Abstract
Abstract. Common ragweed (Ambrosia artemisiifolia L.) is a highly allergenic and invasive plant in Europe. Its pollen can be transported over large distances and has been recognized as a significant cause of hay fever and asthma (D'Amato et al., 2007; Burbach et al., 2009). To simulate production and dispersion of common ragweed pollen, we implement a pollen emission and transport module in the Regional Climate Model (RegCM) version 4 using the framework of the Community Land Model (CLM) version 4.5. In this online approach pollen emissions are calculated based on the modelling of plant distribution, pollen production, species-specific phenology, flowering probability, and flux response to meteorological conditions. A pollen tracer model is used to describe pollen advective transport, turbulent mixing, dry and wet deposition. The model is then applied and evaluated on a European domain for the period 2000–2010. To reduce the large uncertainties notably due to the lack of information on ragweed density distribution, a calibration based on airborne pollen observations is used. Accordingly a cross validation is conducted and shows reasonable error and sensitivity of the calibration. Resulting simulations show that the model captures the gross features of the pollen concentrations found in Europe, and reproduce reasonably both the spatial and temporal patterns of flowering season and associated pollen concentrations measured over Europe. The model can explain 68.6, 39.2, and 34.3 % of the observed variance in starting, central, and ending dates of the pollen season with associated root mean square error (RMSE) equal to 4.7, 3.9, and 7.0 days, respectively. The correlation between simulated and observed daily concentrations time series reaches 0.69. Statistical scores show that the model performs better over the central Europe source region where pollen loads are larger and the model is better constrained. From these simulations health risks associated to common ragweed pollen spread are evaluated through calculation of exposure time above health-relevant threshold levels. The total risk area with concentration above 5 grains m−3 takes up 29.5 % of domain. The longest exposure time occurs on Pannonian Plain, where the number of days per year with the daily concentration above 20 grains m−3 exceeds 30.
Highlights
Ambrosia artemisiifolia L., is an alien plant that has invaded parts of Europe over the last century, creating severe allergies in populations (Chauvel et al, 2006; Kazinczi et al, 2008; Gallinza et al, 2010; Pinke et al, 2011)
Pollen production is developed in the framework of the Community Land Model (CLM) version 4.5 (Oleson et al, 2013), which is the land surface scheme coupled to Regional Climate Model (RegCM)
This study presents a regional-climatic simulation framework based on RegCM4 for investigating the dynamics of emissions and transport of ragweed pollen
Summary
Ambrosia artemisiifolia L. (common ragweed, hereafter ragweed), is an alien plant that has invaded parts of Europe over the last century, creating severe allergies in populations (Chauvel et al, 2006; Kazinczi et al, 2008; Gallinza et al, 2010; Pinke et al, 2011). One of the goals of the project “Atopic diseases in changing climate, land use and air quality” (ATOPICA) (http: //www.atopica.eu) is to better understand and quantify the effects of environmental changes on ragweed pollen and associated health impacts over Europe In this context the present study introduces a modelling framework designed to simulate production and dispersion of ragweed pollen. Hamaoui-Laguel et al (2015) used the observations collected in Bullock et al (2012), combined with simplified assumptions on plant density and a calibration using observations to obtain a ragweed density inventory map This approach made use of the Organising Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and the Phenological Modeling Platform (PMP) for obtaining daily available pollens (potential emissions) in Europe.
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