The use of the apparatus of nonadditive statistical mechanics for the evaluation of thermodynamic ecosystem variables based on multispectral measurements of reflected solar radiation is discussed. The parameter q is accepted corresponding to the conditions of the Förster’s maximum of organization. On the basis of remote information (Landsat) the entropy, Kullback information, Förster measure of organization, free energy, exergy, bound and internal energy, energy costs for evapotranspiration and photosynthesis for q-index values measured for each pixel of remote sensing scenes. It is shown that the seasonal dynamics of the q-index and the organization measures fully correspond to consequences that follow from the theory of open nonequilibrium systems, and thermodynamic variables reflect well the current state of ecosystems.