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Transboundary Modelling of Particulate Matter with REMOTE- Saji Varghese, NUIG


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Presentation from EPA Transboundary Research Workshop, Galway, 8th and 9th September 2010.

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Transboundary Modelling of Particulate Matter with REMOTE- Saji Varghese, NUIG

  1. 1. Transboundary Modelling of Particulate Matter with REMOTE <br />Saji Varghese<br />Centre for Climate and Air Pollution Studies and School of Physics, National University of Ireland, Galway<br />
  2. 2. Motivation<br />Impact on human health<br />Aerosols contribute to climate change<br />Tool for researchers and policy-makers<br />Different models<br /><ul><li>Dispersion models
  3. 3. Chemistry transport models (CTMs)
  4. 4. Regional climate models (RCMs) coupled with aerosol dynamics and chemistry</li></li></ul><li>REMOTE<br /><ul><li>Regional Model with Tracer Extension (Langmann, 2000)</li></ul>-The three-dimensional high resolution regional climate model<br />-Hydrostatic model<br />-Arakawa-C grid is used for the prognostic equations.<br />-Driven by ECMWF analysis data every 6 hours at lower and<br /> lateral boundaries<br />- Dynamics is based on the regional weather forecast model<br /> system of the German Weather Service while physical <br /> parameterizations are based on the ECHAM4 model.<br /><ul><li>Aerosol dynamics is based on the modal aerosol model M7.</li></ul>- Includes RADM2 chemistry<br />
  5. 5. Microphysical aerosol module M7<br />Vignati et al., JGR (2004), Stier et al., ACP (2005)<br />- aerosol size distribution in 7 log-normal modes<br /><ul><li>determination of the chemical composition</li></ul>Sulfate<br />Black Carbon<br />Organic Carbon<br />Sea salt<br />Mineral dust<br />
  6. 6. RADM2 chemistry<br />163 reactions, 63 species (Stockwell et al., 1990)<br />Stiff ODE’s describe the gas phase chemistry and uses operator splitting approach<br />Model Set-up<br /><ul><li>Horizontal resolution - 0.5o(~50 km) - 81x91 grid points,
  7. 7. Vertical levels - 19
  8. 8. Time step - 5 min
  9. 9. Domain - Western Europe and North East Atlantic
  10. 10. Emission - EMEP and organic-inorganic source function
  11. 11. Chlorophyll data - MODIS satellite </li></li></ul><li>Correlate organic carbon fraction as a function of grid box average chlorophyll<br />Calculate seasonal accumulation mode & WIOC/Sea-salt ratio (Yoon et al.,2007)<br />Assume internal mixing between organic and sea-salt<br />Calculate wind speed related number flux (Geever et al., 2005) for accumulation mode<br />Combined Organic and Inorganic Sea-Spray Source Function <br />(O’Dowd et al., 2008)<br />Result: combined sea-spray source function including organic matter<br />
  12. 12.
  13. 13. Secondary Organic Aerosol (SOA) in the Marine Environment (Antilla et al., 2010)<br />Isoprene source function<br />Isoprene concentration in sea water is proportional to chlorophyll-a concentration (Meskhidze and Nenes, 2006)<br />Isoprene flux =product of isoprene concentration and gas exchange coefficient (Palmer and Shaw, 2005)<br />isoprene oxidation products as major SOA precursors<br />SOA formation based on Henry’s law<br />
  14. 14. SOA: Six additional components in M7<br />- isoprene oxidation products as SOA precursors<br />- SOA formation based on Henry’s law<br />
  15. 15. Ozone Concentration-sensitivity to deposition <br />schemes (Coleman et al., 2010)<br /><ul><li>Fairall’s deposition scheme vs Wesley scheme</li></li></ul><li>Resolution sensitivity study<br /> (Varghese et al.,2010, under review)<br />Black carbon<br />Sulphate<br />
  16. 16. Eyjafyalla volcano eruption<br />April-May 2010<br />disruption to air-traffic<br />Economic losses to airlines, insurance companies, logistics operations, tourism industry<br />Initial forecasts from VAAC – using NAME model<br /> - 4mg/m3 limit<br /> - 2mg/m3 limit<br /> - Forecasting with REMOTE – an additional tool<br /> - air-quality<br />
  17. 17. Development of volcanic ash forecasting system<br />boundary data preparation from ECMWF forecast data and analysis<br />model development and source term parameterisation<br />volcano source data gathering and assimilation<br />comparison with other dispersion models<br />continual refinement of the model for improving forecasts<br />forecasts issued twice daily<br />automation<br />
  18. 18. Key input parameters and associated uncertainties for models<br />Source term (key eruption parameters)<br />Mass flux<br />vertical distribution of mass<br />column height<br />particle size distribution<br />density<br />
  19. 19. Sample 4-day forecast <br />Spatial distribution of volcanic ash (mg/m2)<br />Horizontal resolution: <br />0.5o(~50 km), 81x91 grid points <br />Vertical levels : 19<br />Time step: 5 min<br />Boundary data: ECMWF forecast<br />Emission source: Iceland Met office<br />
  20. 20. Volcano ash forecasting system<br />
  21. 21. Comparison of REMOTE model output with NAME results<br />
  22. 22. Sensitivity tests – (i) Spatial distribution<br />
  23. 23. (ii) Vertical distribution <br />
  24. 24. Conclusions<br />state-of-the art modelling system to determine atmospheric chemical composition <br />an integrated air-quality forecast system will be developed and evaluated<br />a useful research tool to study implication of climate change on air-quality<br />
  25. 25. Acknowledgements<br />Met Eireann<br />ICHEC<br />Modelling Team (NUI Galway) - Damien Martin, Robert Flanagan, Liz Coleman and Colin O’Dowd<br />BaerbelLangmann (Univ. of Hamburg) and TatuAntilla (FMI, Helsinki) <br /> EPA<br />