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TR AZOMOZA IC Comparison in the UTLS

TR AZOMOZA IC Comparison in the UTLS. Andreas Volz-Thomas and Martin G. Schultz. Uncertainties in the Global Tropospheric Ozone Budget. Objectives. Analyse observed and simulated trace gas concentrations relative to the tropopause

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TR AZOMOZA IC Comparison in the UTLS

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  1. TRAZOMOZAICComparison in the UTLS Andreas Volz-Thomas and Martin G. Schultz

  2. Uncertainties in the GlobalTropospheric Ozone Budget

  3. Objectives • Analyse observed and simulated trace gas concentrations relative to the tropopause • Analyse observed and simulated variability: seasonal pattern and interannual variability • Focus on Northern Mid-latitudes AIM: • identify model errors and the underlying cause (transport or chemistry?) • identify the bias in the MOZAIC data

  4. Data selection for MOZART • Simulations 1993-1998, 6-hourly „instantaneous“ values (20min time step) • European MOZAIC airports and surrounding columns (1.8° resolution); duplicate boxes removed • Latitude range 43°N-60°N (ozone similar within ±5 ppb) • Model results selected on model levels relative totropopause (dT/dz<2k/km)

  5. Data selection for MOZAIC O3: 8/94–6/03 (five A-340), NOy and CO since 2001. TP selection: 2 pvu Level thickness from MOZART TP: (p(PV=2) - 15 hPa) > p > (p(PV=2) - 15 hPa) T+1 (LS): (p(PV=2) - 15 hPa) > p > (p(PV=2) - 45 hPa) T-1 (UT): (p(PV=2) + 45 hPa) > p > (p(PV=2) + 15 hPa)

  6. Results: Ozone MOZART MOZAIC

  7. LS: ca. 100 ppb TP: ca. 100 ppb UT: ca. 50 ppb Sesonal Variation of Ozone MOZAIC MOZART

  8. Ozone Correlations

  9. Results: NOy MOZART MOZAIC

  10. Seasonal Variation of NOy MOZAIC MOZART

  11. NOy Correlation

  12. Lower Stratospheric NOy/O3

  13. Sampling Bias in MOZAIC ?(p > 200 hPa)

  14. MOZART with Sampling Bias of MOZAIC: UT: 6+-6 ppb TP: 19+-10 ppb LS: 32+-14 ppb

  15. Conclusions • MOZART reproduces the seasonal pattern of ozone well. • Some features of interannual variability are captured, but several features are missing: emissions (e.g. 1998), varying stratospheric ozone as main explanation. • It has a bias of about +50 ppb in UT and +100 ppb in LS • The sampling bias in MOZAIC (6 ppb in UT and 32 ppb in LS) explains about 20-30 % of the discrepancy. • The seasonal cycle of NOy in LS is anticorrelated with observations (erroneous strat. climatology!) and has a weaker seasonal amplitude. Wrong NOy/O3 ratio in LS. • Hypothesis: STE too weak(!) in MOZART 2, balanced by LS ozone bias. Chemistry also too weak?

  16. Outlook • Tests with "better" NOy climatology and lower O3 in LS • Test for TP selection (use PV for MOZART as well) • Look at MOZAIC CO as well • Same analysis for other areas • ...

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