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Published April 2020 | public
Journal Article Metadata-only

The potential of satellite FPAR product for GPP estimation: An indirect evaluation using solar-induced chlorophyll fluorescence

Zhang, Zhaoying
Zhang, Yongguang
Zhang, Yao ORCID icon
Gobron, Nadine
Frankenberg, Christian ORCID icon
Wang, Songhan
Li, Zhaohui

Abstract

Satellite remotely sensed fraction of photosynthetically active radiation (FPAR) products are widely used in land-surface monitoring and modeling, especially for estimating global terrestrial photosynthetic activity through light use efficiency (LUE) models. PAR absorbed by active chlorophyll (APAR_(chl)) is directly linked to vegetation photosynthesis and can be used to estimate ecosystem gross primary production (GPP). Previous studies have demonstrated that solar induced chlorophyll fluorescence has very tight relationship with APAR_(chl) at various ecosystems. Therefore, the solar angle normalized SIF (nSIF) is directly related to the fraction of PAR absorbed by chlorophyll (FPAR_(chl)). This paper intercompared six space FPAR products from Moderate Resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), Copernicus Global Land Service (CGLS), Multi-angle Imaging SpectroRadiometer (MISR), Earth Polychromatic Imaging Camera (EPIC) and Ocean and Land Colour Instrument (OLCI). Their potential relationships with FPAR_(chl) were indirectly evaluated with both spaceborne (Orbiting Carbon Observatory-2, OCO-2 and TROPOspheric Monitoring Instrument, TROPOMI) and airborne (Chlorophyll Fluorescence Imaging Spectrometer, CFIS) nSIF data as well as in situ GPP measurements. Our results show that these FPAR products are different in terms of amplitudes and seasonal variations across biomes. Among six FPAR products, OLCI FPAR shows the best relationships with TROPOMI nSIF740, OCO-2 nSIF757, and CFIS nSIF755. The coefficient of determination (R²) for the relationship between OLCI FPAR and TROPOMI nSIF740 is 0.79 ± 0.17 on a global average. APAR calculated from OLCI also exhibits the best relationship (R² = 0.79) with in situ GPP over 25 flux towers.

Additional Information

© 2020 Elsevier Inc. Received 17 June 2019, Revised 22 January 2020, Accepted 24 January 2020, Available online 31 January 2020. This research was financially supported by the National Key Research and Development Program of China (2019YFA0606601), International Cooperation and Exchange Programs between NSFC and DFG (41761134082) and General Program of National Science Foundation of China (41671421). This research was also supported by the Innovative and Practical Program of Graduate Student in Jiangsu Province (SJKY190037). The authors are thankful to the science team members who produce and manage MODIS, VIIRS, GEOV2, EPIC, MISR, OLCI, OCO-2, TROPOMI, CFIS and Landsat 8 data. This work used eddy covariance data acquired and shared by the AmeriFlux community. We thank the investigators who provided flux tower data publicly available. We also thank Dr. Yuri Knyazikhin for his insightful comments and suggestions on this study. We would like to thank Prof. Christiaan van der Tol for making the SCOPE model (v1.73) publicly available. We are grateful to three anonymous reviewers for their suggestions and comments, which significantly improved the quality of this paper. CRediT authorship contribution statement: Zhaoying Zhang: Conceptualization, Methodology, Software, Formal analysis, Writing - original draft, Writing - review & editing. Yongguang Zhang: Conceptualization, Formal analysis, Writing - original draft, Writing - review & editing, Funding acquisition. Yao Zhang: Methodology, Formal analysis, Writing - original draft, Writing - review & editing. Nadine Gobron: Formal analysis, Writing - review & editing. Christian Frankenberg: Resources. Songhan Wang: Writing - original draft. Zhaohui Li: Writing - original draft. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional details

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August 22, 2023
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