1. National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory Princeton, NJ 08542 http://www.gfdl.noaa.gov Evolution of Stratospheric Temperature in Climate Model Simulations John Austin

2. Coupled chemistry-climate model simulations Uniform, observed forcings (solar, GHGs, aerosols, SSTs/sea ice). 12 different models: complete climate models with reasonably complete stratospheric chemistry. Some runs have simplified tropospheric chemistry Some runs include several ensembles Period covered 1960-2050 mostly. Eyring et al. JGR, submitted. CCMval: Description and runs

4. Climatology of the final warming (S)

5. Monthly mean 50 hPa T

6. 100 hPa seasonal variation

7. GFDL climate model, coupled chemistry 48L model, upper boundary ~ 0.002 hPa Horizontal resolution 2 x 2.5 deg. Finite Volume dynamical core Comprehensive stratospheric chemistry; simplified tropospheric chemistry 3 member ensemble (1) 1960-2005 with observed forcings (2) 1990-2100 with A1B etc. forcings and SSTs from GFDL IPCC runs. AMTRAC: Description and runs

8. Mean Ozone trend 1980-1999

9. Observed ozone trends 1980-1999 (Randel pers. comm., 2005) Observed ozone trend

13. Temperature solar cycle

14. Ozone solar cycle

17. AMTRAC polar spring lower stratosphere temperature evolution 1960-1999

18. AMTRAC polar lower stratospheric temperature evolution, 12-month running mean

19. AMTRAC (colored lines) and observed (black line) global average temperature for 1960 to 2005 weighted in the vertical by the MSU4 weighting function.

20. SOCOL MSU-4 equivalent temperature (25 months running mean) courtesy Schnadt et al.

21. Conclusions Past T trends are in reasonable agreement with observations for the period 1980-2000 in the lower and upper stratosphere. A solar cycle in T occurs in model results, but is smaller than the SSU solar cycle. In the global average, the lower stratosphere temperature evolution agrees well with observations. Tropopause T decreases 1960-2005 (0.16 K/decade) and increases thereafter (not shown) at 0.23 K/decade. Much work is yet to be done within CCMval and on individual models.