Bidirectional ammonia exchange above a mixed coniferous forest

Johan Neirynck, R Ceulemans

    Onderzoeksoutput: Bijdrage aan tijdschriftA1: Web of Science-artikel

    Uittreksel

    Two canopy compensation point models were used to study the bidirectional exchange of ammonia over a mixed coniferous forest subjected to high nitrogen deposition. The models were tested for 16 time series, average fluxes of which ranged between -270 and +1 ngm-2s-1. The static model consisted of a bidirectional stomatal flux and a unidirectional cuticular flux component. The dynamic model also allowed for desorption of ammonia from the leaf surface and took into account ammonia fluxes from precedent periods. The apoplastic ammonium/hydrogen ion ratio (Γ), which was derived to estimate the stomatal compensation point (Χs), amounted to 3300 in spring and 1375 during the summer/autumn. Empirical descriptions for cuticular resistances (Rw) in the static model, developed as a function of micrometeorological conditions and codeposition effects, failed to reproduce the measured fluxes. A better match with measurements was obtained using the dynamic model, which succeeded in simulating net-emission during the daytime.

    TaalEngels
    TijdschriftEnvironmental Pollution
    Volume154
    Exemplaarnummer3
    Pagina's (van-tot)424-438
    Aantal pagina's15
    DOI's
    StatusGepubliceerd - 2008

    Thematische lijst

    • Milieu

    EWI Biomedische wetenschappen

    • B002-biofysica

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