Ensemble Climate-Chemistry simulations for the past 40 years

1. Ensemble Climate-Chemistry simulations for the past 40 years Volker Grewe and the DLR/MPI Team Martin Dameris, Veronika Eyring, Fabian Mager, Michael Ponater, Tina Schnadt, Andrea Stenke - DLR Oberpfaffenhofen Benedikt Steil, Christoph Brühl, Patrick Jöckel - MPI- Mainz Marco Giorgetta, Claudia Timmreck, MPI-Hamburg Institut für Physik der Atmophäre DLR-Oberpfaffenhofen Germany Volker.Grewe@dlr.de

2. E39/C Climate-Chemistry Model • ECHAM4.L39(DLR) = E39 Atmosphere circulation model • Global spectral model with semi-Lagrangian advection of water vapour, cloud water and tracers • Resolution: T30, 39 layers, top layer centered at 10 hPa (30 km) • Parameterizations of radiation, clouds, precipitation, convection, diffusion • CHEM = C Chemistry-Module (family concept) • Transported species: H2O, CH4, N2O, HCl, H2O2, CO, CH3O2H, ClONO2, HNO3+NAT, ICE, ClOx, NOX, OX • 37 species and 107 gas-phase reaction • Methane oxidation, PSC formation, 4 heterogeneous reactions on PSCs • Parameterization of dry/wet deposition, lightning and surface emissions • Interactively coupled at every timestep

3. Coupling of Dyamics and Chemsitry in E39/C

4. Simulation of the Earth‘s atmosphere from 1960 to 2000 • Simulation is based on climate chemistry model E39/C with additional forcings: • Emissions of NOx, CO, CO2, N2O, CH4, CFCs, as observed or estimatd by IPCC • QBO nudged in tropical stratosphere • Volcanoes regarded (Agung, El Chichon, Pinatubo) for chemistry and radiation • Observed sea surface temperatures (Hadley-GISS) • 11 year solar cycle • No other forcing, free running climate chemistry model

5. Total Ozone [DU] • High variability • > than in time-slices • Solar cycle in tropics • Ozone hole starts 80s • Global ozone -15 DU

6. Tropospheric ozone column (DU) • High variability • Global increase: 4 DU • Small effects on SH

7. El Nino events Simulated evolution of cloud to ground lightning 1960 to 2000

8. Ensemble 50 hPa temperature

9. Ensemble total ozone

10. Ensemble tropospheric total ozone

11. Lightning

12. Summary • CCM/CTM Models are ready for transient simulations • ACCENT modelling acitivity: Ensemble simulations • Capability of models (-> Comparison to measurements) • Attribution perhaps possible? • Tropospheric Ozone Column ? • Temperature BUT

13. Fully coupled CCM simulations require additional diagnostics in order • to separate various effects. • E.g. NOx and ozone tagging diagnostics

14. Approach: Tagging of NOy and ozone molecules 1st step: For each source i=1, ... , n (n=8) define a NOy tracer (Xi) 2nd step: For each NOy tracer define an ozone tracer (Yi) and an ozone tracer (Yn+1) for ozone production by O2 photolysis Attribution of ozone increase to NOx emissions

18. Ozone tracer mass 200-500 hPa 500-1000 hPa Tropical past ozone changes 30S-30N • Lightning most important • source for tropical ozone • In UT: stratospheric • intrusions also important

19. Interannual variability in the tropics Upper troposphere Lower troposphere • Solar cycle effects stratospheric ozone • leading to weak UT ozone variations (5%) • Stratospheric O3 and lightning important • for inter-annual variations • Industry and land transportation • responsible for trends