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.