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

CCSM June Outline 1.WACCM overview 2.Research with WACCM –Solar cycle impacts – trend simulations –21 st century prognostic simulations –Upper atmosphere dynamics (2-day wave) 3. Future work

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

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

CCSM June Overview of WACCM

CCSM June NCAR Whole Atmosphere Community Climate Model MOZART-3 CAM3 WACCM-3 TIME-GCM Chemistry Dynamics + Physical processes MLT Processes + extensions Based on The Community Atmosphere Model (CAM3) km (66 levels;  z =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 CO 2 and the 9.6 µm band of O 3

CCSM June 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 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 Zonal-Mean T: JULY WACCM 140 K 270 K 200 K SABER: broadband IR radiometer onboard TIMED satellite; measures T, O3, H 2 O, CO 2

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

CCSM June Zonal-Mean O 3 : JULY 11 ppm WACCM SABER SABER: broadband IR radiometer onboard TIMED satellite; measures T, O3, H 2 O, CO 2

CCSM June Research with WACCM

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

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

CCSM June SSU/MSU4 ( ) Courtesy of Bill Randel (2005) WACCM (annual mean) Stratospheric temperature response

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

CCSM June Ozone column vs. f10.7 regressions: WACCM and observations WACCM WACCM

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

CCSM June Calculated and Observed Ozone Trends SAGE-I and SAGE-II 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

CCSM June Total Column Ozone Trends (Global)

CCSM June Calculated and Observed Temperature Trends SSU + MSU 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

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

CCSM June Whole-atmosphere zonal-mean T trend Note lack of trend at km Ozone decrease and CO 2 increase CO 2 increase (greenhouse effect) Antarctic O 3 hole CO 2 decrease

CCSM June An ensemble of prognostic runs, , to look at climate change and ozone recovery in the 21 st century. Follows WMO A1B scenario. An additional ensemble assumed constant CO 2, CH 4, N 2 O to assess the role of stratospheric cooling by these gases. 21 st century prognostic simulations

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

CCSM June Global-mean ozone column all smoothed with 12-month running mean A1B scenario “no-climate change” scenario A1B scenario produces “super-recovery” compared to “no climate change” simulation wherein CO 2, N 2 O, CH 4 are held at 1995 values. This is due to colder stratospheric T in A1B scenario.

CCSM June Stratospheric “age of air” is also affected by changing GHG A1B fix GHG

CCSM June 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 Upper atmosphere dynamics: The 2-day wave

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

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

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

CCSM June Future Work Climate sensitivity to doubling CO 2 : 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 To keep in touch …. WACCM website and new model release WACCM website is being hosted under ACD ( Website has been updated and reformatted 2006 CSL proposal posted on site WACCM3 description to be completed Release WACCM3 in summer 2006