Direct estimation of land-surface diurnal temperature cycle model parameters from MSG-SEVIRI brightness temperatures under clear sky conditions

The land-surface diurnal temperature cycle (DTC) and its model parameters characterize the thermal properties of the land surface. In this study, we propose a method to estimate the diurnal cycle of land surface temperature difference (ΔTs) from the top-of-the-atmosphere brightness temperatures of MSG-SEVIRI channels 9 (10.8 μm) and 10 (12.0 μm). Fitting a DTC model to the diurnal cycle of ΔTs can directly determine the land-surface DTC model parameters without resorting to land surface temperature and emissivity. The performance of the DTC model was evaluated using MSG-SEVIRI pixels over different land cover types. The results show that the fitting accuracy (root mean square error) of the DTC model is better than 1 K for most pixels. The spatial patterns of diurnal temperature range, time of maximum temperature, and attenuation constant were analyzed, and the potential applications of these parameters are presented. These parameters are shown to be related to the physical properties of the land surface and may bring new insight into the estimation of thermal inertia and soil moisture.