TROPOMI observations allow for robust exploration of the relationship between solar-induced chlorophyll fluorescence and terrestrial gross primary production

Journal Article · Tue Nov 02 00:00:00 EDT 2021 · Remote Sensing of Environment

DOI:https://doi.org/10.1016/j.rse.2021.112748· OSTI ID:1981743

Li, Xing ^[1]; Xiao, Jingfeng ^[2]

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1. Seoul National University (South Korea); University of New Hampshire, Durham, NH (United States)
2. University of New Hampshire, Durham, NH (United States)

Solar-induced chlorophyll fluorescence (SIF) observed by satellites has advanced the monitoring of terrestrial photosynthesis regionally and globally. The relationship between SIF and gross primary production (GPP) at leaf, canopy, and ecosystem scales has received tremendous attention in recent years. It remains controversial whether the SIF-GPP relationship at the ecosystem scale is universal or dependent upon vegetation type. New SIF observations from the TROPOspheric Monitoring Instrument (TROPOMI) with unprecedented high spatial and temporal resolution provide a new opportunity to elucidate the SIF-GPP relationship. Here, we examine the SIF-GPP relationship for seven major vegetation types across the U.S. with TROPOMI SIF and in-situ GPP data for 83 eddy covariance flux sites. We find that TROPOMI SIF shows a strong and consistent relationship with tower-based GPP at both satellite footprint and grid-cell levels. The slope of the SIF-GPP relationship is similar among all the vegetation types except croplands, demonstrating a nearly universal (converging to ~13.5 g C m^-2 d^-1/W m^-2 μm^-1 sr^-1) rather than vegetation type-specific SIF-GPP relationship. This confirms that TROPOMI SIF can be used as a proxy for GPP across a wide variety of vegetation types and can also be used to quantify GPP by avoiding uncertainty associated with land cover maps. The C₄ crops have a much higher slope than the C₃ crops, and therefore croplands tend to have a higher slope than C₃-dominated vegetation types (e.g., forests, shrublands, savannas). We also find that the TROPOMI SIF is well correlated with GPP under normal or wetter conditions, while their relationship becomes weaker under water stress. In conclusion, our TROPOMI-based study could improve our understanding of the SIF-GPP relationship at the ecosystem scale and advance the mapping of GPP globally with SIF observations from space.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). AmeriFlux
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: AC02-05CH11231; DEB-2017870; NNX16AG61G
• OSTI ID: 1981743
• Alternate ID(s): OSTI ID: 1828824
• Journal Information: Remote Sensing of Environment, Vol. 268, Issue C; ISSN 0034-4257
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Environmental Sciences & Ecology
Remote Sensing
Imaging Science & Photographic Technology
Carbon cycle
Sun-induced fluorescence
Gross primary productivity
Eddy covariance
Photosynthesis
Photosynthetic pathway
Water stress
Spatial and temporal integration
Climate change
AmeriFlux