48
E. van der Swaluw et al.
8.1 Introduction
The Netherlands ranks second in value of agricultural export [2]; hence, the impact
of nitrogen deposition on ecosystems is a relevant issue in the Netherlands. Recently
there have been a few papers published [3, 5], which focus on the question whether
the reported decline in ammonia emissions in the Netherlands is reflected in atmospheric concentration time series. The reason to focus on concentrations instead of
deposition is that measurements of deposition are very scarce, whereas measurements
of ammonia concentration are available on a much denser scale in the Netherlands.
There is no direct linear relation between ammonia emissions and concentrations,
because the ammonia concentrations in the atmosphere are also influenced by meteorology, atmospheric chemistry and the dependence of deposition on the acidity of
the surface on which the deposition takes place. Both the atmospheric chemistry and
the acidity of the surface also change over the periods considered, because they both
depend on the concentration of both sulphur and nitrogen components in respectively
the atmosphere and the surface layer.
Wichink Kruit et al. [5] use the OPS model in order to quantify the effects of meteorology and physicochemical processes on atmospheric ammonia concentrations. The
OPS model is a source-receptor model, which combines a Gaussian plume model
approach for local applications with a Lagrangian trajectory model for long-range
transport. Chemistry in the OPS model is parametrized and therefore less robust than,
for example, a chemical module in a Eulerian chemistry transport model.
Here we adopt the EMEP4NL model in order to calculate ammonia concentrations
and related components over the Netherlands over a period of 10 years, i.e. from
2006 to 2015. The calculations are performed on an embedded grid with the highest
resolution of 2.0 × 1.3 km over the Netherlands.
8.2 The Models Used Over the Period 2006–2015:
EMEP4NL and OPS
The EMEP model [1] is employed in this paper (as EMEP4NL), in order to make
calculations over the Netherlands at high resolution for the purpose of a trend analysis.
We follow the same approach as Vieno et al. [4], who couples the output of the WRF
model for the meteorological data in order to drive the EMEP model in off-line mode
over the UK (as EMEP4UK). An embedded grid is used with four layers; the coarsest
one is over the whole of Europe at a resolution of a half degree, the highest resolution
is over the Netherlands, with a resolution of 2.0 × 1.3 km.
Emissions are taken from MACC III for countries outside of the Netherlands,
and spatially more detailed emissions for the Netherlands itself. Emission totals per
SNAP sector per country are used over the period 2006–2015, according to the latest
CEIP expert estimates.
E. van der Swaluw et al.
8.1 Introduction
The Netherlands ranks second in value of agricultural export [2]; hence, the impact
of nitrogen deposition on ecosystems is a relevant issue in the Netherlands. Recently
there have been a few papers published [3, 5], which focus on the question whether
the reported decline in ammonia emissions in the Netherlands is reflected in atmospheric concentration time series. The reason to focus on concentrations instead of
deposition is that measurements of deposition are very scarce, whereas measurements
of ammonia concentration are available on a much denser scale in the Netherlands.
There is no direct linear relation between ammonia emissions and concentrations,
because the ammonia concentrations in the atmosphere are also influenced by meteorology, atmospheric chemistry and the dependence of deposition on the acidity of
the surface on which the deposition takes place. Both the atmospheric chemistry and
the acidity of the surface also change over the periods considered, because they both
depend on the concentration of both sulphur and nitrogen components in respectively
the atmosphere and the surface layer.
Wichink Kruit et al. [5] use the OPS model in order to quantify the effects of meteorology and physicochemical processes on atmospheric ammonia concentrations. The
OPS model is a source-receptor model, which combines a Gaussian plume model
approach for local applications with a Lagrangian trajectory model for long-range
transport. Chemistry in the OPS model is parametrized and therefore less robust than,
for example, a chemical module in a Eulerian chemistry transport model.
Here we adopt the EMEP4NL model in order to calculate ammonia concentrations
and related components over the Netherlands over a period of 10 years, i.e. from
2006 to 2015. The calculations are performed on an embedded grid with the highest
resolution of 2.0 × 1.3 km over the Netherlands.
8.2 The Models Used Over the Period 2006–2015:
EMEP4NL and OPS
The EMEP model [1] is employed in this paper (as EMEP4NL), in order to make
calculations over the Netherlands at high resolution for the purpose of a trend analysis.
We follow the same approach as Vieno et al. [4], who couples the output of the WRF
model for the meteorological data in order to drive the EMEP model in off-line mode
over the UK (as EMEP4UK). An embedded grid is used with four layers; the coarsest
one is over the whole of Europe at a resolution of a half degree, the highest resolution
is over the Netherlands, with a resolution of 2.0 × 1.3 km.
Emissions are taken from MACC III for countries outside of the Netherlands,
and spatially more detailed emissions for the Netherlands itself. Emission totals per
SNAP sector per country are used over the period 2006–2015, according to the latest
CEIP expert estimates.