：
Ren, Huazhong;Yan, Guangjian;Li, Zhaoliang
当前的地表温度 (LST) 产品忽略了发射率的角度效应。因此，这些LST产品的方向性限制了它们在许多领域的进一步应用。精确校正 LST 产品的角度问题需要明确了解像素尺度发射率的角度效应。目前MODIS已有近十年的全球发射率产品。然而，发射率的像素尺度方向性从未被分析过。通过对东亚大部分地区的 5 年 MODIS 发射率产品进行统计分析，我们生成了定向发射率、土地覆盖和季节变化之间的经验关系。针对典型的土地覆盖类型创建了两个定向发射率查找表 (LUT)，并将其应用于广义分窗算法以修改 MODIS LST。结果表明，发射率的角度效应会给1 km分辨率LST带来-1-3 K的显着偏差。最后，分析了发射率的空间尺度效应，发现在1 km LST反演中使用5 km发射率时，大多数像元因尺度效应引起的温度差异在+/-0.5 K以内。因此，LUT 的广泛使用是可以预期的。 (C) 2011 年国际摄影测量和遥感协会 (ISPRS)。由 Elsevier B.V. 出版。保留所有权利。
The angular effects of emissivity are ignored in current land surface temperature (LST) products. As a result, the directionality of these LST products limits their further application in many fields. Accurate correction of the angular problem of LST products requires explicit understanding of the angular effects of emissivity at the pixel scale. Currently, nearly ten years of global emissivity products of MODIS are available. However, the pixel-scale directionality of emissivity has never been analyzed. By performing a statistical analysis of 5-year MODIS emissivity products over most of East Asia, we generated the empirical relationships between the directional emissivity, land cover, and seasonal variations. Two look-up tables (LUTs) of directional emissivity were created for typical land cover types and applied to the generalized split-window algorithm to modify the MODIS LST. The results showed that the angular effect of emissivity could introduce a significant bias of -1-3 K to the 1 km resolution LST. Finally, the spatial scale effects of emissivity were analyzed, and it was found that the temperature differences caused by scale effects fell within +/-0.5 K for most pixels if 5 km emissivity was used in 1 km LST retrieval. Therefore, wide use of the LUTs can be expected. (C) 2011 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved.