Premium
Disentangling chlorophyll fluorescence from atmospheric scattering effects in O 2 A‐band spectra of reflected sun‐light
Author(s) -
Frankenberg C.,
Butz A.,
Toon G. C.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045896
Subject(s) - spectral line , scattering , diffuse sky radiation , physics , fluorescence , chlorophyll fluorescence , spectral bands , chlorophyll , astrophysics , atmospheric sciences , remote sensing , optics , environmental science , astronomy , geology , chemistry , organic chemistry
Global retrieval of solar induced fluorescence emitted by terrestrial vegetation can provide an unprecedented measure for photosynthetic efficiency. The GOSAT (JAXA, launched Feb. 2009) and OCO‐2 (NASA, to be launched 2013) satellites record high‐resolution spectra in the O 2 A‐band region, overlapping part of the chlorophyll fluorescence spectrum. We show that fluorescence cannot be unambiguously discriminated from atmospheric scattering effects using O 2 absorption lines. This can cause systematic biases in retrieved scattering parameters (aerosol optical thickness, aerosol height, surface pressure, surface albedo) if fluorescence is neglected. Hence, we demonstrate an efficient alternative fluorescence least‐squares retrieval method based solely on strong Fraunhofer lines in the vicinity of the O 2 A‐band, disentangling fluorescence from scattering effects. Not only does the Fraunhofer line fit produce a more accurate estimate of fluorescence emission, but it also allows improved retrievals of atmospheric aerosols from the O 2 A‐band.