Integrated modelling and monitoring for use in forecasting Jørgen Brandt and Finn Palmgren

Integrated modelling and monitoring for use in forecasting

Jørgen Brandt and Finn Palmgren

National Environmental Research InstituteDepartment of Atmospheric Environment

Denmark

During the last decades, there has been a strong integration between atmospheric monitoring and modelling at NERI with focus on human exposure, human health, marine and terrestrial ecosystems, process understanding, etc.

The modelling and the monitoring have been closely designed to supplement each other for optimal application at the different scales:urban street canyons, urban background, near city background, rural background and remote

The model results at all scales has been fully implemented in the general monitoring of air quality in Denmark

The monitoring data have been used for the general model development strategy (e.g. defining the problems to be modelled), validation, estimation of emission factors, etc.

Integrated modelling and monitoring strategy

Integrated monitoring strategy• Permanent monitoring stations for “standard pollutants”

located in the typical environments: streets, urban background, “near city” background, rural background and remote.

• Measurement campaigns of more advanced measurements established at the permanent monitoring sites.

• Application of air quality models and receptor models for data analysis.

• Application of air quality models for nowcast and forecast, e.g. for information to the public.

N

B a c k g ro u n d N e tw o r k

U rb a n N e tw o rk (L M P ) tr a ffic u rb a n b a c k g ro u n d ru ra l

100 km

Aalborg

Århus

Lille ValbyKøben-havn

O dense

Keldsnor

Measurements

256 m

Measurements at elevated sites

• Long range transport of air pollutants is important in Scandinavia

• Measurements at ground level are influenced by local sources and deposition

• The combination of measurements at ground level and at 260 m to be used for development and validation of regional models

Monitoring stations in Copenhagen

HCØ (urban background)

HCAB (street)

Jagtvej (street)

The THOR Integrated Model System (http://thor.dmu.dk)

Global met. data from NCEP/ECMWF

NWF model (Eta/MM5)

Long range transport model (DEHM-REGINA)

Urban background model (UBM) and point source model

(OML)

Street canyon model (OSPM)

Emission and traffic models

Accidental release model (DREAM)

~3000 visualizations and animations of weather and air

pollution, four times a day

Subset to decision makers, web site, radio, TV,

newspapers, the public, etc.

Emission and traffic scenarios

Decision makers

Human exposureHuman health

Marine models, Terrestrial models,

Socioeconomic models

National range model(DEHM-DK)

Real-timemeasurementsSatellite data

Data assimilation

Climate model results/scenarios

Global/hemispheric modelDEHM

Monitoring dataField experiments

AirGis

The Danish Eulerian Hemispheric Model, DEHM

• Long-range transport of tropospheric air pollution in the Northern Hemisphere and Europe

• 60 chemical species• Full three dimensional

advection/diffusion equations • Two-way nested modelling over

Europe and northern Europe (3 domains)

• 150 / 50 / 16.67 km grid resolution• 20 vertical levels up to 16 km• Model run and validation for a

period of 16 years (1989 to 2004)• Meteorological driver; MM5

nested over Europe or Eta (Europe)

O3

NO2

Background Urban Model, BUM

• Gaussian plume model (horizontal) and linear dispersion to Hmix (vertical)

• Input data: - Meteorological forecast from the Eta model - Air pollution forecast from DEHM - Emissions of NOx, CO, benzene and PM10• Output: hourly values of O3, NO,

NO2 , NOx , CO, benzene and PM10• Resolution ~ 500 m - 2 km• Validated for e.g. Copenhagen and Aalborg (Denmark), • Has been tested as part of CityDelta,

including eight cities in Europe

372.80

725.49

465.62

490.90

118.10

269.42

394.89

426.42

185.07

346.17

341.78

250.54

296.73

282.31

530.15

219.53

243.96

696.46

415.63

350.20

202.10

20.43

338.21

523.19

496.51

736.19

347.03

358.45

67.36

109.56

215.34

322.53

526.54

420.84

277.85

0.00

0.00

1.02

3.06

32.72

262.91

238.79

0.00

0.00

0.00

0.00

3.06

20.72

67.86

-6000 -4000 -2000 0 2000 4000 6000

-6000

-4000

-2000

0

2000

4000

6000

Jagtvej

NOx emissions [kg/day]

NO2

conc.g/m3

Operational Street Pollution Model, OSPM• Street canyon model• Combined plume model (leeward

side of the street) and box model

(windward side)• Input: - Meteorological forecast from the Eta model - Air pollution forecast from DEHM and the Urban Background Model, BUM - Street configuration - traffic data• Output: O3, NO, NO2, NOx, CO,

benzene and PM10• Forecasts at both sides of the street• Used and validated for e.g.

Copenhagen and Aalborg and many other places

NO + O3 NO2

NO2 + hv O3 + NO

Roof level wind

Recirculating air

Direct plumeLeewardside

Windwardside

Background pollution

Air quality forecast for the cities of Copenhagen and Aalborg

+ local radio, TV and newspapers

Time series of concentrations at Aalborg roof level (left) and concentrations (right) at Aalborg street level

Conclusions and future work

• By integrating modelling and monitoring at all scales and typical environments, we gain a better understanding of the governing processes, better models and better monitoring programmes.• Since 1998 we have operationally produced three-days air quality forecasts at the different scales: European/regional, urban background and urban street.• Ongoing developments include models with even higher resolution (1 km x 1 km at national scale) and implementation of data assimilation techniques.

Data assimilationWe are right now in the process of implementing different data assimilation techniques in the models• 4D-Var and Optimum Interpolation for regional models• Kalman filtering for urban models

Data assimilation will, of course, be important for the air quality forecasts at all scales

However, the technique will also be applied in connection with the monitoring programmes to make better estimates of e.g. human exposure or deposition of nitrogen to ecosystems, etc., in all areas where measurements are not carried out.

Acknowledgements

• NCEP kindly provides global meteorological forecast data• EMEP kindly provides air pollution measurement data and emission data

Further information

• THOR system (description of the system): http://thor.dmu.dk• THOR system (demo): http://www.dmu.dk/AtmosphericEnvironment/thor/index.html

• Operational Air Forecast, actual air quality data, etc.: http://luft.dmu.dk• City of Copenhagen: http://www.miljoe.kk.dk/luftudsigt• City of Aalborg: http://www.aalborg-trafikinfo.dk

• or e-mail: [email protected] or [email protected]