Das Projekt "Modellierung der Emission biogener, fluechtiger, organischer Verbindungen in der Kronenschicht europaeischer Waelder (VOCAMOD)" wird vom Umweltbundesamt gefördert und von Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung, Fraunhofer-Institut für Atmosphärische Umweltforschung durchgeführt. It is well known that biogenic volatile organic compounds (BVOC), especially chemically reactive compounds such as isoprene, monoterpenes and sesquiterpenes, are triggering tropospheric chemistry during the vegetation period. To derive effective control strategies for surface ozone in Europe, there is a pressing need to provide realistic BVOC emission scenarios for continental areas for estimating the contribution of BVOC to tropospheric chemistry and the potential changes in the emission behaviour due to climate and land use/land cover changes. On the basis of the work done within the CEC projects 'Biogenic Emissions in the Mediterranean Area' (BEMA) and 'Biogenic VOC Emissions and Photochemistry in the Boreal Regions of Europe' (BIPHOREP), a number of experiments are available adressing the BVOC emission from characteristic European forest ecosystems. The present project benefits from the existing data bases. It adresses the problem of the development and intercomparison of integrated canopy models to predict the emission of BVOCs and the effects of environmental controls (light, temperature etc) and chemistry. Improved canopy models at the patch scale are needed to provide useful input data to mesoscale models of tropospheric chemistry at adequate scales intime and space. Activities: Emission factors, emission algorithms, and future climate scenario. 1) To update emission factor and emission algorithms for European tree species with special emphasis on boreal and middle European vegetation. 2) To make the updated emission factors and emission algorithms for Picea abies, Pinus sylvestris and Quercus pubecens available for implementing in canopy models. 3) To make data available with respect of the influence of drought stress of the seasonal cycle of isoprene and aldehyde emission from Quercus pubescens. 4) To investigate and quantify the influence of elevated COdeep2 and elevated nitrogen input on the emission of isoprenoids from European Spruce/Beech canopies. BVOC chemistry module: 1) To define relevant chemistry degradation pathways for reactive BVOC, eg linalool. 2) To implement new mechanisms for BVOC in the 'Regional Atmospheric Chemistry Mechanism (RCAM). In the module the relevance of a chemical reaction for the canopy modelling is determined by the chemical time scale of the reaction in comparison to the residence time of trace gases inside the canopy. This residence time is determined by meteorological parameters inside the canopy, especially by the mean wind speed and the turbulence intensity. Canopy modelling: 1) To develop a parameterisation scheme for NOdeepx soil emissions from a Citrus plantation on the basis of field data from BEMA. 2) Co-ordinate the sensitivity and evaluation studies of the different canopy models. As input data sets, results will be used from the literature and from ongoing activities performed in part within BIPHOREP (Pinus sylvestris; Hartheimer Wald, Hartheim, Germany; Picea abie
Das Projekt "Validierung von Reaktionsmechanismen fuer die Gasphasenchemie der Troposphaere" wird vom Umweltbundesamt gefördert und von Forschungszentrum Jülich GmbH, Institut für Chemie und Dynamik der Geosphäre durchgeführt. Validierung von chemischen Mechanismen durch Vergleich von Modellrechnungen mit Feldexperimenten; - Beruecksichtigung neuer kinetischer Daten, Abschaetzen des Einflusses von ausgewaehlten Reaktionen; - Implementierung in das Chemie- und Transportmodell EURAD.