Improved modelling of atmospheric ammonia over Denmark using the coupled modelling system DAMOS

Abstract

A local-scale Gaussian dispersion-deposition model (OML-DEP) has been coupled to a regional chemistry-transport model (DEHM) in the Danish Ammonia Modelling System, DAMOS. Thereby it has been possible to model the distribution of ammonia concentrations and depositions on a spatial resolution down to 400 m × 400 m for selected areas in Denmark. DAMOS has been validated against measured concentrations from the dense measuring network covering Denmark. Here measured data from 21 sites are included and the validation period covers 2–5 yr within the period 2005–2009. A standard time-series analysis (using statistic parameters like correlation and bias) show that the coupled model system captures the measured time-series better than the regional scale model alone. However, our study also shows that about 50% of the modelled concentration level at a given location originates from non-local emission sources. The local-scale model covers a domain of 16 km × 16 km and of the locally released ammonia (NH<sub>3</sub>) within this domain, our simulations at five sites, show that 14–27% of the locally emitted NH<sub>3</sub> also deposit locally. These results underline the importance of including both high-resolution locale-scale modelling of NH<sub>3</sub> as well as the regional scale component described by the regional model. The DAMOS system can be used as a tool in environmental management in relation to assessments of total nitrogen load of sensitive nature areas in intense agricultural regions. However, high spatio-temporal resolution in input parameters like NH<sub>3</sub> emissions and land-use data are required

Risk of exposure to airborne <i>Ambrosia</i> pollen from local and distant sources in Europe – an example from Denmark

“…This concept of combined LDT and local scale calculations has been shown to work for air pollutants (e.g. Geels et al [27], Hertel et al [39]), and is considered usable for urban scale calculations of aeroallergens once urban scale maps of aeroallergen sources have been produced [25]. By combining local and regional scale processes and explaining the near source distribution of pollen by the use of models, the current study addresses one of the major challenges in the understanding of airborne pollen transport [40].…”

“…Forwards calculation with a Gaussian plume model was used to estimate the concentration profile at trap height (roof level) of Ambrosia pollen grains released at the surface. Here we use the idealised approach in a similar way to that by Skjøth et al [25], by using the OML [26] model from the DAMOS system, which is designed to combine regional scale and local scale calculations [27]. This approach allows simulations of concentration profiles at any roof-top height using either surface emissions from grasses or weeds or emissions from trees [25].…”

Ammonia Concentrations Over Europe – Application of the WRF-Chem Model Supported with Dynamic Emission

“…This simulation is subsequently referred to as "BASE." In the second simulation we ran the WRF-Chem model with hourly variations in ammonia emissions for all of 2012 by using a similar approach as for the Danish Eulerian Hemispheric Model [49], and the ammonia emissions model uses gridded hourly meteorology from WRF-Chem to simulate the hourly emissions variations (a description of the dynamic model is given in the following section). This simulation is in the following referred to as "DYNAMIC.…”

Environmental Impacts—Atmospheric Chemistry

“…Reis et al 2009) and limited access to high-quality emission factors. Uncertainty associated with the national totals may be down to 5-10 % in the most data-rich regions such as Denmark (Geels et al 2012a), but the lack of data and poor emission factors may cause uncertainties of up to a factor of ten in data-poor regions (e.g. Nowak et al 2012).…”