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| Titel |
Photosynthesis-dependent isoprene emission from leaf to planet in a global carbon-chemistry-climate model |
| VerfasserIn |
N. Unger, K. Harper, Y. Zheng, N. Y. Kiang, I. Aleinov, A. Arneth, G. Schurgers, C. Amelynck, A. Goldstein, A. Guenther, B. Heinesch, C. N. Hewitt, T. Karl, Q. Laffineur, B. Langford, K. A. McKinney, P. Misztal, M. Potosnak, J. Rinne, S. Pressley, N. Schoon, D. Serça |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 20 ; Nr. 13, no. 20 (2013-10-22), S.10243-10269 |
| Datensatznummer |
250085760
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| Publikation (Nr.) |
 copernicus.org/acp-13-10243-2013.pdf |
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| Zusammenfassung |
| We describe the implementation of a biochemical model of isoprene emission
that depends on the electron requirement for isoprene synthesis into the
Farquhar–Ball–Berry leaf model of photosynthesis and stomatal conductance
that is embedded within a global chemistry-climate simulation framework. The
isoprene production is calculated as a function of electron transport-limited
photosynthesis, intercellular and atmospheric carbon dioxide concentration, and canopy
temperature. The vegetation biophysics module computes the photosynthetic
uptake of carbon dioxide coupled with the transpiration of water vapor and
the isoprene emission rate at the 30 min physical integration time step of
the global chemistry-climate model. In the model, the rate of carbon
assimilation provides the dominant control on isoprene emission variability
over canopy temperature. A control simulation representative of the present-day
climatic state that uses 8 plant functional types (PFTs), prescribed
phenology and generic PFT-specific isoprene emission potentials (fraction of
electrons available for isoprene synthesis) reproduces 50% of the
variability across different ecosystems and seasons in a global database of
28 measured campaign-average fluxes. Compared to time-varying isoprene flux
measurements at 9 select sites, the model authentically captures the observed
variability in the 30 min average diurnal cycle (R2 = 64–96%)
and simulates the flux magnitude to within a factor of 2. The control run
yields a global isoprene source strength of 451 TgC yr−1 that
increases by 30% in the artificial absence of plant water stress and by
55% for potential natural vegetation. |
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