Retrieval of cloud geometrical parameters using remote sensing data
Retrieval of cloud geometrical parameters using remote sensing data
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DOI：
10.1117/12.416961
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发表时间：
2001-02
期刊：
影响因子：
--
通讯作者：
M. Kuji;T. Nakajima
中科院分区：
文献类型：
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作者：
M. Kuji;T. Nakajima
对云的光学、微物理和几何参数的研究，特别是对影响全球气候系统的低空海洋云的研究，具有重要意义。云的几何参数为云层的顶高、底高和几何厚度。这些参数是非常重要的检索，因为顶部和底部的高度是控制温室效应的强度，通过热辐射从/到云层的因素，而几何厚度是在云层中的气体吸收的估计，其中多次散射过程占主导地位的关键参数。本文提出了一种利用可见光、近红外、热红外和氧气A波段光谱信息同时反演云光学厚度、有效粒子半径、云顶高度和云层几何厚度的算法。将该算法应用于FIRE（First ISCCP Regional Experiment，1987）机载资料，该资料包括上述四个通道，目标是夏季加州沿海的低空海洋云。反演的结果似乎是可比的，在现场微物理观测，但云的几何参数，特别是需要进一步的验证研究。
It is of great interest to investigate the properties on the cloud optical, microphysical, and geometrical parameters, in particular, of low-level marine clouds which play crucial influence on the global climate system. Top height, base height, and geometrical thickness of cloud layer are considered here as cloud geometrical parameters. These parameters are very important to retrieve, because top and base heights are the factors which govern the strength of greenhouse effect through the thermal radiation from/to cloud layer, whereas the geometrical thickness is the key parameter for the estimation of gaseous absorption in cloud layer where multiple scattering process dominates. In this study, an algorithm was developed to retrieve simultaneously cloud optical thickness, effective particle radius, top height, and geometrical thickness of cloud layer from the spectral information of visible, near infrared, thermal infrared, and oxygen A band channels. This algorithm was applied to FIRE (First ISCCP Regional Experiment, 1987) airborne data which included the above four channels and targeted at the low-level marine clouds off the coast of California in summer. The retrieved results seems to be comparable to the in situ microphysical observation although further validation studies are required for the cloud geometrical parameters in particular.