Simulating the atmospheric composition during the last decades: Evaluation with long-term observational datasets and the impact of natural climate variability Volker Grewe, Martin Dameris, Jens Grenzhäuser and Pieter Valks German Aerospace Center ACCENT-GLOREAM, Paris, October, 2006
Institut für Physik der Atmosphäre Institutstag IPA 2006 Transport and Chemistry NOx - Ozon Production Ozone Production (Chapman ) Ozone Intrusion ENSO Solar Cycle Air Quality Emissions
Institut für Physik der Atmosphäre Institutstag IPA 2006 CCM E39/C (Stratosphere-troposphere)- Model description Surface, aircraft, lightning NO x Emissions [Tg N/a] Radiation Long-wave Short-wave Chemical Boundary Conditions Atmosphere: CFCs, at 10 hPa: ClX, NO y, Surface: CH 4, CO Chemistry (CHEM) Methane oxidation Heterogeneous Cl reactions PSC I, II, aerosols Dry/wet deposition Photolysis Feedback O 3, H 2 O, CH 4, N 2 O, CFCs Prognostic variables (vorticity, divergence, temperature, specific humidity, log-surface pressure, cloud water), hydrological cycle, diffusion, gravity wave drag, transport of tracers, soil model, boundary layer; sea surface temperatures. T30, 39 layers, top layer centred at 10 hPa Dynamics (ECHAM) Hein et al., 2001
Institut für Physik der Atmosphäre Institutstag IPA 2006 Transiente Model simulation - Boundary Conditions QBO Solar cycle and volcanoes Dameris et al., 2005
Institut für Physik der Atmosphäre Institutstag IPA 2006 Transiente Model simulation - Boundary Conditions Natural und anthropogenic NO x emissions: SourceReference Emissions: 1960 to 2000 IndustryBenkovitz et al., TgN/a Lightning Grewe et al., 2001 ~5 TgN/a Air trafficSchmitt und Brunner, TgN/a Surface Traffic Matthes, TgN/a ShipsCorbett et al, TgN/a Biomass BurningLee, pers. comm TgN/a Sea surface temperatures and ice coverage: Monthly means: UK Met Office Hadley Centre, hier: Beispiel für Juni 1985 (Rayner et al., 2003)
Institut für Physik der Atmosphäre Institutstag IPA 2006 Evolution of ozone column [DU]: Ozone hole High variability
Institut für Physik der Atmosphäre Institutstag IPA 2006 De-seasonalized anomalies of the ozone columns [%] QBO clearly visible Global Trend: ~20 DU y- Solar cycle recognizable, but QBO, volcanoes, trend overlaid
Institut für Physik der Atmosphäre Institutstag IPA 2006 E39/C vs. Observation: Anomalies of ozone column E39/C TOMS Ground stations (Bojkov and Fioletov, 1995; pers. com. Fioletov, 2004) calm, stable winter situations Beginning of 90s: stronger ozone losses Individual strong events well represented
Institut für Physik der Atmosphäre Validation of E39C results: Tropospheric Ozone Mean annual cycle of ozone at 47°N, 11°E ( ) E39C OBS E39C minus OBS Hohenpeißenberg Too weak seasonal cycle Cold bias too = high tropopause
Institut für Physik der Atmosphäre Validation of E39C results Mean annual cycle of ozone at 40°N, 105°W ( ) E39C OBS E39C minus OBS Boulder Similar conclusion
Institut für Physik der Atmosphäre Validation of E39C results 47°N, 11°E; 300 hPa 47°N, 11°E; 500 hPa 47°N, 11°E; 700 hPa 47°N, 11°E; 850 hPa Ozonesonde E39C Ozonesonde E39C Ozonesonde E39C Ozonesonde E39C Evolution of ozone anomalies at distinct levels [in ppbv] Hohenpeißenberg Variability smaller: Sampling or real difference ? Evolution not well reproduced: - very rough assumptions on emission data - no interannual variability of bb emissions
Institut für Physik der Atmosphäre Validation of E39C results 47°N, 11°E; 500 hPa Ozonesonde E39C Evolution of ozone anomalies [in ppbv] Some agreement: Coincidience or period where changes are controll by processes, which are better described
Institut für Physik der Atmosphäre April Average tropospheric tropiocal O 3 -Column below 200 hPa July October Januar 180°W 20°N Eq. 180°E 20°S Generally higher ozone values ! General pattern in agreement: Minimum over Pacific Maximum over Africa GOME (TEMIS)E39/C However, ozone maximum less pronounced: Biomass burning?
Institut für Physik der Atmosphäre Average tropospheric tropiocal O 3 -Column below 200 hPa Generally higher ozone values ! General pattern in agreement: Minimum over Pacific Maximum over Africa GOME (TEMIS)E39/C However, ozone maximum less pronounced: Biomass burning? 180°W 20°N Eq. 180°E 20°S MAM DJF JJA SON DU DU Minimum South America Maximum Africa Minimum Pacific
Institut für Physik der Atmosphäre How can we understand the simulated trends and the observed differences ? - Sensitivity studies (for selected periods) e.g. rerun period without volcanic eruption (Pinatubo) - Additional diagnostics Tracer: Ozone origin (Regions in Stratosphere/ Troposphere) Tracer: Ozone 'source') (biomass burning, Lightning,...) Mass fluxes
Institut für Physik der Atmosphäre Institutstag IPA 2006 Simulated ozone origin Grewe, 2006
Institut für Physik der Atmosphäre Institutstag IPA 2006 Grewe, 2004
Institut für Physik der Atmosphäre Institutstag IPA 2006 Ozone influx from the stratosphere to the troposphere De-seasonalized Monthly means x Estimate based on correlations with long-lived species: 475 Tg/year (Murphey and Fahey, 1994) and with flux calculations: NH: 252 Tg/a SH: 248 Tg/a (Olson et al., 2004) Signal of solar cycle identifyable especially on SH Large interannual variability No trends recognizable
Institut für Physik der Atmosphäre Institutstag IPA 2006 De-seasonalized ozone changes in the tropical UT Stratospheric ozone follows influx from stratosphere, producing ±2% variability out of a totale interannual var. of ±4% Lightning ozone correlated with Nino Index variability: ±1-2%
Institut für Physik der Atmosphäre Institutstag IPA 2006 Evolution of de-seasonalized ozone in NH lower troposphere (30N-90N; hPa) Year-to-year variability strongly dominated by stratosphere (±5%) Trend in ozone (25% increase): - results from increase in NO x emissions (Industry and traffic) - Trend reduction in 80s caused by lower emissions and lower stratospheric contribution. ~25% ~30% -5%
Institut für Physik der Atmosphäre Conclusions - Outlook (I) Stratosphere well reproduced Troposphere: Some similarities with observational data Main Discrepancies: Too weak seasonal cycle: - Too strong influence from stratosphere (chem lifetime) - Too much transport of upper troposphere tropical air - Too weak seasonal cycle of O 3 perturbation from anthropogenic emissions Less intense tropical ozone maximum Solution: Rerun with revised emission data (RETRO) biomass burning + anthrop. emission data including interannual and regional variability
Institut für Physik der Atmosphäre Conclusions - Outlook (II) Discrepancies: Less ozone in the upper troposphere: - Problem of cold bias = too high tropopause Solution: Lagrangian transport scheme Realistic water vapor transport 80% Reduction of Cold Bias (Stenke&Grewe, 2006) Despite discrepancies Stratospheric ozone variability influences trend (Trend reduction in 80s) Impact of stratospheric and tropospheric variability (El Nino) quantified.
Institut für Physik der Atmosphäre
Institut für Physik der Atmosphäre Future outlook adopted from Fishman et al., 2003
Institut für Physik der Atmosphäre JanFebMar AprMayJun JulAug Dec Sep NovOct GOME (CCD): Average O 3 -Column below 200 hPa °W 20°N Eq. 180°E 20°S
Institut für Physik der Atmosphäre E39C : Average tropospheric O 3 -column JanFebMar AprMayJun JulAug Dec Sep NovOct 20°N Eq. 180°W180°E 20°S
Institut für Physik der Atmosphäre Institutstag IPA 2006 Total cloud cover from the transient run of the ECHAM model in comparison to ISCCP, ECC, and SYNOP data sets ECC, ~11:30-16:30 UT ISCCP-D2, 12:00 UT SYNOP, 12:00 UT ECHAM, 24h Monthly means, area averaged d=+12% c=0.2 d=-16% c=0.7 d=0.0% c=0.4 R. Meerkötter, V. Grewe, M.Dameris, M. Ponater; (DLR-IPA), H. Mannstein (DLR-IPA), G. Gesell (DLR-DFD), C.König (DLR-IPA) Meerkötter et al., 2004
Institut für Physik der Atmosphäre Validation of E39C results Mean annual cycle of ozone at 13°S, 171°W ( ) E39C OBS E39C minus OBS Samoa
Institut für Physik der Atmosphäre Validation of E39C results Mean annual cycle of ozone at 70°S, 8°W ( ) E39C OBS E39C minus OBS Neumayer
Institut für Physik der Atmosphäre Validation of E39C results 47°N, 11°E; 500 hPa Ozonesonde E39C Ozonesonde E39C 40°N, 105°W; 500 hPa Evolution of ozone anomalies at distinct stations [in ppbv] Hohenpeißenberg Boulder
Institut für Physik der Atmosphäre Institutstag IPA 2006 Ozone influx: ozone origin Northern Hemisphere: Ozone mainly produced in NHMS TRMS TRTS NHMS: high inter-annual variability Southern Hemisphere: Ozone mainly produced in TRTS SHMS TRLS SHMS low inter-annual variability solar cycle visible Grewe, 2005