Filling-in of near-infrared solar lines by terrestrial fluorescence and other geophysical effects: simulations and space-based observations from SCIAMACHY and GOSAT

By Joanna Joiner, Y. Yoshida, A. Vasilkov, E. Middleton, P. Campbell, A. Kuze, L. Corp. 2012

178 citations recorded by the source corpus.

Abstract. Global mapping of terrestrial vegetation fluorescence from space has recently been accomplished with high spectral resolution (ν/Δν > 35 000) measurements from the Japanese Greenhouse gases Observing SATellite (GOSAT). These data are of interest because they can potentially provide global information on the functional status of vegetation including light-use efficiency and global primary productivity that can be used for global carbon cycle modeling. Quantifying the impact of fluorescence on the O2-A band is important as this band is used for photon pathlength characterization in cloud- and aerosol-contaminated pixels for trace-gas retrievals including CO2. Here, we examine whether fluorescence information can be derived from space using potentially lower-cost hyperspectral instrumentation, i.e., more than an order of magnitude less spectral resolution (ν/Δν ~ 1600) than GOSAT, with a relatively simple algorithm. We discuss laboratory measurements of fluorescence near one of the few wide and deep solar Fraunhofer lines in the long-wave tail of the fluorescence emission region, the calcium (Ca) II line at 866 nm that is observable with a spectral resolution of ~0.5 nm. The filling-in of the Ca II line due to additive signals from various atmospheric and terrestrial effects, including fluorescence, is simulated. We then examine filling-in of this line using the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) satellite instrument. In order to interpret the satellite measurements, we developed a general approach to correct for various instrumental artifacts that produce false filling-in of solar lines in satellite measurements. The approach is applied to SCIAMACHY at the 866 nm Ca II line and to GOSAT at 758 and 770 nm on the shoulders of the O2-A feature where there are several strong solar Fraunhofer lines that are filled in primarily by vegetation fluorescence. Finally, we compare temporal and spatial variations of SCIAMACHY additive signals with those of GOSAT and the Enhanced Vegetation Index (EVI) from the MODerate-resolution Imaging Spectroradiometer (MODIS). Although the derived additive signals from SCIAMACHY are extremely weak at 866 nm, their spatial and temporal variations are consistent with chlorophyll a fluorescence or another vegetation-related source. We also show that filling-in occurs at 866 nm over some barren areas, possibly originating from luminescent minerals in rock and soil.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/480f923b5beb00ca3b3bd333a9088d80cdfc8e28

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Citations in the corpus

The FLuorescence EXplorer Mission Concept—ESA’s Earth Explorer 8 (2017, background): “They include GOSAT (TANSO-FTS sensor), MetOp (GOME-2), and Envisat (SCIAMACHY and MERIS) (see [5], [6]).”
Using field spectroscopy to assess the potential of statistical approaches for the retrieval of sun-induced chlorophyll fluorescence from ground and space (2013, methodology): “The same in-filling principle was later used by Joiner et al. (2012) for global Fs retrievals fromSCIAMACHY (SCanning ImagingAbsorption spectroMeter for Atmospheric CHartographY) measurements in the strong Fraunhofer line in 866 nm.”
Coupling between the terrestrial carbon and water cycles—a review (2019, methodology): “A global remote sensing of solarinduced chlorophyll fluorescence (SIF) has become widely available from satellites such as GOSAT, GOME-2, SCIAMACHY and OCO-2 (Frankenberg et al 2011a, 2011b, Joiner et al 2011a, 2012, 2013, Guanter et al 2012).”