edu.ucar.opensky::articles:13076 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T03:38:28.202911 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d76d5twm Photosynthesis-dependent isoprene emission from leaf to planet in a global carbon-chemistry-climate model 2013-10-22T00:00:00Z publication https://n2t.org/ark:/85065/d76d5twm https://doi.org/10.5194/acp-13-10243-2013 Unger, N. author Harper, K. author Zheng, Y. author Kiang, N. author Aleinov, I. author Arneth, A. author Schurgers, G. author Amelynck, C. author Goldstein, A. author Guenther, Alex B. author Heinesch, B. author Hewitt, N. author Karl, T. author Laffineur, Q. author Langford, B. author McKinney, K. author Misztal, P. author Potosnak, M. author Rinne, J. author Pressley, S. author Schoon, N. author Serça, D. author UCAR/NCAR - Library publisher 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. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2013. This work is distributed under the Creative Commons Attribution 3.0 License. None eng geoscientificInformation