Simulated effects of changes in direct and diffuse radiation on canopy scale isoprene emissions from vegetation following volcanic eruptions

Wilton, D. J. and Hewitt, C. N. and Beerling, D. J. (2011) Simulated effects of changes in direct and diffuse radiation on canopy scale isoprene emissions from vegetation following volcanic eruptions. Atmospheric Chemistry and Physics, 11 (22). pp. 11723-11731. ISSN 1680-7316

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Abstract

Volcanic eruptions can alter the quality of incoming solar irradiance reaching the Earth's surface thereby influencing the interactions between vegetation and the Earth system. Isoprene (C5H8) is a biogenic volatile organic compound emitted from leaves at a rate that is strongly dependent on the received flux of photosynthetically active radiation (PAR). We used a theoretical approach to investigate the potential for volcanic eruptions to change the isoprene flux from terrestrial forests using canopy-scale isoprene emission simulations that vary either the relative or absolute amount of diffuse (Idiff) and direct (Idir) PAR. According to our simulations for a northern hardwood deciduous forest, if the total amount of PAR during summer remains constant while the proportion of Idiff increases, canopy-scale isoprene emissions increase. This effect increases as leaf area index (LAI) increases. Simulating a decrease in the total amount of PAR, and a corresponding increase in Idiff fraction, as measured during the 1992 Pinatubo eruption, changes daily total canopy-scale isoprene emissions from terrestrial vegetation in summertime by +2.8% and ĝ̂'1.4% for LAI of 6 and 2, respectively. These effects have not previously been realized or quantified. Better capturing the effects of volcanic eruptions (and other major perturbations to the atmospheric aerosol content) on isoprene emissions from the terrestrial biosphere, and hence on the chemistry of the atmosphere, therefore may require inclusion of the effects of aerosols they produce on climate and the quality of PAR.

Item Type:
Journal Article
Journal or Publication Title:
Atmospheric Chemistry and Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1902
Subjects:
ID Code:
138124
Deposited By:
Deposited On:
22 Oct 2019 14:45
Refereed?:
Yes
Published?:
Published
Last Modified:
01 Jan 2020 12:18