Fusion of All-Weather Land Surface Temperature From AMSR-E and MODIS Data Using Random Forest Regression

Abstract

On the basis of preceding study of microwave (MW) land surface temperature (LST) downscaling, this letter proposed an all-weather LST fusion method based on random forest (RF) and evaluated it using the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) LSTs in four areas of China that represent different landscapes. The results show that the RF method can effectively avoid the problem of oversmoothing patterns derived by the widely used Bayesian maximum entropy (BME) method and obtained LSTs more consistent with reality. Taking MODIS LST in the Yunnan–Guizhou Plateau (YGP) region and the border of Shanxi Province and Henan Province (BSH) region as a reference, the accuracy of RF method improved up to 13% and 11% compared with those of BME method under different cloud proportions. Taking field observations in the Heihe River Basin (HRB) and the Naqu area as references, the accuracy of RF-derived LST under cloudy conditions is basically consistent with that of MODIS LST in clear sky, differing by only 0.004–0.067 K. Due to the introduction of environmental variables, the performance of RF method is more stable than that of the BME method under different cloud proportions. In summary, RF is promising for fusing MW and thermal infrared (TIR) LSTs.