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Tropospheric model evaluation - an update

Tropospheric model evaluation - an update. Jennifer A. Logan Harvard University. Concerns raised at last Science Team meeting. Why are the GISS results so different, especially in the tropics? Is there still an implementation problem.

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Tropospheric model evaluation - an update

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  1. Tropospheric model evaluation - an update Jennifer A. Logan Harvard University

  2. Concerns raised at last Science Team meeting • Why are the GISS results so different, especially in the tropics? Is there still an implementation problem. • Dan found that most of the source of NOx from lightning was being emitted into the stratosphere. • Are the results with DAO met. products consistent with those obtained with GEOS-CHEM with the same met. fields? --------------------------------------------------------------------------- • Last topic - use of MOZAIC data for model evaluation

  3. Tropical ozone increased, with higher NOx CCM3 DAO GISS Old results New results

  4. Mid-latitude summer ozone increased (by much less) CCM3 DAO GISS New results Old results

  5. Ozone bias at the seasonal maximum and minimum Summary of problems with seasonality, vertical gradient, spatial patterns GISS is no longer an outlier

  6. Cumulative PDFs for O3 Problems related to stratospheric input

  7. Are we comparing apples and oranges?Interannual variability in data, one year of model results with monthly mean emissions

  8. Differences in CO - GISS results lower in the tropics (higher OH) Old results New results

  9. Cumulative PDFs of CO - examples

  10. Comparison of GMI/DAO with GEOS-CHEM The objective was to see if the GEOS-CHEM (GC) run that most resembled the GMI/DAO run gave similar results. The available GC run was for Sept. 96 - Aug. 97, Randall Martin’s base-case simulation that was compared to runs with the full effects of aerosols on chemistry and photolysis rates. • GMI - sulfate aerosols only • GC - 5 types of aerosols, of which dust is the most important (Martin et al., 2003). • BB sources different (GC=400, GMI = 460 Tg for CO) • SYNOZ flux different (GC = 475, GMI = 520 Tg) • Emissions input into mixed layer in GC, not in GMI

  11. CO: results very similar except over cont. sites

  12. Ozone: DAO (green) consistently higher than GC at 500, 300 hPa. Not just the effect of larger SYNOZ flux

  13. Results more similar in tropics and S. mid-lat.likely caused by effects of N2O5 + H2O on aerosols, with dust being most important

  14. HNO3 - often major differences - differentwet removal

  15. Effects of increased vertical mixing in PBL - sensitivity run by Dan. Huge decreases in CO over land sites.

  16. MOZAIC tropical ozone data now available for model evaluation

  17. Mozaic CO data/ GEOS-CHEM model Data released only up to Feb.03, and several months missing in 2002.Holds promise for evaluating vertical mixing.CO/O3 ratios can be checked out

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