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ESCOMPTE MODELING EXERCICE WORKSHOP UAM V 1.31

ESCOMPTE MODELING EXERCICE WORKSHOP UAM V 1.31. Meteorology E. Buisson NUMTECH Chemistry O. Duclaux Total CReS. Photochemical Model UAM-V. The Urban Airshed Model (UAM) program developed by SAI (since 1970) EPA approved Use by Total (Solaize Research Center) since 1998 (Lyon area)

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ESCOMPTE MODELING EXERCICE WORKSHOP UAM V 1.31

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  1. ESCOMPTE MODELING EXERCICE WORKSHOPUAM V 1.31 Meteorology E. Buisson NUMTECH Chemistry O. Duclaux Total CReS

  2. Photochemical Model UAM-V • The Urban Airshed Model (UAM) program developed by SAI (since 1970) • EPA approved • Use by Total (Solaize Research Center) since 1998 (Lyon area) • Comparison of Airqual & UAM V 1.14 • Lidar campaign for evaluation of the model ouput (Etude Lyonnaise de l’Ozone 1999)

  3. Time Advection Turbulent Chemical Emissions Dry Wet dependance Diffusion Reaction Deposition Photochemical Model DescriptionUAM-V 1.31 • Technical formulation : • advection / diffusion equation • solution by finite-difference numerical technique • Multi layer (user define) • Terrain following coordinates

  4. Model Description PhotoChemical Mecanism • Carbon Bond mechanism CB V • 120 reactions : • 10 inorganic species : NO, NO2, O3, CO, HNO2, H2O2, HNO3, NxOy, SO2, SULF, PNA. • 19 organic species : OLE, PAR, TOL, XYL ,FORM, ACET, ETH, CRES, MGLY, OPEN, PAN, ISOP, TERP, ETOH, ALDX, IOLE, PANX, CH4, ISPD • 13 steady state species : O, O1D, NO3, N2O5, OH, HO2, XO2, XO2N, C2O3, CXO3, ROR, TO2, CRO • major critiques of CB-IV resolved in CB V: • low VOC/ Nox ratio (-> two aldehydes species ) • intermediate radical species in aromatics chemistry could accumulate • carbon mass balance • Explicit treatment of key toxic compounds : 1,3 butadiene, benzene, formaldehyde, acetaldehyde

  5. Model Description photolysis rates • Photolysis Rates for seven processes : JNO2, JO1D, JHCHOr, JHCHOs, JACETr, JAcrolein,JALDX Jn =  minƒmaxin() n() () d  • Actinic flux varies in space and time, function of : • extraterrestrial solar flux (Fröhlich & Werhli 1983) • Surface UV albedo • Turbidity • Total O3column density • Calculations of J-Values performed cell-by-cell (model dev. Schippnick & Green 1982) • cloud cover correction (CL > 70 %)

  6. Model Description Transport & Diffusion • Transport advection treated by specified horizontal wind field (RAMS) scheme dev. by Smolarkiewicz (1983) vertical velocity calculated from the conservation mass equation • Turbulent Diffusion : proportional to the concentration gradient (“K-theory”) • Horizontal Dif. calculated based on deformation characteristics of horizontal wind (Smagorinsky 1963) • Vertical turbulent exchange, diagnosed from wind and temp. Fields or directly interpolated from Kv fields (RAMS) • Zero flux conditions on all lateral bound. & top. • The lower boundary condition for vertical diff = dry deposition flux from layer 1 to the surface

  7. Model Description Deposition dry & wet • Dry Deposition Algorithm based on the scheme in the RADM model (Wesely 1989) Fo = - Ci Vd • Deposition velocity is estimated as an inverse sum of a series of resistance ( + V sedimentation for particulate species) • Micrometeorological Submodule to calculate the friction velocity and Monin Obukov length, needed for aerodynamic resistance calculation. • Effects of moisture on stomatal resistance (3 vegetative states for each cell <--> surface resistance) • Deposition to water surfaces : can be rapid for many soluble gases (Henry’s Law Slinn & all 1978) • Effects of surface moisture : the extent of dew is estimated & rain-wetted ground • Wet Deposition : • Optional, used if rainfall, no interaction with cloud.

  8. Model configuration , Boundary configuration & Emission • Model configuration : • classical domain, resolution 3*3 km (and optionally 1*1 km ), 13 layers for chemistry • Boundary configuration • no nesting • forcing with large model - interpolation hour per hour in each boundary cell • EMISSION only use of Escompte emission files • main adjustment : • transposition of VOC emission in CB-V species. • No CH4 consumption • Point sources : used of all information

  9. Meteorology modelRAMS • Regional Atmopsheric Modelling System developped by MRC/Aster and now ATMET (since 1970) • Scientific community approved • Use by NUMTECH since 1996 • Comparisons with measurements : • ESCOMPTE : Pre-campaign 1999 and POI 2000 • Berre pond : sea breaze recirculations • Other studies : Lyon, Clermont-Ferrand, Atlantic coast, …

  10. Model configurationgrid resolution • 3 nested grids • G1 : 50*34*37 , Dx = Dy = 36 km , Dt = 50 s • G2 : 94*86*37 , Dx = Dy = 9 km , Dt = 25 s • G3 : 65*65*51 , Dx = Dy = 3 km , Dt = 8.33 s • Vertical levels G3 : Dz1 = 12 m , top = 18 km • Surface initialization • Topography : DEM 30’ , Landuse : USGS 30’ • Soil : USGS 30’ , NDVI : USGS 30’ , Satellite SST • Data assimilation • Grid data ECMWF (0.5°) • Observations : surface stations + rawinsoundings

  11. Comparison, aerosol, etc ... • Comparison : • nothing done for AQ • Aerosol • one species (PM), not use • Model Strengths / weakness • ? Carbon Bond : old but pragmatic approach • + Plume in Grid treatment

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