Abstract

MARIN SOSA, Ma. Isabel et al. Modelling of the radiative temperature bidirectional distribution function in agricultural crops. Terra Latinoam [online]. 2013, vol.31, n.4, pp.259-274. ISSN 2395-8030.

The mass and energy exchanges between the biosphere and atmosphere control the water available on the planet; thus, it is important to model these processes. The surface temperature measured by the radiative temperature (Tr) is one of the critical factors in calculations of energy flows. Tr measurements vary depending on sun-sensor geometry. This introduces a further uncertainty factor when Tr is used in the calculation of sensible heat flux instead of aerodynamic temperature. Although the Eddy Covariance technique has been used to directly measure the mass and energy fluxes in the vegetation, the lack of closure in the energy balances do not have a satisfactory explanation. Considering that modeling of sun-sensor geometry includes variation in the influence areas (or footprints) of the measurements, we discuss the need for a common footprint in analyzing energy balance closure. Thus, we introduce a uni-parametric model for Tr (UPMT), originally developed for reflectance, which is validated using data from an experiment conducted in the Sonora Yaqui Valley, Mexico, in five crops with different configurations of sun-sensor geometry and associated footprints. Results show a fine adjustment of MUPT, and it can therefore be used operationally.

Keywords : sensible heat; energy balance closure; MUPT model; footprint; aerodynamic temperature; Eddy Covariance.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )