title: The exchange of nitric oxide, nitrogen dioxide and ozone between pasture and the atmosphere.
abstract: Fluxes of NO, NO2 and O3 were determined over a drained marshland pasture in south-east England by using flux-gradient techniques. Nitric oxide was found to be emitted at rates of up to 40 ng m(-2) s(-1), the rate of emission being related to the magnitude of the eddy diffusivity. Nitrogen dioxide deposited at rates of up to 90 ng m(-2) s(-1) under the control of stomatal resistance, a clear diurnal cycle being observed. Minimum canopy resistance was of the order of 80 s m(-1). Ozone deposition was also controlled by stomatal resistance, the minimum canopy resistance being around 100 s m(-1) and fluxes reaching a maximum of 220 ng m(-2) s(-1). Corrections made to NO and NO2 fluxes to compensate for chemical reactions showed flux divergences of the order of 30% for NO and NO2, but these were not statistically significantly different from the measured fluxes. The pasture was found to be a net sink for nitrogen in the form of NOx.
authors.affiliation: Institute of Terrestrial Ecology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK.
authors.forename: K J
authors.initials: KJ
authors.lastname: Hargreaves
authors.forename: D
authors.initials: D
authors.lastname: Fowler
authors.forename: R L
authors.initials: RL
authors.lastname: Storeton-West
authors.forename: J H
authors.initials: JH
authors.lastname: Duyzer