红外与毫米波学报, 2011, 30 (1): 61, 网络出版: 2011-02-21
用HJ-1B卫星数据反演地表温度的修正单通道算法
A modified single-channel algorithm for land surface temperature retrieval from HJ-1B satellite data
地表温度 单通道算法 大气辐射传输模型 HJ-1B卫星 land surface temperature single-channel algorithm atmospheric radiative transfer model HJ-1B satellite
摘要
目前用于地表温度反演的单通道算法主要针对窄视场传感器建立.HJ-1B卫星红外相机为宽视场传感器, 其热红外通道(IRS4)观测天顶角可达±33°以上, 在地表温度反演时必须剔除传感器观测角度的影响.以大气辐射传输模拟为基础, 建立了基于传感器观测天顶角-大气函数系数的修正单通道算法.针对HJ-1B卫星与Terra卫星过境时间接近的特点, 提出将MODIS大气水汽含量产品作为单通道算法的输入参数, 并建立了观测天顶角-垂直与斜程大气水汽含量转换系数查找表.基于对光谱数据的模拟, 给出了适用于IRS4通道的地表发射率确定方法.验证结果表明, 修正单通道算法平均反演误差在1.1K以内, 比不考虑传感器观测角度的单通道算法精度提高0.1~0.7K, 反演误差对于传感器观测天顶角依赖性减弱.对实际HJ-1B卫星影像的应用结果表明, 修正单通道算法反演的地表温度与MODIS地表温度产品具有较好的一致性.
Abstract
The currently used single-channel algorithms for land surface temperature (LST) retrieval are mainly proposed for sensors with limited scopes. The coverage of the infrared camera (IRS) onboard HJ-1B satellite is broad, and the view zenith angle of IRS channel 4 can reach ±33°. Therefore, the effects of view angle should be eliminated when retrieving LST with IRS4. Based on atmospheric radiative transfer simulation, this research explored a look-up table for view zenith angle (VZA)-coefficients of atmospheric functions and then proposed an improved single-channel algorithm for estimating LST from IRS4 images. According to the fact that the overpass time of HJ-1B and Terra are very close, the research investigated the possibility to integrate the water vapor provided by MODIS into the improved single-channel algorithm. In addition, this research proposed a practical routine to calculate the land surface emissivity of IRS4. Validation shows that the average absolute error of the improved algorithm is below 1.1K, which is about 0.1~0.7K lower than the algorithm without considering the view zenith angle. Application to the HJ-1B satellite imagery indicated that land surface temperatures retrieved with the improved algorithm are consistent with those provided by MODIS product.
周纪, 李京, 赵祥, 占文凤, 郭建侠. 用HJ-1B卫星数据反演地表温度的修正单通道算法[J]. 红外与毫米波学报, 2011, 30(1): 61. ZHOU Ji, LI Jing, ZHAO Xiang, ZHAN Wen-Feng, GUO Jian-Xia. A modified single-channel algorithm for land surface temperature retrieval from HJ-1B satellite data[J]. Journal of Infrared and Millimeter Waves, 2011, 30(1): 61.