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Impact of Emission Schemes on Online Air Quality Modelling

Impact of Emission Schemes on Online Air Quality Modelling. WWOSC – Montreal – August 2014 Carlos Ordóñez, Mohit Dalvi, Nick Savage, Paul Agnew, Lucy Davis, Marie Tilbee. Impact of Emission Schemes on Online Air Quality Modelling. Introduction of AQUM Representation of emissions in AQUM

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Impact of Emission Schemes on Online Air Quality Modelling

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  1. Impact of Emission Schemes on Online Air Quality Modelling WWOSC – Montreal – August 2014 Carlos Ordóñez, Mohit Dalvi, Nick Savage, Paul Agnew, Lucy Davis, Marie Tilbee

  2. Impact of Emission Schemes on Online Air Quality Modelling • Introduction of AQUM • Representation of emissions in AQUM • Vertical and temporal profiles of emissions • Results • Summary and outlook

  3. 1. Introduction

  4. Air Quality in the Unified Model (AQUM) • Limited area configuration of the Unified Model (UM) used for AQ forecast • 12 km horizontal resolution & 38 model levels (surface-39km) • On-line model: chemistry & aerosol processes fully coupled to meteorology • 5-day operational AQ forecast for the UK with: • Meteorological LBCs from UM global run • Chemical LBCs from MACC global forecast • Also run in hindcast mode (chemical LBCs from MACC & GEMS reanalyses, …)

  5. Chemistry and aerosol processes (I) • Chemistry processes represented within the United Kingdom Chemistry and Aerosols (UKCA) sub-model of the UM. • UKCA initially developed for climate-chemistry studies at the global scale. A number of chemistry schemes available. • Regional Air Quality (RAQ) chemistry scheme implemented to introduce more complex reactive organic chemistry: • oxidation of C4 alkanes (butane), C2-C3 alkenes (ethene and propene), and aromatic compounds (toluene and o-xylene) • Main features of RAQ • Adapted from STOCHEM [Collins et al., 1997, 1999] • 40 transported species (16 emitted) + 18 non-advected • 116 gas-phase reactions + 23 photolysis reactions • Dry deposition for 16 species + wet dep. for 19 species

  6. Chemistry and aerosol processes (II) • CLASSIC aerosol scheme (another UM sub-model, not part of UKCA) • SO2 & ammonium sulphate • Ammonium nitrate • Black carbon • Fossil fuel organic carbon (FFOC) • Biomass burning aerosol • Climatology of biogenic secondary organic aerosols (BSOA) • Online emissions of dust & sea-salt • Calculation of PM2.5 & PM10concs • More details or RAQ chemistry and aerosol processes in AQUM: Savage et al. [GMD, 2013] Coupled to UKCA oxidants • Future: Use of GLOMAP-mode aerosol scheme. Full coupling between chemistry & aerosols in UKCA • Details on CLASSIC & GLOMAP-mode: Bellouin et al. [JGR, 2011; ACP, 2013]

  7. 2. Representation of emissions in AQUM

  8. Generation of emissions Generated by merging all source sectors from datasets at different resolution: NAEI, EMEP/MACC & ENTEC NAEI @ 1km ENTEC shipping @ 5km EMEP @ 50km (more recently 5 km MACC dataset, valid for 2003-2009)

  9. Generation of emissions Generated by merging all source sectors from datasets at different resolution: NAEI, EMEP/MACC & ENTEC NAEI @ 1km ENTEC shipping @ 5km EMEP @ 50km (more recently 5 km MACC dataset, valid for 2003-2009)

  10. Current treatment of emission in AQUM Emissions of gas phase species (in UKCA) • Monthly varying emission files: • 2-D “surface” emissions of NOx, CO & 14 VOCs (inc. biog C5H8) • 3-D field for NOx from aircraft • All anthropogenic source sectors merged • Simplistic vertical profiles and temporal emission factors Aerosol emissions (in CLASSIC) • Combination of monthly 2-D (low-level and high-level) and 3-D fields • Online emissions of dust and sea-salt • See details in Savage et al. [GMD, 2013] UKCA and CLASSIC initially developed for climate-chemistry-aerosol studies at the global scale. The representation of emissions lacks the flexibility needed for regional AQ modelling.

  11. New emission scheme • New emission system for gas phase emissions in UKCA: • Independent monthly emission fields for each source sector • They can be injected at different altitudes and with different temporal variability • Aerosol emissions remain unchanged because CLASSIC will be retired. Future: extend the new system to aerosol emissions in UKCA.

  12. 3. Vertical and temporal profiles of emissions

  13. Vertical disaggregation of emissions • Three types of vertical profiles tested for antropogenic emissions: • step1 (current system): Emissions injected in three lowest model levels: 80% (20 m mid-layer), 15% (80 m) & 5% (180 m) • EMEP: Profiles based on those from EMEP model [Simpson et al., ACP, 2012] • Bieser:Based on calculations with SMOKE-EU plume-rise model[Bieser et al., Env. Pollut., 2011] Vertical disaggregation for SNAP sectors 1–10 Injection heights: EMEP > Bieser > step1

  14. Temporal emission factors Hourly & daily factors needed to account for daily and weekly variability in emissions. Implemented using two sources: • traffic-UK (current system): Factors based on traffic UK data applied to all anthropogenic emissions • TNO-MACC: Derived by TNO for the MACC project [Denier van der Gon et al., 2011] Hourly factors traffic-UK non-traffic

  15. Temporal emission factors Hourly & daily factors needed to account for daily and weekly variability in emissions. Implemented using two sources: • traffic-UK (current system): Factors based on traffic UK data applied to all anthropogenic emissions • TNO-MACC: Derived by TNO for the MACC project [Denier van der Gon et al., 2011] Daily factors traffic-UK traffic (TNO-MACC) non-traffic (TNO-MACC)

  16. 4. Results

  17. Summary of emission profiles tested • Vertical profiles • EMEP, Bieser & step1 (EMEP & Bieser evaluated by Mailler et al. [ACP, 2013]) • Temporal factors • traffic-UK: unreasonable bimodal diurnal cycle • TNO-MACC: more realistic

  18. Summary of emission profiles tested • Vertical profiles • EMEP, Bieser & step1 (EMEP & Bieser evaluated by Mailler et al. [ACP, 2013]) • Temporal factors • traffic-UK: unreasonable bimodal diurnal cycle • TNO-MACC: more realistic We show results (mainly summer 2006/2013) for: operational effective emission height Comparison with AURN surface observations (> 50 sites)

  19. NOx & O3 (June – July 2006) LBCs from GEMS reanalysis

  20. NOx & O3 (June – July 2006) LBCs from GEMS reanalysis

  21. NOx & O3 (June – July 2006) LBCs from GEMS reanalysis

  22. NOx & O3 (June – July 2006) LBCs from GEMS reanalysis

  23. NOx & O3 (June – July 2006) LBCs from GEMS reanalysis AURN observations (> 50 sites)

  24. O3 (June – July 2006) LBCs from GEMS reanalysis CTRL Bieser-TNO EMEP-TNO FGE 0.35 0.33 0.32 MNMB -0.03 -0.030.01 R 0.700.73 0.73 Stdev ratio 0.910.93 0.92 fac2 0.86 0.88 0.89

  25. FGE 0.360.350.36 MNMB 0.19 0.20 0.22 R 0.650.67 0.67 Stdev ratio 0.970.98 0.98 fac2 0.860.87 0.87 O3 (operational: Jul – Aug 2013) LBCs from MACC global forecast CTRL Bieser-TNO EMEP-TNO

  26. Diurnal cycles of bias/RMSE (Jun–Jul 2006) CTRL Bieser-TNO EMEP-TNO NO NO2 O3 Bias (µg m-3) 0 6 12 18 23 0 6 12 18 23 0 6 12 18 23 RMSE (µg m-3) 0 6 12 18 23 0 6 12 18 23 0 6 12 18 23

  27. JA 2013 Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Weekly cycles of RMSE (µg m-3) CTRL Bieser-TNO EMEP-TNO NO NO2 O3 JJ 2006 Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun

  28. Minor impact on PM

  29. 5. Summary and outlook

  30. Summary and outlook (I) • A new emission scheme (initially only for gas phase species) implemented • Flexibility: • Can handle emissions independently according to source sector • Allows the use of realistic vertical and temporal profiles • Bieser vertical profiles and TNO-MACC temporal factors adopted for operational implementation in AQUM • However minor impact on model results for NOx and O3 • Other processes in the model (e.g. chemical LBCs, dry deposition, chemistry) may have a stronger impact on O3

  31. Summary and outlook (II) • CLASSIC aerosols  GLOMAP-mode aerosols (UKCA). Extend new emission system for aerosols • Interactive emission fluxes of biogenic VOCs from JULES (land surface model) in UKCA  Impact on isoprene and O3 • Development of an AQUM configuration at 4 km x 4 km (70L)  Test vertical emission profiles

  32. Vertical disaggregation of emissions • Three types of vertical profiles tested for antropogenic emissions: • Step1 (current system): Emissions injected in three lowest model levels: 80% (20 m mid-layer), 15% (80 m) & 5% (180 m) • EMEP: Profiles based on those from EMEP model [Simpson et al., ACP, 2012] • Bieser:Based on calculations with SMOKE-EU plume-rise model[Bieser et al., Env. Pollut., 2011] Vertical disaggregation for SNAP sectors 1–10 Weighted avg. for NOx, CO and NMVOCs Injection heights: EMEP > Bieser > step1

  33. Operationally: LBCs from MACC global forecast at ECMWF Hindcast: LBCs from MACC & GEMS reanalyses [Savage et al., GMD, 2013] CHIMERE Observations [Schere et al., AE, 2012]

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