Land Surface Temperature Retrieval from HJ-1B Satellite Thermal Infrared Data and Error Analysis with Partial Differential Equation

In this study, we retrieved the land surface temperature (LST) of Guangzhou on Jan 14, 2013. The retrieval was based on the characteristics of HJ-1B thermal infrared band, adopting a revised QK & B algorithm. The established partial differential equation showed that the emissivity error of 0.01 resulted in a LST error of around 0.6 K. The LST error was negatively correlated to the atmospheric transmittance and positively correlated to the atmospheric transmittance error; the transmittance error of 0.1 resulted in a LST error of around 1 K. Meanwhile, the atmospheric water vapor error and the LST error exhibited a linear relation; the atmospheric water vapor error of 0.1 g/cm² resulted in LST error of around 0.2 K. The LST retrieval error was positively correlated to both the near-surface air temperature error and the average atmospheric error; the near-surface air temperature error of 1 K led to the LST retrieval error of around 1 K. Overall, the LST retrieval error and interval ratio are related to the average atmospheric temperature error as well as the near-surface air temperature error. The retrieved land surface temperature of Guangzhou was in strong spatial accordance with the MOD11_L2 LST product. The temperature difference curve exhibited a normal distribution, concentrated in the range of -0.9℃ to 0.9℃. Six ground measurement spots in Guangzhou were chosen to compare the LST obtained by the revised QK & B algorithm with the ground measured average surface temperature. The difference between the LST obtained using the algorithm and the measured ground temperature was around 0.31 K, whereas the MOD11_L2 product had a difference of around 0.65 K with the measured surface temperature, both were less than 1 K. By deriving the partial differential equation of the revised QK & B algorithm, a more detailed and precise analysis was performed on LST retrieval in HJ-1B/IRS. This study also provides a reference for other similar LST retrieval algorithms based on environmental satellite thermal infrared band, as well as a scientific basis for future improvement of LST retrieval accuracy.