TitleAtmospheric Modelling at MSC-W

David Simpson and Leonor Tarrason

TFIAM - Haarlem, 7-9 May 2003

EMEP Unified Model I

Meteorologisk Institutt met.no

Horizontal resolution: Regional 50 x 50 km2 (170 x 133 cells, centered over Europe)

Vertical resolution: 20 σ-layers (up to 100 hPa), 10 in PBL

Off-line meteorology: 3-h meteorological input from HIRLAM

Boundary conditions: Flexible choice (modelled from Oslo CTM2, TM3 or climatological Logan data for O3). Currently climatological BCs are used.

Emissions: EMEP emissions estimates for SOx, NOx,NH3, VOC,CO PM2.5 and PM10 from TNO-CEPMEIP project

Schematic structure of EMEP UNIFIED

Boundary, lateral and initial conditions

Advection (Bott scheme)

Dry and Wet Deposition

Emissions

UNI - ACID EMEP acidification10 species + PPM

UNI - AEROEMEP acidification

14 species, 4 size modes

UNI - OZONE EMEP photochemistry

69 species, 170 reactions

Aerosol dynamicsMultimono

Meteorological conditions

PPM mass: 2 species

SOA module

Main developments in UNI-OZONE since July 2002

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• Dry deposition routines 1) Ecosystem-dependant outputs.

2) Introduction of the effect of NH3 in SO2 surface resistance

• Emission routines1) New description of height of emission by sector

(specially for power combustion and industrial sources). 2) New gridded data for PM10 and PM2.5 from TNO/CEPMEIP

• Wet deposition routines1) Heterogeneous sulphur chemistry explicitly introduced

• Chemistry1) Introduction of oxidant limitation in sulphur chemistry2) Introduction of coarse nitrate

UNI-OZONE – the basic conflict:

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―Model should be Operational as Soon as Possible• e.g. For IAM tests

―Model should perform as perfectly as possible

• For S & N compounds, O3, AOTs, exceedances• From 1980s to year 2010

O3 daily maxTimeseries

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1995 2000

O3 daily maxSelection of stations active since 1990 (18)

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1990 Bias=-30%, r=0.73 2000 Bias=-18%, r=0.50

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NO2 – All EMEP stations

NO2 correlation coefficient in city areasCITY DELTA model intercomparison1999

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Paris, day Paris, nigth Milan, night Milan,day (EMEP Unified in orange)

Conclusions on EMEP model O3 performance

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The UNIFIED EMEP model performance has studied in comparison with EMEP stations for 1990,1995 and 2000 and in CITY DELTA stations for 1999.

Correlation coefficients in regional scale are high, between 0.6 and 0.8 for daily mean ozone and daily max values. The summer mean ozone bias is below 10%.

For NO2, correlation coefficients at regional scale vary between 0.5 and 0.7 but the model has difficulties to reproduce at night time NO2.

At Mediterranean stations, model performance is poorer than in average for the rest of Europe, as expected given uncertainties in transport, emissions, and boundary conditions for Mediterranean regions.

Frequency distributions show that the model tends to underestimate high ozone values: the model tends to underestimate exceedance days.

Some changes likely when deposition routines “settle down” - likely more O3 in model.

Note that the underestimation of high ozone values is more pronounced at the end of the 1990s consistent with the general trend of increase of ozone mean values

New Targets? Recent Developments in Crtitical Levels/Loads Discussions

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• AOTx or Fluxes? 1) AOTx still recommended for crops, forests and seminatural vegetation

2) Flux approach for wheat and potato possible.

• AOTx?1) AOT40 maintained for crops and seminatural2) AOT40 and AOT30 perform similarly for forests- AOT40 kept

3) modified AOT30 – mAOT30 for short-term CL 4) CLs: 3 ppm.h for crops/seminatural 5 ppm.h for forests

• Flux CLs, thresholds?1) CL suggested for wheat and potato.2) Threshold of 6 nmole/m2/s for wheat ( – about 20 ppb at full

conductance).... over 4 week period3) Suggestion for alternative flux approach for deciduous forest -

based upon beech. Threshold of 1.6 nmole/m2/s ... over growing season.

New Targets? Recent Developments in Crtitical Levels/Loads Discussions

Meteorologisk Institutt met.no

• Change: height of AOT40 AOTx and fluxes should both be estimated at the top of the canopy.

• Measurements are usually made at 3—5 m above ground level. • Methods are suggested for converting measured data to the appropriate

height.• For crops, this will give lower levels of AOT40 – less exceedance• For forests, this will give higher levels – more exceedance.

Forests: new CL = 5000 ppb.h

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Landuse Issues

Meteorologisk Institutt met.no

If EMEP delivers ecosystem-specific deposition estimates, should landuse maps be harmonised?

Current maps:

1) SEIY map:200 categories – explicit wheat, barley, etc.Basis for current deposition moduleCovers full EMEP model area

2) CCE map16 categories – based upon CORINE/PELCOMlink to ecosystems?

3) CCE- maps for eutrophication/acidification??

4) Other – national maps, 'new' maps (satellite, JRC, etc.)•

1

EMEP Model Evaluation

• Decided at TFMM, Valencia, 2003

• Thorough Review of EMEP model

• For presentation at November, 2003 workshop, Oslo, and TFMM, April 2004

• Compare with measuments, models

• Process investigations

• Identified projects:

– Sweden (IVL): ecosystem deposition

– Netherlands (TNO): model intercomparison

– Others ... during May 2003

Contributions

• Consider choice of parameterisations, chemistry, inputs, etc.

• Quantify “state-of-the-art”

• Identify key field measurements

• Examine source-receptor relationships compared to national studies.

• EMEP MSC-W to prepare full documentation

• See www.emep.int

Immediate future:

• Deliver!– Model is “ready to run”– Test runs to IIASA / IER (MERLIN)– 4-6 countries– Different emission levels– Investigate linearity