Gloream workshop, Paris 2006 Setting of an experimental forecast system for air quality at ECMWF in the framework of the GEMS project : implementation and first results Forêt (1),(2) G., Monge (2) J-.L., Menut (2) L., Vautard (3) R., Beekmann (1) M. (1)Laboratoire Inter-universitaire des Systèmes Atmosphériques (LISA) (2)Laboratoire de Météorologie Dynamique (LMD) (3)Laboratoire des Sciences du Climat et de l’Environnement (LSCE)

Context of this work ▪ 3D Chemical Transport Model are now used to assess air pollution from global to urban scales… nevertheless large uncertainties remains: external forcings : emissions, meteorology, chemical boundary conditions representation of dynamics : pollutants dispersion representations of chemical and physical mecanisms (gases and aerosols) numerical representation ▪ Great Potential for increasing CTM performances : increasing number of teams working on AQ modelling increasing computing capacity multiplication of observations (satellites)  Synergetical approach via integrated projects : GEMS, PROMOTE

Gloream workshop, Paris 2006 A common will to ameliorate air quality modelling : The GEMS project Purpose of GEMS (Global and regional Earth-system Monitoring using Satellite and in-situ data) : ● Global Monitoring system for Greenhouse Gases (GHG) ● Global Monitoring system for Reactive Gases (GRG) ● Global Monitoring system for Aerosols (AER) ● Regional Air-Quality Monitoring and Forecasting (RAQ) Create a new European system for operationnal global monitoring of Atmospheric chemistry and to produce improved medium-range & short range air-chemistry forecasts.  GEMS sub-projects :

The GEMS RAQ sub project ▪ Provide, Evaluate NRT forecasts (gases and aerosols) at continental to regional scale, relying on global and regional assimilated fields ▪ Improve existing continental to regional scales air quality models, statistical post-treatment, and explore multi-model ensemble approaches ▪ Use of satellite information for air quality prognoses ▪ Impact of the global change on regional air quality ▪ European cooperation for data access, skill evaluation and forecasts comparisons ▪ Evaluate health impact of air quality and produce dedicated products Gloream workshop, Paris 2006 Objectives :  Several AQ model used for sensivity studies and cross-comparison exercices  Recommandation for future RAQ modelling systems

Gloream workshop, Paris 2006 The CHIMERE-GEMS system (1/2) Starting model version  based on the operationnal PREV’AIR platform : ( GFS/NCEP Global meteorological forecasts MM5 Regional meteorological forecasts CHIMERE Regional CTM Prognose hourly concentrations : gases (O 3, NO 2, CO, SO 2 …) aerosols (Sulf, Nitrate,…) EMEP emissions USGS land use, land cover LMDZ-INCA (gases) GOCART (aerosols) Large scale chemical forcing from monthly climatology ● gaseous chemistry module ● aerosols module ● advection, turbulence ● dry and wet deposition

Gloream workshop, Paris 2006 The CHIMERE-GEMS system (2/2) The CHIMERE-GEMS version : Geographical GEMS domain [35°N-70°N; 15°E-35°W] Horizontal resolution 101x71 cells ; 0.5°x0.5° Vertical resolution 8 levels ; top at 500 hPa New emission cadaster (from TNO; 6kmx6km over Europe)  spring 2007 Forecasted boundary chemical fields for gases (GRG) and aerosols (AER)  june 2007 Meteorological forcing from Integrated forecasting System (ECMWF)  Test over a summer period (2005)  Installing an operationnal system at ECMWF

Impact of ECMWF meteorological forcing (1/6) Simulation period : June/July/August 2005 Number of stations : ~ 200 stations (urban+rural+peri-urban) Skill scores of the forecasts for surface ozone daily peaks values (µg.m 3 ) Bias Cor Rms Gloream workshop, Paris 2006 GFS IFS Change of the meteorological forcing in the forecasting system Global met. frcst GFS (NCEP) (1°x1°) Regio. met. frcst MM5 (0.5°x0.5°) Regio. Chem. rcst CHIMERE-GEMS Global met. frcst IFS (ECMWF) (0.5°x0.5°) Regional chem. frcst CHIMERE-GEMS

Gloream workshop, Paris 2006 biasrms Impact of ECMWF meteorological forcing (2/6) correlation

Example of ozone surface peaks time-series : Gloream workshop, Paris 2006 Impact of ECMWF meteorological forcing (3/6)

Gloream workshop, Paris 2006 GFS meteorological forcingIFS meteorological forcing [Number of simulated ozone peaks (> 180 µg.m -3 ) / number of observated peaks ] x 100 ● blacks circles shows stations without peaks values above 180 µg.m -3 Impact of ECMWF meteorological forcing (4/6)

GFS meteorological forcing IFS meteorological forcing Number of forecasted but not observed peaks : False alert Number of « well » forecasted peaks : correct alert Gloream workshop, Paris 2006 Impact of ECMWF meteorological forcing (5/6)

Test ECMWF meteorological forcing for summer 2005 (6/6) Exploratory analysis of differences between both meteorological forcings  example of monthly mean differences maps (July 2005) Gloream workshop, Paris m Temperature (°C)Wind module (m/s) Friction velocity (u*; cm/s) Relative humidity (%) [var IFS -var GFS ]

Gloream workshop, Paris 2006 Devellopment of a new experimental forecast system based at ECMWF Simulation period : July/August 2006 Number of stations : ~ 200 stations (urban+rural+peri-urban) Skill scores of the forecasts for daily peaks values (µg.m 3 ) Bias Cor Rms GFS IFS What’s new ? New parallel version of CHIMERE is used The whole system is running remotely on ECMWF’s calculator (HPCD) IFS (ECMWF) (0.5°x 0.5°) CHIMERE-GEMS (parallel version) 120 h IFS forecast available Timing (D-1) 6h30 pm (UT) (D-1) 9 pm (UT) Beginning of the CHIMERE run on hpcd (D-1) 9h45 pm (UT) Chemical forecasts are Available (Day + 3)

Experimental forecast for summer 2006 at ECMWF Gloream workshop, Paris 2006 Simulated surface ozone peaks for the 2006/07/26 NCEP/MM5/CHIMERE ECMWF/CHIMERE-GEMS

Gloream workshop, Paris 2006 Future works  Identifying main differences for the 2 differents meteorological forcings  increasing horizontal resolution of the model (parallel version)  Tests with the new TNO emission cadaster  Sensivity tests to chemical boundary conditions forcings : differences between monthly global climatology and global chemical forecasts  currently in test with LMDZ-INCA chemical forecasts + Implementation of the new model version : (spring 2007 ???) enhanced aerosol modules deep convection  free-tropospheric version coupling with chimere-dust version  better dust forcing …