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Marko Scholze

Senior lecturer

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Estimating global gross primary productivity using chlorophyll fluorescence and a data assimilation system with the BETHY-SCOPE model

Author

  • Alexander J. Norton
  • Peter J. Rayner
  • Ernest N. Koffi
  • Marko Scholze
  • Jeremy D. Silver
  • Ying Ping Wang

Summary, in English

This paper presents the assimilation of solar-induced chlorophyll fluorescence (SIF) into a terrestrial biosphere model to estimate the gross uptake of carbon through photosynthesis (GPP). We use the BETHY-SCOPE model to simulate both GPP and SIF using a process-based formulation, going beyond a simple linear scaling between the two. We then use satellite SIF data from the Orbiting Carbon Observatory-2 (OCO-2) for 2015 in the data assimilation system to constrain model biophysical parameters and GPP. The assimilation results in considerable improvement in the fit between model and observed SIF, despite a limited capability to fit regions with large seasonal variability in SIF. The SIF assimilation increases global GPP by 31% to 167±5 PgCyr-1 and shows an improvement in the global distribution of productivity relative to independent estimates, but a large difference in magnitude. This change in global GPP is driven by an overall increase in photosynthetic lightuse efficiency across almost all biomes and more minor, regionally distinct changes in APAR. This process-based data assimilation opens up new pathways to the effective utilization of satellite SIF data to improve our understanding of the global carbon cycle.

Department/s

  • Dept of Physical Geography and Ecosystem Science
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • eSSENCE: The e-Science Collaboration
  • MERGE: ModElling the Regional and Global Earth system

Publishing year

2019-08-13

Language

English

Pages

3069-3093

Publication/Series

Biogeosciences

Volume

16

Issue

15

Document type

Journal article

Publisher

Copernicus GmbH

Topic

  • Physical Geography

Status

Published

ISBN/ISSN/Other

  • ISSN: 1726-4170