where \(\varepsilon_{0}\) is the (dimensionless) surface emissivity, σ
the Stefan-Boltzmann constant (5.67×10−8Wm-²K-4) and TS the
surface temperature (K). Emissivity can be calculated based on empirical
equations of the Normalized Difference Vegetation Index (NDVI) and the
leaf area index (LAI). The leaf area index (Eq. 6) is calculated by
using an empirical equation of the Soil Adjusted Vegetation Index (SAVI)
(Allen, Tasumi, Trezza, Bastiaanssen, & Waters, 2002):