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The Whole Atmosphere Community Climate Model: Overview, Current Research and Future Plans

The Whole Atmosphere Community Climate Model: Overview, Current Research and Future Plans. Rolando Garcia. Outline. WACCM overview Research with WACCM Solar cycle impacts 1950-2003 trend simulations 21 st century prognostic simulations Upper atmosphere dynamics (2-day wave)

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The Whole Atmosphere Community Climate Model: Overview, Current Research and Future Plans

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  1. The Whole Atmosphere Community Climate Model: Overview, Current Research and Future Plans Rolando Garcia

  2. Outline • WACCM overview • Research with WACCM • Solar cycle impacts • 1950-2003 trend simulations • 21st century prognostic simulations • Upper atmosphere dynamics (2-day wave) 3. Future work CCSM June 2006

  3. Acknowledgments… the following colleagues contributed to the work presented in this talk . . . • Doug Kinnison (ACD) • Dan Marsh (ACD) • Katja Matthes (Free University Berlin) • Astrid Maute (HAO) • Jadwiga Richter (CGD) • Fabrizio Sassi (CGD) • Stan Solomon (HAO) CCSM June 2006

  4. and, of course, Byron Boville … … to whose memory this talk is dedicated CCSM June 2006

  5. 1. Overview of WACCM CCSM June 2006

  6. TIME-GCM MLT Processes MOZART-3 WACCM-3 Chemistry CAM3 + extensions Dynamics + Physical processes NCAR Whole Atmosphere Community Climate Model • Based on The Community Atmosphere Model (CAM3) • 0-140 km (66 levels; Dz =1.3 km in lower stratosphere to 3 km in thermosphere) • Finite-volume dynamics • 30 minute time step • MOZART-3 chemistry package (55 species) • Upper atmosphere extensions: • Lindzen GW parameterization • Molecular diffusion • NO cooling • non-LTE long-wave heating in the 15 µm band of CO2 and the 9.6 µm band of O3 CCSM June 2006

  7. WACCM3 additions • The following processes are now dealt with in a self-consistent manner in WACCM: • Solar variability • Chemical heating • Airglow • Ion chemistry (5 ion species & electrons) • EUV and X-ray ionization • Auroral processes • Particle precipitation • Ion drag • Joule heating • Chemistry is completely interactive with dynamics CCSM June 2006

  8. Current interdivisional collaborators • Current external collaborations • Mark Baldwin (NWRA) • – annular modes • Natalia Calvo (U. of Madrid) and Marco Giorgetta (MPI, Hamburg) • – effects of ENSO on the middle atmosphere; comparison of models and reanalysis data • Charlie Jackman (NASA/Goddard) • – impacts of solar proton events on ozone • Judith Perlwitz and Martin Hoerling (NOAA/Boulder) • – climate impacts of changing chemistry and SST • Cora Randall et al. (CU/LASP) [plus John Gille (ACD/HIRDLS) and Laura Pan (ACD/UTLS initiative)] • – process-oriented evaluation of chemistry-climate models vs. observations CCSM June 2006

  9. WACCM • SABER: broadband IR radiometer onboard TIMED satellite; measures T, O3, H2O, CO2 Zonal-Mean T: JULY 140 K 270 K 200 K CCSM June 2006

  10. WACCM • URAP/UKMO: UARS/UK Met Office reference atmosphere, based upon UARS satellite observations assimilated with the UK Met Office GCM Zonal-Mean U: JULY CCSM June 2006

  11. WACCM SABER 11 ppm • SABER: broadband IR radiometer onboard TIMED satellite; measures T, O3, H2O, CO2 Zonal-Mean O3 : JULY CCSM June 2006

  12. 2. Research with WACCM CCSM June 2006

  13. Solar min/max simulations • Fixed solar minimum and solar maximum conditions (constant F10.7 and Kp typical of minimum/maximum) CCSM June 2006

  14. 15 years ea. solar maximum and minimum conditions • Smax: F10.7 = 210, Kp = 4 • Smin: F10.7 = 77, Kp = 2.7 definition of solar variability • Photolysis and heating rates are parameterized in terms of f10.7 and Kp CCSM June 2006

  15. WACCM (annual mean) Courtesy of Bill Randel (2005) Stratospheric temperature response SSU/MSU4 (1979-2003) CCSM June 2006

  16. WACCM (annual mean) SAGE I/II ozone change 3.6% 2.4% % ozone change over solar cycle % ozone change for 1% change in Mg II (~6% Mg II change over solar cycle) CCSM June 2006

  17. WACCM 1950-2003 WACCM 1979-2003 Ozone column vs. f10.7 regressions: WACCM and observations CCSM June 2006

  18. 1950-2003 trends simulation • An ensemble of “retrospective” runs, 1950-2003, including solar variability, observed SST, observed trends in GHG and halogen species, and observed aerosol surface area densities (for heterogeneous chemistry) CCSM June 2006

  19. SAGE-I 1979-1981 and SAGE-II 1984-2000 • Red inset on left covers approximately same region as observations on right • Agreement is quite good, including region of apparent “self-healing” in lower tropical stratosphere Calculated and Observed Ozone Trends CCSM June 2006

  20. Total Column Ozone Trends (Global) CCSM June 2006

  21. SSU + MSU 1979-1998 • Red inset on left covers approximately same region as observations on right • Note comparable modeled vs. observed trend in upper stratosphere, although model trend is somewhat smaller Calculated and Observed Temperature Trends CCSM June 2006

  22. Courtesy of Bill Randel (NCAR) Temperature Trends (Global), K / Decade CCSM June 2006

  23. CO2 decrease Note lack of trend at 80-90 km Ozone decrease and CO2 increase Antarctic O3 hole Whole-atmosphere zonal-mean T trend 1950-2003 CO2 increase (greenhouse effect) CCSM June 2006

  24. 21st century prognostic simulations • An ensemble of prognostic runs, 1975-2050, to look at climate change and ozone recovery in the 21st century. Follows WMO A1B scenario. • An additional ensemble assumed constant CO2, CH4, N2O to assess the role of stratospheric cooling by these gases. CCSM June 2006

  25. Global-mean ozone column recovery to 1980 values ~2040 1950-2003 sim 1980-2050 sim (A1B scenario) smoothed with 12-month running mean column minimum ~2000-2010 • 21st century prognostic simulation (red) shown together with the results of the 1950–2003 simulation (black) discussed earlier CCSM June 2006

  26. A1B scenario “no-climate change” scenario all smoothed with 12-month running mean Global-mean ozone column • A1B scenario produces “super-recovery” compared to “no climate change” simulation wherein CO2, N2O, CH4 are held at 1995 values. • This is due to colder stratospheric T in A1B scenario. CCSM June 2006

  27. 1950-2003 1980-2050 A1B 1980-2050 fix GHG Stratospheric “age of air” is also affected by changing GHG CCSM June 2006

  28. Upper atmosphere dynamics: The 2-day wave • Apart from the tides, the 2-day wave dominates high-frequency variability in the MLT • Has large amplitude at solstice, especially in the summer hemisphere • Has been interpreted as a normal mode (e.g., Salby, 1981), a result of baroclinic instability (e.g., Plumb, 1983), and a combination of both (e.g., Randel, 1994) • Comparison of WACCM simulations and observations by the SABER instrument on the TIMED satellite CCSM June 2006

  29. SABER T Spectrum Note concentration of variance along line of constant c in both data and model Similar spectral behavior in WACCM calculations as in SABER data Wavenumber/frequency T spectra at 36°N and 80 km (July) WACCM T Spectrum CCSM June 2006

  30. k=3, ~2-day SABER k=4, ~1.8 day SABER WACMM WACMM Components of 2-day wave in SABER data and WACCM simulation SABER observations and WACCM results for July CCSM June 2006

  31. k=2, ~3 day SABER k=2, ~ 2 day SABER WACCM WACCM … more components of 2-day wave in SABER data and WACCM CCSM June 2006

  32. 3. Future Work • Climate sensitivity to doubling CO2: CAM vs. WACCM • Impact of ozone hole and changing tropical SST on Arctic/Antarctic surface climate • Climatology of stratospheric sudden warmings: impacts of resolution, gravity wave parameterization, SST variability; relationship to annular modes • Process-oriented evaluation of model chemistry (comparisons with EOS/Aura observations) • Impact of solar proton events on mesospheric and stratospheric composition • Energy budget and dynamics of the MLT – comparison with SABER observations CCSM June 2006

  33. To keep in touch …. WACCM website and new model release • WACCM website is being hosted under ACD (http://waccm.acd.ucar.edu/index.shtml) • Website has been updated and reformatted • 2006 CSL proposal posted on site • WACCM3 description to be completed • Release WACCM3 in summer 2006 CCSM June 2006

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