Improved split window algorithm to retrieve LST from Terra/MODIS data

Abstract

This paper presents an algorithm for the retrieval of daytime land surface temperature (LST) from the Terra/MODIS data, which considers the atmospheric radiation effects due to the viewing zenith angle (VZA) variation. The MODTRAN4 model, 875 profiles of TIGR3 database and 106 surface emissivity spectra of the ASTER spectral library were used to obtain the Split-Window Algorithm (SWA) coefficients. The Root Mean Square Errors (RMSEs) of LST retrieval using the MODTRAN4 simulation are 034 K. Sensitivity analysis confirmed that the algorithm is not sensitive to total column water vapor content (TCWVC) for the moderately moist atmospheric conditions. In addition, LST retrieval error due to the VZA effect was reduced. Retrieved LSTs have compared with Mao, et al.'s LST and MODI 1-L2 LST. Surface Radiation (SURFRAD) budget network measurements have been used for LST validation over six sites during the entire month of June 2009. The RMSE values of LST were 0.93 K, 1.49 K and 1.0 K for this new algorithm, Mao, et al.'s algorithm and MODI 1-L2 LST, while the average biases were -0.66 K, 1.34 K and -0.38 K, respectively.