Cao Ya-nan, Wei He-li, Dai Cong-ming, Zhang Xue-hai
Guang Pu Xue Yu Guang Pu Fen Xi. 2015 May;35(5):1208-13.
A study was carried out to retrieve optical thickness and cloud top height of cirrus clouds from the Atmospheric Infrared Sounder (AIRS) high spectral resolution data in 10701135 cm-1 IR band using a Combined Atmospheric Radiative Transfer model (CART) by brightness temperature difference between model simulation and AIRS observation. The research is based on AIRS LIB high spectral infrared observation data combined with Moderate Resolution Imaging Spectroradiometer (MODIS) cloud product data. Brightness temperature spectra based, on the retrieved cirrus optical thickness and cloud top height were simulated and compared with brightness temperature spectra of AIRS observation in the 6501150 cm-1 band. The cirrus optical thickness and cloud top height retrieved were compared with brightness temperature of AIRS for channel 760 (900.56 cm-1, 11. 1 µm) and cirrus reflectance of MODIS cloud product. And cloud top height retrieved was compared with cloud top height from MODIS. Results show that the brightness temperature spectra simulated were basically consistent with AIRS observation under the condition of retrieval in the 6501150 cm-1 band. It means that CART can be used to simulate AIRS brightness temperature spectra. The retrieved cirrus parameters are consistent with brightness temperature of AIRS for channel 11. 1 µm with low brightness temperature corresponding to large cirrus optical thickness and high cloud top height. And the retrieved cirrus parameters are consistent with cirrus reflectance of MODIS cloud product with high cirrus reflectance corresponding to large cirrus optical thickness and high cloud top height. Correlation coefficient of brightness temperature between retrieved cloud top height and MODIS cloud top height was relatively high. They are mostly located in the range of 8. 511.5 km, and their probability distribution trend is approximately identical. CART model is feasible to retrieve cirrus properties, and the retrieval is reliable.
利用联合大气辐射传输模型（CART），通过模型模拟与大气红外探测器（AIRS）观测之间的亮温差，对10701135厘米-1红外波段的AIRS高光谱分辨率数据进行了一项研究，以反演卷云的光学厚度和云顶高度。该研究基于AIRS LIB高光谱红外观测数据，并结合了中分辨率成像光谱仪（MODIS）云产品数据。基于反演得到的卷云光学厚度和云顶高度模拟了亮温光谱，并与6501150厘米-1波段的AIRS观测亮温光谱进行了比较。将反演得到的卷云光学厚度和云顶高度与AIRS通道760（900.56厘米-1，11.1微米）的亮温和MODIS云产品的卷云反射率进行了比较。并且将反演得到的云顶高度与MODIS的云顶高度进行了比较。结果表明，在6501150厘米-1波段反演条件下，模拟的亮温光谱与AIRS观测基本一致。这意味着CART可用于模拟AIRS亮温光谱。反演得到的卷云参数与AIRS通道11.1微米的亮温一致，亮温较低对应较大的卷云光学厚度和较高的云顶高度。并且反演得到的卷云参数与MODIS云产品的卷云反射率一致，高卷云反射率对应较大的卷云光学厚度和较高的云顶高度。反演得到的云顶高度与MODIS云顶高度之间的亮温相关系数较高。它们大多位于8.511.5千米范围内，其概率分布趋势大致相同。CART模型反演卷云特性是可行的，且反演结果可靠。
