Sun-induced leaf fluorescence retrieval in the O2-B atmospheric absorption band

Sun-induced leaf fluorescence was inferred by using high resolution (0.5 cm-1) radiance measurements and simulated spectra of the solar irradiance at the ground level, in the region of the O2-B absorption band. The minimization of a cost function was performed in the Fourier transform domain in order to make an accurate fit of the Instrumental Line- Shape that convoluted the simulated spectrum. Second- order polynomials were used to fit the leaf fluorescence and reflectance in the 100-cm-1-wide spectral window. The scale and the instrumental conversion factor were also fitted in order to obtain an accuracy that could not be attained by using the radiance measurements alone.