用HJ-1B卫星数据反演地表温度的修正单通道算法

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...

A modified single-channel algorithm for land surface temperature retrieval from HJ-1B satellite data

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 explores a look-up table for view zenith angle (VZA)-coefficients of atmospheric functions and then proposes 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 investigates the possibility to integrate the water vapor provided by MODIS into the improved single-channel algorithm. In addition, this research proposes the 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 0.1K~0.7K lower than the algorithm without considering the view zenith angle. Application to the HJ-1B satellite imagery indicates that land surface temperatures retrieved with the improved algorithm are consistent with those provided by MOD11A1 product.