Statistical modelling of laser induced fluorescence in plant cover

A system of mutually coupled radiative transfer equations is proposed as a formal basis for the numerical analysis of a broad range of spectroscopic effects associated with the propagation of laser radiation in the environment. In particular, this concerns the reabsorption of laser induced fluorescence which inevitably occurs in dense disperse media containing two or more fluorophors. One practical application is for the pressing problem of lidar monitoring the state of plant cover, in particular the concentration of chlorophyll, which regulates the vital activity of plants. A new concept for an optical model of plant cover has been developed in which leaves are not treated as separate scattering elements, but as local volumes of a multiphase medium with a complex polydisperse structure. A modified Monte-Carlo algorithm is created for imitating the fluorescence and reabsorption processes. Test calculations confirm the adequacy of this approach. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 411–418, May–June, 2009.