Atmospheric modelling activities inside the Danish AMAP program

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Atmospheric modelling activities inside the
Danish AMAP program

• Jesper H. Christensen
• NERI-ATMI, Frederiksborgvej 399
• 4000 Roskilde

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The Danish Eulerian Hemispheric Model (DEHM)
System

• The model work is financially supported by the
  Danish Environmental Protection Agency with means
  from the MIKA/DANCEA funds for Environmental
  Support to the Arctic Region
• It is a part of the Danish contribution to the
  international AMAP programme
  
• Purpose Study the long-range transport in the
  troposphere of pollutants into the Arctic
  
• Developed since 1990. In the beginning only for
  Sulphur, later Lead and now also with a full
  photochemical scheme and Mercury.
  

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The Danish Eulerian Hemispheric Model in 1. Phase
of AMAP

• Direct coupling to ECMWF data, no MM5
  meteorological preprocessor
  
• Simplified linear sulphur chemistry

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The Danish Eulerian Hemispheric Model (DEHM)
System
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MM5 model

• Hydrostatisk version (version 2)
• 150 km resolution at 60 N, 50 km for nested
  domain
  
• 97x97 horizontal grid-points (for mother domain
  and 100x100 horizontal gridpoints for nested
  domain) and 20 vertical layers
  
• Mixed Phase (Reisner) explicit moisture
• Betts-Miller cumulus parametrization
• MRF boundary layer parametrization with 5 layer
  soil model
  
• Cloud-radiation scheme

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• Input data
• Met data from ECMWF, 2.5x2.5 lat-lon,
• 12 hour resolution, 21 years data from
  1979 to 2000
  
• Output every 3 hours
• Only run for 1990 to 2000 for hemispheric domain
  and
  
• for 1995 and 1998 to 2000 for Europe (50 km)
• 1 month for Greenland (50 km) as demonstration

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The Danish Eulerian Hemispheric Model

• Full three dimensional advection-diffusion
  equations
  
• 150 km grid resolution (Mother domain)
• 20 vertical levels up to 16 km
• Dry deposition based on the resistance method
  with 8 different surfaces
  
• Wet deposition based on scavenging coefficients
• Numerical methods
• Horizontal advection Accurate Space Derivatives
  with non-periodic boundary conditions and 2-way
  nesting capabilities
  
• Vertical advection Finite Elements
• Diffusion Finite Elements

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Nested version of DEHMa demonstration with the
simplified sulphur version
150 km resolution
50 km resolution
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The monthly mean concentrations for SOX
150 km resolution
50 km resolution
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Mercury version of DEHM

• Mercury model with GKSS chemistry
• Gas phase pollutants Hg0 , HgO, HgCl2 and
  particulate Hg
  
• 9 aqueous phase pollutants
• Chemistry depending on O3, SO2, Cl- and Soot
• During the polar sunrise in the Arctic an
  additional fast oxidation rate of Hg0 to HgO is
  assumed
  

From Petersen et al. (1998)
Wet removal rates for all aqueous phase
pollutants as for Sulphate Dry deposition velo
city for HgO and HgCl2 as for HNO3 and for
particulate Hg as for Sulphate
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Examples of results with mercury model
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Photochemical version of DEHM

• Pollutants 54 species, more than 110 chemical
  reactions, chemistry scheme similar to the EMEP
  oxidant model
  
• Emissions Global GEIA emissions of anthropogenic
  emissions of SOX and NOX, NOX from lightning and
  soil and Isoprene form vegetation, all on 1x 1
  
• global EDGAR inventory on 1x 1 for
  anthropogenic hydrocarbons
  
• SOX and NOX for Europe from EMEP
• Has been run for whole 1998

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Purpose with the photochemical version

• Improvement of the parameterization of the
  chemistry compared to the simple sulfur model
  
• Provided necessary input concentrations for the
  Mercury model
  
• Be a useful contribution for the understanding of
  the atmospheric chemistry in the Arctic,
  especially during the Polar Sunrise in connection
  with field measurements
• Provided necessary hemispheric background
  concentrations for the regional models, e.g. for
  Europe

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Results from chemical version
NO2 mean concentrations
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Ozone mean concentrations
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Example of ozone transport into theNorth
Atlantic
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Some validations
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Ozone in the Arctic
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Ongoing activities and future work

• Continuing the work with parameterization of
  background chemistry, coupling with aqueous
  chemistry
  
• Nested model calculations for Europe
• Improve parameterization of Arctic chemistry,
  coupling with GOME measurement of BrO, coupled to
  measurements in the Arctic in order to understand
  the spatial and temporal distribution of the
  depletion

From Richter et al. (1997)
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ACKNOWLEDGEMENTS

• The model work is financially supported by the
  Danish Environmental Protection Agency with means
  from the MIKA/DANCEA funds for Environmental
  Support to the Arctic Region