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 degrees. Therefore, the effects of view angle should lie 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 1.1 similar to 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 MODES product.