TY - JOUR

T1 - Ground-level ozone influenced by circadian control of isoprene emissions

AU - Hewitt, C. N.

AU - Ashworth, K.

AU - Boynard, A.

AU - Guenther, A.

AU - Langford, B.

AU - MacKenzie, A. R.

AU - Misztal, P. K.

AU - Nemitz, E.

AU - Owen, S. M.

AU - Possell, M.

AU - Pugh, T. A. M.

AU - Ryan, A. C.

AU - Wild, O.

PY - 2011/10

Y1 - 2011/10

N2 - The volatile organic compound isoprene is produced by many plant species, and provides protection against biotic and abiotic stresses. Globally, isoprene emissions from plants are estimated to far exceed anthropogenic emissions of volatile organic compounds. Once in the atmosphere, isoprene reacts rapidly with hydroxyl radicals to form peroxy radicals, which can react with nitrogen oxides to form ground-level ozone. Here, we use canopy-scale measurements of isoprene fluxes from two tropical ecosystems in Malaysia - a rainforest and an oil palm plantation - and three models of atmospheric chemistry to explore the effects of isoprene fluxes on ground-level ozone. We show that isoprene emissions in these ecosystems are under circadian control on the canopy scale, particularly in the oil palm plantation. As a result, these ecosystems emit less isoprene than present emissions models predict. Using local-, regional- and global-scale models of atmospheric chemistry and transport, we show that accounting for circadian control of isoprene emissions brings model predictions of ground-level ozone into better agreement with measurements, especially in isoprene-sensitive regions of the world.

AB - The volatile organic compound isoprene is produced by many plant species, and provides protection against biotic and abiotic stresses. Globally, isoprene emissions from plants are estimated to far exceed anthropogenic emissions of volatile organic compounds. Once in the atmosphere, isoprene reacts rapidly with hydroxyl radicals to form peroxy radicals, which can react with nitrogen oxides to form ground-level ozone. Here, we use canopy-scale measurements of isoprene fluxes from two tropical ecosystems in Malaysia - a rainforest and an oil palm plantation - and three models of atmospheric chemistry to explore the effects of isoprene fluxes on ground-level ozone. We show that isoprene emissions in these ecosystems are under circadian control on the canopy scale, particularly in the oil palm plantation. As a result, these ecosystems emit less isoprene than present emissions models predict. Using local-, regional- and global-scale models of atmospheric chemistry and transport, we show that accounting for circadian control of isoprene emissions brings model predictions of ground-level ozone into better agreement with measurements, especially in isoprene-sensitive regions of the world.

KW - TROPICAL RAIN-FOREST

KW - VOLATILE ORGANIC-COMPOUNDS

KW - MODEL

KW - CHEMISTRY

KW - HYDROCARBONS

KW - FLUXES

KW - URBAN

UR - http://www.scopus.com/inward/record.url?scp=80053487770&partnerID=8YFLogxK

U2 - 10.1038/NGEO1271

DO - 10.1038/NGEO1271

M3 - Journal article

VL - 4

SP - 671

EP - 674

JO - Nature Geoscience

JF - Nature Geoscience

SN - 1752-0894

IS - 10

ER -