摘要:本文运用CloudSat卫星上搭载的雷达探测数据和AQUA卫星搭载的辐射光谱仪探测数据，选择2007年1月至2010年12月期间，地理位置位于（15°~45°N，145°~165°E）区域内（远海）发生的云场数据开展分析，研究云的物理结构特征与其光谱辐射特性的相互关系。不同光谱波段对云物理结构变化的响应情况各有不同，首先从MODIS光谱仪22个云相关光谱波段中分析并选择出与云物理结构特征密切相关的光谱组合（包含13个波段），而后开展了这些光谱波段的云辐射特性与云物理结构特征的相互变化关系研究。统计分析表明，在外部大气、地表条件以及太阳入射辐射变化不大情况下，云的结构变化与其光谱辐射变化之间总体存在单调相关关系，物理结构变化不大的云廓线之间其光谱辐射的变化也小，反之也成立，即光谱辐射变化小的云廓线之间物理结构变化也小。从而，对于某些内部物理结构特征未知的云，利用与其光谱辐射特性相近的云结构数据可实现自身垂直结构信息的重建。基于光谱辐射相近则云物理结构很可能相近的特点，本文对未知云场的物理结构重建开展了模拟试验，试验结果表明光谱相近原则匹配物理结构的方法一定程度上能够实现云物理结构的构建，为利用被动遥感数据推测云物理结构特征研究提供参考。
关键词:MODIS光谱仪/
CloudSat卫星/
垂直结构/
三维云/
辐射
Abstract:Radars can actively detect cloud internal physical structure while radiometers can passively measure the integral radiation characteristics of clouds. This study uses cloud products from CloudSat (active detection) and AQUA (passive detection) during the period from 1 January 2007 to 31 December 2010 over the area (15°-45°N, 145°-165°E) to study the relationships between the variations of radiation characteristics and the physical structure characteristics of clouds. MODIS (MODerate-resolution Imaging Spectroradiometer) uses 22 wavebands that have various sensitivities to cloud physical properties to measure radiation from cloud. Firstly, 13 wavebands demonstrating high correlation with the cloud physical structures are screened out based on correlation analysis. Then, the relationship between the radiation variations of these 13 wavebands and changes in the cloud physical structures are studied. Statistical analysis shows that the variation in cloud radiation illustrates a monotonic change with the variation in cloud physical structures when conditions (e.g., atmospheric environment, surface characteristics) change little. This means two cloud profiles with close radiative properties may also have similar physical structures. For some cloud profiles with unknown internal structures, their vertical structures can be inferred from other cloud profiles with similar spectral radiative properties. Preliminary tests for reconstructing the cloud vertical structure are performed and it is found that cloud physical structures constructed based on the nearest radiative characteristics principle are close to the structures measured by radars.
Key words:MODIS (MODerate-resolution Imaging Spectroradiometer)/
CloudSat satellite/
Cloud structure/
3D cloud/
Radiation
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