1. Temperature trends in the upper troposphere/ lower stratosphere as revealed by CCMs and AOGCMs Eugene Cordero, Sium Tesfai Department of Meteorology San Jose State University, USA Veronika Eyring DLR Institute for Physics of the Atmosphere, Germany Neal Butchart Climate Research Division, Met Office, UK Outline Goals and Motivation 20th century 21st century

2. Aim: To determine if systematic differences exist between AOGCMs and CCMs simulations during the 20 th and 21 st centuries. Questions: 1.Are CCM’s better able to simulate the 20 th century atmosphere compared to AOGCM models? 2.What effect does ozone forcing have on temperature trends in the stratosphere and troposphere? 3.How will the SRES emission scenarios affect O 3 recovery?

3. AOGCM Simulations (IPCC 2007)  Coupled Atmosphere – Ocean General Circulation Models (AOGCMs) - IPCC AR4 (CMIP3)  Simulations from 17 international research groups (23 model simulations)  Variety of emission scenarios –20th century –21st century - various scenarios  Model focus is on surface and troposphere Cordero and Forster, 2006: Stratospheric variability and trends in models used for the IPCC AR4, ACP.

4. CCM Simulations (WMO/UNEP 2006)  Coupled Chemistry Climate Models (CCM)  Simulations from 13 international research groups  Two primary sets of simulations –20th century (REF1) –21st century (REF2)  Model focus is primarily on evolution of the ozone layer. Eyring et al., 2006: Assessment of temperature, trace species, and ozone in chemistry climate model simulations of the recent past, JGR. Eyring et al., 2007: Multimodel projections of stratospheric ozone in the 21st century, JGR

5. Coupled Chemistry-Climate Models (CCMs)

6. AOGCM Model Forcings Cordero and Forster, 2006

7. ModelGroup and locationHoriz. resolution Vertical Layers / Upper Boundary AMTRACGFDL, USA2° x 2.5°48 L / 0.0017 hPa CCSRNIESNIES, Tokyo, Japan2.8° x 2.8°34 L / 0.01 hPa CMAMUniv Toronto/York Univ/Environment Canada 3.75 ° x 3.75° 71L / 0.0006 hPa E39CDLR Oberpfaffenhofen, Germany3.75 ° x 3.75° 39L / 10 hPa GEOS CCMNASA/GSFC, USA2° x 2.5°55 L / 0.01hPa LMDZreproIPSL, France2.5° x 3.75°50 L / 0.07 hPa MAECHAM4CHE M MPI Mainz, MPI Hamburg, Germany3.75 ° x 3.75° 39 L / 0.01 hPa MRIMRI, Tsukuba, Japan2.8° x 2.8°68 L / 0.01 hPa SOCOLPMOD/WRC and ETHZ, Switzerland3.75 ° x 3.75° 39 L / 0.1 hPa ULAQUniversity of L'Aquila, Italy10° x 22.5°26 L / 0.04 hPa UMETRACUK Met Office, UK; NIWA Lauder, NZ2.5° x 3.75°64 L / 0.01 hPa UMSLIMCATUniversity of Leeds, UK2.5° x 3.75°64 L / 0.01 hPa WACCMNCAR, USA4° x 5°66 L / 10 -6 hPa CCM Participating Models

8. Tropopause Stratopause AOGCM Vertical Model Levels Cordero and Forster, 2006 CCM Models

9. AOGCM Temperature bias: Models with high lid compared to models with low lid High lid models (> 45km) Low lid models (< 45km) NCEP  2σ Cordero and Forster, 2006

10. 20 th Century Temperature Time Series and Trends

11. Annual Global Temperature Anomaly @ 50 hPa

12. Pressure (hPa) Global Temperature Trends (1958-99) º K/decade

13. AOGCM/CCM Global Temperature Trends (1958-99) Yes O 3 No O 3 Sonde *

14. AOGCM/CCM Global Temperature Trends (1980-99)

15. SH Extratropics AOGCM/CCM Global TempTrends (1980-99)

16. 21 st Century Simulations AOGCMs A1/B2 CCMs A1B Trends in temperature

17. Global Temperature @ 10hPa A2/A1B Scenario

18. Global Temperature @ 50hPa A2/A1B Scenario

19. Global Temp Trends (2000-2050) A2/A1B Scenario

20. SON - SH extratropics- Temp Trends A2/A1B Scenario

21. Global Average Temperature Trend 2000-2100 Pressure (hPa) º K/decade 2000-2050 Temp Trends A2/B1 Scenario

22. Global Average Temperature Trend 2000-2100 Pressure (hPa) º K/decade 2000-2050 Temp Trends A2/A1B/B1 Scenario

24. Global Average Temperature Trend 2000-2100 Pressure (hPa) º K/decade 2000-2100 Temp Trends A2/A1B/B1 Scenario

25. Summary  20 th Century –The AOGCM and CCMs produce similar temperature trends (for models including ozone forcing). –Models trends without ozone forcing appear different in upper troposphere for some regions.  21 st Century –Stratospheric temperature strongly affected by emission scenario. –CCM simulations of ozone recovery may not based on a middle range emission scenario.

26. Steps Forward  Determine ozone forcing fields in AOGCM simulations (future scenarios).  CCM and AOGCM model simulations where interactive chemistry can be isolated.  Further investigate seasonal trends at different latitude ranges.

28.  Aim of the Study: –PART 1: Evaluation of the current generation of coupled chemistry- climate models (CCMs) –PART 2: Long-term decadal projections of stratospheric ozone in the 21 st century  Motivation: –WMO/UNEP Assessment 2007, in particular Chapter 6: The Ozone Layer in the 21st Century (Greg E. Bodeker, Darryn W. Waugh et al.) –IPCC 2007, in particular Chapter 7: Couplings Between Changes in the Climate System and Biogeochemistry (Ken L. Denman, Guy Brasseur, et al.) The goal of CCMVal is to improve understanding of CCMs through process- oriented evaluation, along with discussion and coordinated analysis of science results.

29. Annual Global Temperature @ 50 hPa

30. AOGCM Annual Global Temperature @ 50 hPa

31. Pressure (hPa) Global Average Temperature Trend 2000-2050

32. Pressure (hPa) Global Average Temperature Trend 2000-2050 (Fixed ozone)

33. Global Temperature Trends (1980-99)

34. Tropical Temperature Trends (1979-99)AOGCM/CCM Global Temperature Trends (1958-99)