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Chemical Weather with GEM-AQ

Chemical Weather with GEM-AQ. Model Evaluation – five year global simulation. Jacek W. Kaminski Joanna Struzewska Lori Neary Alex Lupu Jonh C. McConnell Atmospheric Modelling and Data Assimilation Laboratory Centre for Research in Earth and Space Science York University. Supported by

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Chemical Weather with GEM-AQ

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  1. Chemical Weather with GEM-AQ Model Evaluation – five year global simulation Jacek W. Kaminski Joanna Struzewska Lori Neary Alex Lupu Jonh C. McConnell Atmospheric Modelling and Data Assimilation Laboratory Centre for Research in Earth and Space Science York University

  2. Supported by • Canadian Foundation for Climate and Atmospheric Sciences • Environment Canada • Natural Science and Engineering Research Council of Canada • Canadian Foundation for Innovation • Canadian Space Agency • Transport Canada Paris, October 11, 2006

  3. Objectives • Test the robustness of the model • Examine seasonal variations and regional distributions of ozone and other species • Investigate processes in the model to see where improvements may be necessary • Prepare initial conditions for high resolution runs Paris, October 11, 2006

  4. GEM model • Global Environmental Multiscale model (Côté at al.1998) • Operational execution on 0.9ox0.9o global grid • 4D-VAR continuous objective analysis • 5 and 10 day weather forecasts – global • 48 hour regional forecast over North America ~15km • Vertical resolution 58 hybrid levels • Top at 10 mb • Coupled with comprehensive physics • GEM-strato • research version with model top at 0.1 mb • air quality, tropopospheric and stratospheric chemistry • Meso-Global - ~35km resolution Paris, October 11, 2006

  5. GEM – dynamical core • Two time level semi-Lagrangian advection semi-implicit scheme • Variable-resolution on an Arakawa C grid in the horizontal with second order accuracy • Many grid configurations are possible Global variable Global uniform Limited area Paris, October 11, 2006

  6. sigma hybrid GEM dynamical core • Non-staggered finite differences in the vertical with second order accuracy • hybrid vertical coordinate(GEM V3.0 and higher) : Paris, October 11, 2006

  7. GEM-AQ Modules • on-line implementation • Tracer transport • Tracer convection • Tracer vertical diffusion • Gas phase chemistry • Trop. 50 species, ~130 reactions • Trop+strat 75 species, ~200 rections • Photodissociation rates (J values from Messy) • Wet chemistry • Aerosol chemistry and physics • 5 size-resolved aerosol types – 12 bins each – 60 tracers • Biogenic emissions • Lightning NOx emissions Paris, October 11, 2006

  8. Simulation Description • Five year simulation (2001-2005) • Results shown are global uniform resolution at 4x4 and 1.5x1.5 degrees, 28 hybrid levels to 10 hPa Paris, October 11, 2006

  9. Comparison with Ozonesondes • Monthly and seasonal mean climatology compiled by Logan (1999), 35 stations • Northern hemisphere generally good agreement, some over-prediction in summer boundary layer • Tropical profiles could indicate a poor representation of deep convective transport • Most SH stations have an over-prediction in the 700-200 mb region, and an under-prediction in the upper troposphere Paris, October 11, 2006

  10. Station: Churchill (NH) DJF MAM SON JJA Paris, October 11, 2006

  11. Station: Natal (Tropics) DJF MAM SON JJA Paris, October 11, 2006

  12. Tropospheric Column O3 • Comparison with GOME shows over-prediction in SH • Results improve greatly with increase in horizontal resolution (1.5x1.5 degrees) October 2001 mean GOME, GEM, GOME-GEM Paris, October 11, 2006 Thanks to X. Liu, Harvard-Smithsonian Institute of Astrophysics for GOME data

  13. Tropospheric column NO2 • Comparison with SCIAMACHY shows some under-estimation, especially around China • Could indicate anthropogenic emissions used are too low in this region • Agreement is better over N. America and Europe Paris, October 11, 2006

  14. Tropospheric Column NO2 • July 2004 GEM (left) and GOME (right) Paris, October 11, 2006 Thanks to A. Richter, U. of Bremen for GOME data

  15. Aura-MLS vs GEM-AQ and GEOS-CHEM • Overall, GEM-AQ captures the dynamical features seen in the MLS CO data • At 100 and 150 hPa, the magnitude of the GEM-AQ CO agrees reasonably well, but at 200 hPa, the model under-predicts by about one half. This could indicate that the biomass burning emissions are too low, or that the CO is not being transported effectively up to the 200 hPa level by deep convection. • In some months (March for example), the biomass burning signature in Africa seen in the MLS data is not seen in the model. Paris, October 11, 2006

  16. March 2005 100 hPa • Missing biomass burning signature over Africa but magnitudes elsewhere in range Paris, October 11, 2006 Results for March 2005 at 100 hPa (top), July 2005 at 150 hPa (middle) and October 2005 at 200 hPa (bottom). Note the scales on the Aura-MLS, GEOS-CHEM and GEM-AQ plots are different.

  17. July 2005 150 hPa • Magnitudes and patterns agree between MLS and GEM-AQ Paris, October 11, 2006

  18. October 2005 200 hPa • Under-predict by a factor of 2 at this level Paris, October 11, 2006

  19. GEM-AQ vs MOPITT • The comparison with Aura-MLS data shows that the biomass burning emissions used in GEM-AQ are probably too low by a factor of 2 • The MOPITT total column CO seems to suggest this as well, but indicate that transport by deep convection may also be weak Paris, October 11, 2006

  20. GEM-AQ vs MOPITT GEM-AQ (left) total column CO compared with MOPITT (right) for Februrary 2004 GEM-AQ (left) total column CO compared with MOPITT (right) for August 2004 Units: molec./cm2 Paris, October 11, 2006

  21. GEM-AQ vs MOPITT • GEM-AQ under-predicts CO amounts by a factor of 2 around 200 hPa • The large scale dynamical features can be seen in both the models and the satellite measurements • New emissions are being prepared based on fire counts. Once the improvements to emissions have been done, further analysis of the deep convective transport parameterization used in GEM-AQ is needed. Paris, October 11, 2006

  22. Stratosphere-troposphere exchange at high latitudes Quantify the impact of both the vertical coordinate system and the horizontal resolution on the influx of ozone and STE in an on-line 3D global chemical weather model, GEM-AQ

  23. GEM vertical coordinates • GEM hybrid vertical coordinate system, where local pressure is: • When rcoef=1, system reverts to essentially sigma coordinates Paris, October 11, 2006

  24. Model Simulations • 3 global uniform resolution runs: • Horizontal 4x4 degrees, vertical coordinates using rcoef=1. • Horizontal 4x4 degrees, vertical coordinates using rcoef=1.6 (hybrid) • Horizontal 1.5x1.5 degrees, vertical coordinates using rcoef=1.6 (hybrid) Paris, October 11, 2006

  25. Ozone fluxes • To assess the ozone inflow, we examine the flux through one model level (with average pressure ~230 hPa) Paris, October 11, 2006

  26. Ozone fluxes • Based on observations, the influx of stratospheric O3 is estimated to be ~550 +/- 140 Tg/yr • Models analysed by Prather et al. (2001) have computed a range of 390-1440 Tg/yr Paris, October 11, 2006

  27. Ozone fluxes • Improving the resolution alone has a significant impact on the ozone flux and the use of a hybrid coordinate also reduces the flux. This can also be seen in the comparison with the GOME column ozone • With a top at 10 mb and a sponge layer reaching down to about to 50 mb, the circulation in the lower stratosphere will be impacted. Ultimately we need to remove the effect of the sponge; this is the case with a new research version of GEM, GEM-Strato with a lid at 0.1 mb. Paris, October 11, 2006

  28. Impact of horizontal resolution GOME GEM GOME-GEM 4x4 run Dec 2001 1.5x1.5 run Dec 2001 GOME data thanks to Xiong Liu (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA). Paris, October 11, 2006

  29. Yukon – Alaska fires, 2004 • To further understand and quantify the impacts of biomass burning and deep convective transport on the chemical constituents in the upper troposphere Paris, October 11, 2006

  30. Emissions • Monthly emissions from the Global Fire Emission Database version 2.0 • Distributed into hourly emissions according to the GOES-10 WF_ABBA fire pixel counts • Emission factors from Andreae and Merlet (2001) • Species emitted: CO, NO, CH3OH, HCOOH, C2H6, C2H4, C3H8, HCHO, CH3COOH, higher alkanes and alkenes, aromatics, toluene • No aerosol particles Paris, October 11, 2006

  31. GEM vs. ACE (1/3) Paris, October 11, 2006

  32. GEM vs. ACE (2/3)

  33. GEM vs. ACE (3/3) Paris, October 11, 2006

  34. Ongoing model evaluation • Urban • Pacific 2001 – Vancouver • ESCOMPTE – 2001 Marseilles • Krakow – 2005 • Regional • North America – surface ozone (PM2.5) • Brazil - TROCCINOX • Quebec fires 2002 • EU heat wave - 2006 Paris, October 11, 2006

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