Estimation of solar-induced vegetation fluorescence from space measurements

• Published in: Geophysical research letters Vol. 34; no. 8; pp. L08401 - n/a
• Main Authors: Guanter, L., Alonso, L., Gómez-Chova, L., Amorós-López, J., Vila, J., Moreno, J.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01.04.2007; Blackwell Publishing Ltd
• Subjects: Biogeosciences; Carbon cycling; Earth sciences; Earth, ocean, space; Exact sciences and technology; Instruments and techniques; Remote sensing; vegetation fluorescence; remote sensing; vegetation fluorescence; satellites; Validation; fluorescence; Absorption band; chlorophyll; solar radiation; vegetation; Excitation; correlation coefficient; Reflectance; radiance
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2007GL029289

A characteristic spectral emission is observed in vegetation chlorophyll under excitation by solar radiation. This emission, known as solar‐induced chlorophyll fluorescence, occurs in the red and near infra‐red spectral regions. In this paper a new methodology for the estimation of solar‐induced chlorophyll fluorescence from spaceborne and airborne sensors is presented. The fluorescence signal is included in an atmospheric radiative transfer scheme so that chlorophyll fluorescence and surface reflectance are retrieved consistently from the measured at‐sensor radiance. This methodology is tested on images acquired by the Medium Resolution Imaging Spectrometer (MERIS) on board the ENVIronmental SATellite (ENVISAT) taking advantage of its good characterization of the O2‐A absorption band. Validation of MERIS‐derived fluorescence is carried out by applying the method to data acquired by the Compact Airborne Spectrographic Imager (CASI‐1500) sensor concurrently to MERIS acquisitions. CASI‐derived fluorescence is in turn compared with ground‐based fluorescence measurements, a correlation coefficient R2 of 0.85 being obtained.