TY  - JOUR
AU  - Acton, W. Joe F.
AU  - Schallhart, Simon
AU  - Langford, Ben
AU  - Valach, Amy
AU  - Rantala, Pekka
AU  - Fares, Silvano
AU  - Carriero, Giulia
AU  - Tillmann, Ralf
AU  - Tomlinson, Sam J.
AU  - Dragosits, Ulrike
AU  - Gianelle, Damiano
AU  - Hewitt, C. Nicholas
AU  - Nemitz, Eiko
TI  - Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy
JO  - Atmospheric chemistry and physics
VL  - 16
IS  - 11
SN  - 1680-7324
CY  - Katlenburg-Lindau
PB  - EGU
M1  - FZJ-2016-03691
SP  - 7149 - 7170
PY  - 2016
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000378354600030
DO  - DOI:10.5194/acp-16-7149-2016
UR  - https://juser.fz-juelich.de/record/811182
ER  -