Forschungsprogramme
(Englisch)
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COST-Action ES0603 - Assessment of production, release, distribution and health impact of allergenic pollen in Europe
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Kurzbeschreibung
(Englisch)
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The overall goal of this project is to investigate birch pollen production and emission by combining experimental and modeling work in order to quantify the released pollen in relation to turbulence characteristics and micrometeorological parameters around a pollen source. Emission parameters are the least known part of the new generation of pollen forecast systems, which are based on transport and dispersion models. A second focus is the development and validation of a pollen emission scheme based on the results from the present field campaign. Furthermore, this scheme will be tested using state-of-theart atmospheric transport models which are optimized by the measured exchange conditions. The models are the LM-ART and/or other models used by COST partners.
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Partner und Internationale Organisationen
(Englisch)
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AT, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GR, HR, HU, IE, IL, IT, LT, LV, NL, NO, PL, PT, RS, SE, SI, SK, TR, UK
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Abstract
(Englisch)
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Diseases due to aeroallergens constantly increased over the last decades and nowadays affect up to 15-25 % of the European population. Adequate protective measures require reliable forecasting of their atmospheric dispersion. New generation pollen forecast systems range from fully dynamical dispersion modelling embedded in a numerical weather prediction model (NWP) to statistical/NWP combinations, in order to provide pollen forecasts with full spatial coverage. These systems, however, suffer above all from the gaps in knowledge on the physical and biological processes that determine the pollen emission. The MicroPoem study aimed at investigating pollen production and emission by combining experimental and modelling work in order to quantify the released pollen and describe dispersion characteristics as function of meteorological variables. Micrometeorological analyses focused on reproducing the observed downwind pollen distribution by using a local-scale dispersion model. The field experiment around a spatially well-defined birch pollen source, equipped with three micrometeorological towers, 26 pollen traps, a SODAR and a tethered balloon system, was conducted during the birch pollen season in spring 2009. Since different pollen sampler types and orifice orientations were used, the study also addressed pollen aspiration efficiency and correction techniques. An additional field intercomparison was conducted during the birch pollen season in spring 2010, which provided an insight into common difficulties in pollen monitoring, above all for the case of upwards-facing blunt samplers. From the data a correction model was derived, which notably improves the agreement of the different sampler types. The analysis of the birch pollen dispersion indicated that the distribution of the background concentration around the isolated source, which acts as a wind break, is not trivial. Therefore, a CFD model was used to simulate the background concentration as well as the pollen dispersion from the source. The preliminary results indicate a large influence of the wind break on the downwind background concentration due to lower wind velocities, decreasing the pollen settling distance behind the wind break. The measurements also indicate a large influence of wind direction and velocity on the downwind pollen distribution, which could be reproduced with the Lagrangian as well as the CFD model. On the base of the extensive dataset the most important micrometeorological factors governing the emission can be identified. The knowledge on these key factors can be used to derive an empirical emission parameter. The new parameter will improve the accuracy of the emission term in current long-range pollen transport models. The knowledge gained in the present study will help to better understand the impact of physical processes on pollen emission and will enhance the quality of forecast systems as well as the reliability and comparability of pollen measurements.
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