Articles | Volume 6, issue 8
Biogeosciences, 6, 1655–1670, 2009

Special issue: The ACCENT-VOCBAS field campaign on biosphere-atmosphere interactions...

Biogeosciences, 6, 1655–1670, 2009

  14 Aug 2009

14 Aug 2009

Concentrations and fluxes of biogenic volatile organic compounds above a Mediterranean macchia ecosystem in western Italy

B. Davison1, R. Taipale2, B. Langford1, P. Misztal3,4, S. Fares5,*, G. Matteucci5, F. Loreto5, J. N. Cape3, J. Rinne2, and C. N. Hewitt1 B. Davison et al.
  • 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
  • 2University of Helsinki, Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
  • 3Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
  • 4School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, UK
  • 5National Research Council, Institute of Agro-environmental and Forest Biology, Via Salaria km. 29300, 00016 Monterotondo Scalo, Rome, Italy
  • *now at: University of California, Department of Environmental Science, Policy, and Management, 137 Mulford Hall, Berkeley, CA 94720, USA

Abstract. Emission rates and concentrations of biogenic volatile organic compounds (BVOCs) were measured at a Mediterranean coastal site at Castelporziano, approximately 25 km south-west of Rome, between 7 May and 3 June 2007, as part of the ACCENT-VOCBAS field campaign on biosphere–atmosphere interactions. Concentrations and emission rates were measured using the disjunct eddy covariance (DEC) method utilizing three different proton transfer reaction mass spectrometers (PTR-MS) so allowing a comparison between the instruments. The high resolution data from the PTR-MS instruments considerably enhances the original BEMA measurements of the mid 1990s.

Depending on the measurement period, the volume mixing ratios were in the range 1.6–3.5 ppbv for methanol, 0.44–1.3 ppbv for acetaldehyde, 0.96–2.1 ppbv for acetone, 0.10–0.14 ppbv for isoprene, and 0.13–0.30 ppbv for monoterpenes. A diurnal cycle in mixing ratios was apparent with daytime maxima for methanol, acetaldehyde, acetone, and isoprene. The fluxes ranged from 370–440 μg m−2 h−1 for methanol, 180–360 μg m−2 h−1 for acetaldehyde, 180–450 μg m−2 h−1 for acetone, 71–290 μg m−2 h−1 for isoprene, and 240–860 μg m−2 h−1 for monoterpenes. From the measured flux data (7 May–3 June) an average basal emission rate for the Macchia vegetation was calculated of 430 μg m−2 h−1 for isoprene and 1100 μg m−2 h−1 for monoterpenes.

Final-revised paper