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Temperature trends in the upper troposphere/ lower stratosphere as revealed by CCMs and AOGCMs

Temperature trends in the upper troposphere/ lower stratosphere as revealed by CCMs and AOGCMs. Outline Goals and Motivation 20th century 21st century. Eugene Cordero, Sium Tesfai Department of Meteorology San Jose State University, USA Veronika Eyring

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Temperature trends in the upper troposphere/ lower stratosphere as revealed by CCMs and AOGCMs

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  1. Temperature trends in the upper troposphere/ lower stratosphere as revealed by CCMs and AOGCMs • Outline • Goals and Motivation 20th century 21st century 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

  2. Aim:To determine if systematic differences exist between AOGCMs and CCMs simulations during the 20th and 21st centuries. Questions: • Are CCM’s better able to simulate the 20th century atmosphere compared to AOGCM models? • What effect does ozone forcing have on temperature trends in the stratosphere and troposphere? • How will the SRES emission scenarios affect O3 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. CCM Participating Models

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

  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. 20th Century Temperature Time Series and Trends

  11. Annual Global Temperature Anomaly @ 50 hPa

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

  13. Yes O3 No O3 Sonde * AOGCM/CCM Global Temperature Trends (1958-99)

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

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

  16. 21st Century Simulations AOGCMs A1/B2CCMs 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. Pressure (hPa) 2000-2050 Temp Trends A2/B1 Scenario Global Average Temperature Trend 2000-2100 ºK/decade

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

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

  24. Summary • 20th 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. • 21st Century • Stratospheric temperature strongly affected by emission scenario. • CCM simulations of ozone recovery may not based on a middle range emission scenario.

  25. 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.

  26. The goal of CCMVal is to improve understanding of CCMs through process-oriented evaluation, along with discussion and coordinated analysis of science results. • 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 21st 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.)

  27. Annual Global Temperature @ 50 hPa

  28. AOGCM Annual Global Temperature @ 50 hPa

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

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

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