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| Titel |
BVOC fluxes from oil palm canopies in South East Asia |
| VerfasserIn |
P. K. Misztal, J. N. Cape, B. Langford, E. Nemitz, C. Helfter, S. Owen, M. R. Heal, C. N. Hewitt, D. Fowler |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029906
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| Zusammenfassung |
| Fluxes by virtual disjunct eddy covariance were measured for the first time in South-East
Asia in 2008 from an oil palm plantation. Malaysia and Indonesia account for more than 80%
of world oil palm production. Our in situ findings suggest much higher isoprene
emissions from oil palms than from rainforest, which is consistent with earlier
lab-based predictions of emissions from oil palms (Wilkinson et al., 2006). 50% of
global biogenic VOC emissions are estimated to derive from tropical rainforests
(Guenther et al., 1995) although in fact a large portion of the emission may derive
from oil palms in the tropics. Isoprene and monoterpenes are regarded as the most
important biogenic VOCs for the atmospheric chemistry. Overall, maximum isoprene
emissions from oil palms were recorded at 11:00 local time, with a mean value of 13
mg m-2 h-1. At the rainforest, the maximum fluxes of isoprene were observed
later in the day, at about 13:00 with an average of 2.5 mg m-2 h-1. Initial flux
results for total monoterpenes indicate that their mass emission ratio with respect to
isoprene was about 1:9 at the rainforest and 1:18 at the oil palm plantation. The
results are presented with reference to temperature, photosynthetic radiation and
meteorological drivers as well as in comparison with CO2 and H2O fluxes. Empirical
parameters in the Guenther algorithm for MEGAN (Guenther et al, 2006), which was
originally designed for the Amazon region, have been optimised for this oil palm
study. The emission factor obtained from eddy covariance measurements was 18.8
mg m-2 h-1, while the one obtained from leaf level studies at the site was 19.5
mg m-2 h-1. Isoprene fluxes from both Amazonia (Karl et al., 2007) and from
rainforest in Borneo 2008 seem to be much lower than from oil palms. This can have
consequences for atmospheric chemistry of land use change from rainforest to oil palm
plantation, including formation of ozone, SOA and particles and indirect effects on
the removal rate of greenhouse gases and pollutants by decreasing OH budgets.
Global models predicting atmospheric changes and bottom-up estimates from the
tropics must be constrained by direct measurements such as presented here, taking
separate account of these major contributions from oil palm plantations and tropical
rainforests.
References:
Guenther, A., C.N. Hewitt, D. Erickson, R. Fall, C. Geron, T.E. Graedel, P. Harley, L.
Klinger, M. Lerdau, W.A. McKay, T. Pierce, B. Scholes, R. Steinbrecher, R. Tallamraju, J.
Taylor and P. Zimmerman, 1995: A global model of natural volatile organic compound
emissions. Journal of Geophysical Research 100, 8873–8892.
Guenther, A., T. Karl, P. Harley, C. Wiedinmyer, P. I. Palmer, and C. Geron,
2006: Estimates of global terrestrial isoprene emissions using MEGAN (Model of
Emissions of Gases and Aerosols from Nature). Atmos. Chem. Phys. Discuss., 6,
107-173.
Karl, T., A. Guenther, R. J. Yokelson, J. Greenberg, M. Potosnak, D. R. Blake, and P.
Artaxo, 2007: The tropical forest and fire emissions experiment: Emission, chemistry, and
transport of biogenic volatile organic compounds in the lower atmosphere over Amazonia.
Journal of Geophysical Research 112, D18302.
Wilkinson, M. J., S. M. Owen, M. Possell, J. Hartwell, P. Gould, A. Hall, C. Vickers, and
C. N. Hewitt, 2006: Circadian control of isoprene emissions from oil palm (Elaeis
guineensis). Plant Journal 47, 960-968. |
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