CHIMERE air quality forecasts : results during Pays de la Loire summer 2004 experiment and end-user point of view

Arnaud REBOURS - AIR PAYS DE LA LOIRE

ACRI-ST

1st CHIMERE workshop 21, 22 March 2005 -Palaiseau France

French air pollution control networks organization

Air Pays de la Loire

NANTES

PARIS

Pays de la Loire region : 3 200 000 inhab.; 32 000 km2

2 missions : air quality survey and information

Air Pays de la Loire

Territorial cover

La Roche/Y

Cholet

Laval

St-Nazaire

10 survey zones 50 survey sites continuous control 15 minutes time resolution

Nantes

Le Mans

Angers

Modelisation tools Regional scale : Calgrid

10 august 2003

Street scale : OSPM

NO2 - Nantes 2001

Industrial scale : Calpuff 11 feb. 2003 - refinery

Scenario mode

CONTEXT 18 june 2004 french regulation : during pollution episodes, air quality public information is based on observations or on risk of exceedings of thresholds -> necessity of forecasting development

Period : 13 july - 12 october 2004

Summer 2004 experiment : operation by ACRI-ST of an air quality forecast system based on MM5-CHIMERE over the Pays de la Loire region

LOCAL FORECASTING PLATFORM

2 zones : Great West area (15 km) and Pays de la Loire region (5 km)

GWEST 15 km

APL 5 km

2 pollutants : O3 and NO2

4 daily outputs : D-1, D, D+1 and D+2 hourly time step

Inputs Outputs

Emissions inventory : 5km and 50 km

Meteorological data : NCEP

Continental chemistry : PREV ’AIR

2D Data

Platform publication

Maps

Forecast computer : MM5-CHIMERE

Interface computer

Job programmer

LOCAL FORECASTING PLATFORM

Meteo-rology

pollution

zone

pollutant4 days forecasts

WEB INTERFACE

FORECAST PRELIMINARY RESULTS Observation data : 20 survey sites

Statistical criteria : BIAS and NMSE

BIAS : D0 FORECAST

-30

-20

-10

0

10

20

30

APL>0GWEST>0PREVAIR>0APL>120GWEST>120PREVAIR>120

FORECAST PRELIMINARY RESULTS

ozone

BIAS : D+1 forecast

-30

-20

-10

0

10

20

30

APL>0GWEST>0PREVAIR>0APL>120GWEST>120PREVAIR>120

FORECAST PRELIMINARY RESULTS

ozone

BIAS : D+2 forecast

-30

-20

-10

0

10

20

30

APL>0GWEST>0PREVAIR>0APL>120GWEST>120PREVAIR>120

FORECAST PRELIMINARY RESULTS

ozone

NMSE : D+1 forecast

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

200% APL>0GWEST>0PREVAIR>0APL>120GWEST>120PREVAIR>120

FORECAST PRELIMINARY RESULTS

ozone

FORECAST PRELIMINARY RESULTS

NO2

Bias : D+1 forecast

-20

-15

-10

-5

0

5

10

15

20 APL>0GWEST>0PREVAIR>0APL>20GWEST>20PREVAIR>20

FORECAST PRELIMINARY RESULTS

NO2

NMSE : D+1 forecast

0%

100%

200%

300%

400%

500%

600% APL>0GWEST>0PREVAIR>0APL>20GWEST>20PREVAIR>20

POST-PROCESSING ON FORECASTS Vigilance maps improve public information

13 alert zones :5 departments (counties), 7 agglomerations, 1 industrial area

3 symbolic colours : green, orange, red

calculatio

n

2 ways :forecasting

observationvalidati

on

POST-PROCESSING ON FORECASTS Vigilance maps improve public information

Forecasted exceeding

Procedure activating conditions

- agglomerations :

2 sites

- departments :

2 agglomerations or

30% of the zone

communiqués (fax and e-mail) web site : www.airpl.org

POST-PROCESSING ON FORECASTS Vigilance maps improve public information

POST-PROCESSING ON FORECASTS

Air quality index prediction

(D 1 ,...)=

Annualmaps

Exceedings evaluations of limit values, quality objectives and target values

CONCLUSION

Forecast results are acceptable for ozone and better than continental modeled values for NO2 Local platform brings helps to diagnosis : background pollution in the great west of France, influence of Paris pollution, meteorological forecast parameters

Post processing improve air quality information in connection with alert system or daily pollution

PROSPECTS

Integration of detailed emission calculations (AIREMIS)

Integration of meteorological and pollution vertical profiles

Local platform should be operated by Air Pays de la Loire during summer 2005

Statistical adaptation of modeled results with observations for D-1 and D steps