Estimation of Sensible and Latent Heat Fluxes from Soil Surface Temperature Using a Linear Air-Land Heat Transfer Model

The authors present a linearized model of the heat transfer between the soil layer and the atmosphere. Using this model, the moisture availability at the surface can be estimated from the diurnal variations of the soil surface temperature and downward radiation, when the bulk exchange coefficient is given. The model can also estimate the diurnal variations of the sensible and latent heat fluxes. If the moisture availability is known, the bulk exchange coefficient can be estimated in a similar manner. Two different methods are presented. The first method estimates the moisture availability from the difference between the daily mean air temperature and soil surface temperature. The second method can estimate the moisture availability from the daily variation of the soil surface temperature alone, without use of the air temperature. The accuracy of the heat fluxes by the second method is still quite high, even if they are estimated from the soil surface temperatures observed only twice daily. These methods are available only on bare-soil surfaces.