Thermal interactions between the underlying surface and a nonstationary radiation flux

The dynamics of interactions between the underlying surface and a varying s olar radiation flux is considered. An analysis of a large body of data on f luctuations in the land surface temperature and the incoming solar radiatio n is indicative of a significant difference between the real dermal charact eristics of the underlying surface and the standard (reference) ones. This difference is due to the thermal properties of soil being are nonuniform in depth. In connection with this, it is concluded that a two-layer model, wh ich represents the underlying surface in the form of a half-space with unif orm thermal properties, is unsuitable for the description of thermal intera ctions between the real surface and the atmosphere. A procedure of an exper imental determination of the thermal properties of the underlying medium is described. This procedure is based on the comparison between the spectra o f fluctuations in the land surface temperature and the incoming solar radia tion. Errors related to the use of the model of a uniform underlying medium are discussed. It is suggested that the procedure described in this paper be used for remote sensing of the thermal properties of real types of the u nderlying surface.