nerc.ac.uk

Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy

Acton, W. Joe. F; Schallhart, Simon ; Langford, Ben; Valach, Amy; Rantala, Pekka; Fares, Silvano ; Carriero, Giulia ; Tillmann, Ralf ; Tomlinson, Sam J.; Dragosits, Ulrike; Gianelle, Damiano ; Hewitt, C. Nicholas ; Nemitz, Eiko. 2016 Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy. Atmospheric Chemistry and Physics, 16 (11). 7149-7170. 10.5194/acp-16-7149-2016

Before downloading, please read NORA policies.
[img]
Preview
Text
N513801JA.pdf - Published Version
Available under License Creative Commons Attribution.

Download (4MB) | Preview

Abstract/Summary

This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs) 4 m above a mixed oak and hornbeam forest in northern Italy. Fluxes of methanol, acetaldehyde, isoprene, methyl vinyl ketone + methacrolein, methyl ethyl ketone and monoterpenes were obtained using both a proton-transfer-reaction mass spectrometer (PTR-MS) and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) together with the methods of virtual disjunct eddy covariance (using PTR-MS) and eddy covariance (using PTR-ToF-MS). Isoprene was the dominant emitted compound with a mean daytime flux of 1.9 mg m−2 h−1. Mixing ratios, recorded 4 m above the canopy, were dominated by methanol with a mean value of 6.2 ppbv over the 28-day measurement period. Comparison of isoprene fluxes calculated using the PTR-MS and PTR-ToF-MS showed very good agreement while comparison of the monoterpene fluxes suggested a slight over estimation of the flux by the PTR-MS. A basal isoprene emission rate for the forest of 1.7 mg m−2 h−1 was calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) isoprene emission algorithms (Guenther et al., 2006). A detailed tree-species distribution map for the site enabled the leaf-level emission of isoprene and monoterpenes recorded using gas-chromatography mass spectrometry (GC–MS) to be scaled up to produce a bottom-up canopy-scale flux. This was compared with the top-down canopy-scale flux obtained by measurements. For monoterpenes, the two estimates were closely correlated and this correlation improved when the plant-species composition in the individual flux footprint was taken into account. However, the bottom-up approach significantly underestimated the isoprene flux, compared with the top-down measurements, suggesting that the leaf-level measurements were not representative of actual emission rates.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.5194/acp-16-7149-2016
CEH Sections: Dise
ISSN: 1680-7316
Additional Information. Not used in RCUK Gateway to Research.: Open Access paper - full text available via Official URL link.
NORA Subject Terms: Atmospheric Sciences
Date made live: 13 Jun 2016 14:13 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/513801

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...