用于星载太赫兹波被动遥感卷云参数的通道辐射特性及反演影响因素研究
投稿时间:2017-06-07  修订日期:2017-08-16  点此下载全文
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作者单位E-mail
李书磊 陆军工程大学电磁环境效应与电光工程国家级重点实验室 lishulei91@gmail.com 
刘磊 国防科技大学气象海洋学院 liuleidll@gmail.com 
高太长 国防科技大学气象海洋学院  
石立华 陆军工程大学电磁环境效应与电光工程国家级重点实验室  
邱实 陆军工程大学电磁环境效应与电光工程国家级重点实验室  
胡帅 国防科技大学气象海洋学院  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:太赫兹波是理论上遥感卷云微物理参数的最佳波段,但星载太赫兹波被动遥感的结果易受到非卷云因素(地表反射率、大气廓线、中低层水云等)的影响。为了评估这些因素对多重查找表反演方法造成的误差,利用辐射传输模式分别模拟计算了地表反射率、大气廓线、中低层水云对大气层顶太赫兹辐射光谱的影响,并基于多重查找表法定量分析了这些因素的变化所造成的反演误差。结果表明:地表反射率对太赫兹辐射光谱的影响主要集中在300GHz以下,对反演所选取的波段没有影响;实际大气廓线中水汽廓线和温度廓线的改变对反演结果产生影响,当温度廓线的变化在2K范围以内,或水汽廓线变化20%时,对于粒子尺度大于50μm、冰水路径大于10g/m2的卷云,反演误差均保持在20%以内;低云(云底高小于2km)对所选通道的辐射没有影响,中云所产生的误差随着光学厚度和云底高度的增加而增大。
中文关键词:卷云  大气廓线  水云  反演误差
 
Study on the radiation characteristics of the selected channels for cirrus remote sensing in terahertz waveband and the influence factors for the retrieval method
Abstract:Terahertz is expected to be the best waveband for remote sensing of cirrus. However, the retrieval results of satellite terahertz passive remote sensing are susceptible to different atmospheric conditions and environments. In order to evaluate the effects of the atmosphere non-cirrus factors (mainly the surface reflectivity, atmospheric profiles, the middle-low level water clouds) on the retrieval results, the terahertz radiation were simulated under the clear sky and the cloudy situations, based on the atmospheric radiative transfer simulator. The influences of the surface reflectivity, atmospheric profiles and the middle-low level water clouds to terahertz radiation were analyzed. The retrieval errors caused by these factors were calculated based on the multiple lookup tables method. The results indicate that the influence caused by changing the surface reflectivity mainly range below 300GHz, and there is no influence for the retrieval channels. Among the atmospheric profiles, only the changing of water vapor profiles and temperature profiles have effects on the retrieval results. When the temperature profile changes are between 2K, or the water vapor profile changes are between 20%, for cirrus whose particle size is above 50μm and ice water path is above 10g/m2, the retrieval errors stay below 20%. For low-level water clouds (cloud base height below 2km), the effects on retrieval errors can be ignored. The retrieval errors caused by middle-level water clouds increase with the increases of the cloud base height and cloud optical depth.
keywords:cirrus, atmospheric profiles, water clouds, retrieval errors
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