Strong constraint on modelled global carbon uptake using solar-induced chlorophyll fluorescence data
Abstract
Accurate terrestrial biosphere model (TBM) simulations of gross carbon uptake (gross primary productivity – GPP) are essential for reliable future terrestrial carbon sink projections. However, uncertainties in TBM GPP estimates remain. Newly-available satellite-derived sun-induced chlorophyll fluorescence (SIF) data offer a promising direction for addressing this issue by constraining regional-to-global scale modelled GPP. Here, we use monthly 0.5° GOME-2 SIF data from 2007 to 2011 to optimise GPP parameters of the ORCHIDEE TBM. The optimisation reduces GPP magnitude across all vegetation types except C4 plants. Global mean annual GPP therefore decreases from 194 ± 57 PgCyr^(−1) to 166 ± 10 PgCyr^(−1), bringing the model more in line with an up-scaled flux tower estimate of 133 PgCyr^(−1). Strongest reductions in GPP are seen in boreal forests: the result is a shift in global GPP distribution, with a ~50% increase in the tropical to boreal productivity ratio. The optimisation resulted in a greater reduction in GPP than similar ORCHIDEE parameter optimisation studies using satellite-derived NDVI from MODIS and eddy covariance measurements of net CO_2 fluxes from the FLUXNET network. Our study shows that SIF data will be instrumental in constraining TBM GPP estimates, with a consequent improvement in global carbon cycle projections.
Additional Information
© 2018 The Authors. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received: 07 November 2017; Accepted: 08 January 2018; Published online: 31 January 2018. This work was supported and co-funded by the ESA FLEX-Bridge Project (http://www.flex-photosyn.ca/FB_HOME.htm), the Copernicus Atmosphere Monitoring Service (CAMS41 project) implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission, and the CNES TOSCA Flu-OR Project. LG and PK were funded by the Emmy Noether Programme of the German Research Foundation (GU 1276/1-1). Author Contributions: N.M. instigated and designed the study in discussion with F.M., P.L., P.P., and C.B. N.M. conducted all model simulations, assimilation runs, and posterior analyses, with support from C.B. on the assimilation system and calculation of the posterior covariance matrix. L.G. and P.K. provided the SIF data and provided details, guidance and comments on characteristics and proper use of the data. N.M. discussed technical details of assimilation set-up and initial interpretation of results with P.L., P.P., C.B., F.M. and J.G.D. N.M. drafted the manuscript. All authors provided detailed comments on the manuscript draft, including further interpretation of the results. The authors declare that they have no competing interests.Errata
In this Article, reference 23 is incorrectly cited in its third instance. The correct reference appears below as reference 1, and should appear in the Introduction as below: "Meanwhile, several modelling groups have used SIF data to optimise fluorescence model parameters" should read: "Meanwhile, several modelling groups have used SIF data to optimise fluorescence model parameters"Attached Files
Published - s41598-018-20024-w.pdf
Supplemental Material - 41598_2018_20024_MOESM1_ESM.pdf
Erratum - s41598-018-28697-z.pdf
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Additional details
- PMCID
- PMC5792553
- Eprint ID
- 84672
- Resolver ID
- CaltechAUTHORS:20180205-095242589
- European Space Agency (ESA)
- CAMS41
- Copernicus Atmosphere Monitoring Service
- European Commission
- Centre National d'Études Spatiales (CNES)
- GU 1276/1-1
- Deutsche Forschungsgemeinschaft (DFG)
- Created
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2018-02-05Created from EPrint's datestamp field
- Updated
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2023-06-01Created from EPrint's last_modified field