Underestimation of global photosynthesis in Earth System Models due to representation of vegetation structure

Braghiere, R. K., Quaife, T. ORCID: https://orcid.org/0000-0001-6896-4613, Black, E. ORCID: https://orcid.org/0000-0003-1344-6186, He, L. and Chen, J. M. (2019) Underestimation of global photosynthesis in Earth System Models due to representation of vegetation structure. Global Biogeochemical Cycles, 33 (11). pp. 1358-1369. ISSN 1944-9224 doi: 10.1029/2018GB006135

Abstract/Summary

The impact of vegetation structure on the absorption of shortwave radiation in Earth System Models (ESMs) is potentially important for accurate modelling of the carbon cycle and hence climate projections. A proportion of incident shortwave radiation is used by plants to photosynthesize and canopy structure has a direct impact on the fraction of this radiation which is absorbed. This paper evaluates how modelled carbon assimilation of the terrestrial biosphere is impacted when clumping derived from satellite data is incorporated. We evaluated impacts of clumping on photosynthesis using the Joint UK Land Environment Simulator, the land surface scheme of the UK Earth System Model. At the global level, Gross Primary Productivity (GPP) increased by 5.53 ± 1.02 PgC yr−1 with the strongest absolute increase in the tropics. This is contrary to previous studies that have shown a decrease in photosynthesis when similar clumping data sets have been used to modify light interception in models. In our study additional transmission of light through upper canopy layers leads to enhanced absorption in lower layers in which photosynthesis tends to be light limited. We show that this result is related to the complexity of canopy scheme being used.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/86393
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > National Centre for Earth Observation (NCEO) Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Uncontrolled Keywords	Atmospheric Science, Global and Planetary Change, General Environmental Science, Environmental Chemistry.
Publisher	American Geophysical Union
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