Relationship between Terra/ASTER Land Surface Temperature and Ground-observed Air Temperature

This study estimated near-ground air temperature (Ta) from Terra/ASTER-obtained land surface temperature (LST) for different land cover categories in a hilly region under a clear and calm night in winter. Temperature differences (ΔT) between LST and Ta were related to the land cover categories and their spatial extents. In the extended area of forest land, spatially averaged ΔT in the area (ΔTm) was −0.1°C, and the relationship between LST and Ta showed less variability (standard deviation of ΔT (SD)=0.8°C) and high correlation (coefficient of determination between Ta and LST (R2)=0.70). This result suggests we can evaluate Ta directly from LST in this area. In the extended area of bare land, ΔTm, SD and R2 were −1.5°C, 0.9°C and 0.85, respectively, which indicated that accurate estimation of Ta is possible by correcting LST by ΔTm. In the extended area of artificial land, ΔTm showed statistically non-significant trend. In the case of intermingled area of more than one type of land cover, ΔTm, SD and R2 were −0.8°C, 0.9°C and 0.71 in the forest land of the intermingled area, which suggested that we can estimate Ta in this area precisely by correcting LST by ΔTm. In the bare land of the intermingled area, though ΔTm was −1.4°C, large variations (SD=1.4°C) and low correlations (R2=0.33) were found.