There is growing interest to use sun induced fluorescence to estimate ecosystem photosynthesis from space. This new paper from Yang et al tested indices from hyper spectral reflectance measurements with gross carbon fluxes at Harvard forest. Results look interesting and the response between SIF and GPP is much more linear than that between GPP and NDVI or EVI
Yang, X., J. W. Tang, J. F. Mustard, J. E. Lee, M. Rossini, J. Joiner, J. W. Munger, A. Kornfeld, and A. D. Richardson. 2015. Solar-induced chlorophyll fluorescence that correlates with canopy photosynthesis on diurnal and seasonal scales in a temperate deciduous forest. Geophysical Research Letters 42:2977-2987.