1. 4 th WOAP Meeting 29 March 2010 K. E. Taylor The Working Group on Coupled Modeling Karl E. Taylor Program for Climate Model Diagnosis and Intercomparison (PCMDI) with credit and thanks to Sandrine Bony Presented to the Fourth WCRP Observation and Assimilation Panel Meeting Hamburg, Germany 29 March 2010

2. PCMDI 4 th WOAP Meeting 29 March 2010 Who are the WGCM? Members Sandrine Bony (co-chair) Gerald Meehl (co-chair) Veronica Eyring Marco Giorgetta David Karoly M. Kimoto Corinne Le Quéré Natalie Mahowald Catherine Senior Bin Wang Ex-Officio Members Gokhan Danabasoglu Helge Drange Greg Flato Filippo Giorgi John Mitchell Ronald Stouffer Karl Taylor

3. PCMDI 4 th WOAP Meeting 29 March 2010 What is the WGCM’s mission? Foster the development of coupled climate models (and now ESMs) Coordinate model experiments and inter-comparisons to: à better understand natural climate variability à predict the climate response to natural & anthropogenic perturbations Promote and facilitate model evaluation and diagnosis of shortcomings A balance among: Predicting – Evaluating - Understanding

4. PCMDI 4 th WOAP Meeting 29 March 2010 Major challenges How can we improve our confidence in climate models? How can we assess the credibility of model projections ?

5. 4 th WOAP Meeting 29 March 2010 K. E. Taylor LES models Cloud Resolving Models Single Column Models 3D-Climate Models NWP Models High resolution global models (global CRM, MMF) Global observational datasets Field campaigns & instrumented sites How can we gauge and gain confidence in GCMs projections? (1) Bottom-Up approach : evaluate and improve the physical basis of climate models through large-scale and process-scale evaluations Analysis & Understanding climate change Model projections

6. 4 th WOAP Meeting 29 March 2010 K. E. Taylor LES models Cloud Resolving Models Single Column Models 3D-Climate Models NWP Models High resolution global models (global CRM, MMF) Global observational datasets Field campaigns & instrumented sites How can we gauge and gain confidence in GCMs projections? (1) Bottom-Up approach : evaluate and improve the physical basis of climate models through large-scale and process-scale evaluations (2) Top-Down approach : understand the models' results & identify critical processes to provide guidance for specific observational tests/process studies and model improvements Analysis & Understanding climate change Model projections

7. PCMDI 4 th WOAP Meeting 29 March 2010 The second approach has traditionally dominated WGCM’s interests, but this is changing. Current activities focus on understanding why model projections differ à e.g., quantifying the strength of individual feedbacks across models. Evaluate climate models over a wide range of scales and phenomena à From weather to paleo à From global to regional à From individual physical processes to climate (across all physical and biogeochemical components) Explore how model formulation and present-day model performance translate to reliability of climate projections  Perhaps the biggest challenge of all.

8. PCMDI 4 th WOAP Meeting 29 March 2010 CMIP3 transformed climate science by enabling community- wide participation in the analysis of model output. 35 Tbytes of model output stored at PCMDI More than 765 TB downloaded More than 3,000 users More than 550 publications Aug 2009Jan 2007 (AR4 WGI) Nov 2004 Courtesy of Bob Drach (PCMDI)

9. PCMDI 4 th WOAP Meeting 29 March 2010 What are prospect for CMIP5? Better understand robust and uncertain aspects of climate change à Enable quantification of strengths of major feedbacks Include carbon cycle component (ESM’s) Better meet the needs of the “impacts” community à A more comprehensive set of model output Provide information needed to assess adaptation and mitigation strategies Coordinate/integrate across the modeling community: à CMIP includes portions of: C4MIP, PMIP, AMIP, CFMIP, Aqua-planet

10. 4 th WOAP Meeting 29 March 2010 K. E. Taylor CMIP5: Three Suites of Experiments “Long-Term” (century & longer) TIER 1 TIER 2 CORE evaluation & projection diagnosis “Near-Term” (decadal prediction) (initialized ocean state) hindcasts & forecasts CORE TIER 1 TIER 2 TIER 1 AMIP “time-slice” CORE Atmosphere-Only (for computationally demanding and NWP models) TIER 1 TIER 2 Taylor et al. 2008, http://cmip-pcmdi.llnl.gov/cmip5

11. 4 th WOAP Meeting 29 March 2010 K. E. Taylor Example: CMIP5 long-term suite of experiments An important focus is model evaluation and understanding... D & A ensembles Control, AMIP, & 20 C RCP4.5, RCP8.5 natural-only, GHG-only individual forcing RCP2.X, RCP6 extend RCP4.5 to 2300 extend RCP8.5 & RCP2.X to 2300 ensemble of abrupt 4xCO 2 5-yr runs aqua planet (clouds) uniform ΔSST (clouds) Mid-Holocene & LGM last millennium E-driven RCP8.5 E-driven control & 20 C patterned ΔSST (clouds) aerosol forcing ca. 2000 AC&C4 (chemistry) 1%/yr CO 2 (140 yrs) abrupt 4XCO 2 (150 yrs) fixed SST with 1x & 4xCO 2 radiation code sees 1xCO 2 (1%/yr or 20C+RCP4.5) carbon cycle sees 1XCO 2 (1%/yr or 20C+RCP4.5) Understanding Model Evaluation Climate Projections Green subset is for coupled carbon-cycle climate models only ensembles: AMIP & 20 C

12. 4 th WOAP Meeting 29 March 2010 K. E. Taylor CMIP now involves many WCRP/IGBP partners Example: CMIP5 long-term suite of experiments Detection-Attribution (IDAG) Paleo (PMIP, IGBP- PAGES) Cloud and moist processes (CFMIP-GCSS WGNE) Carbon-climate feedbacks (C4MIP, IGBP-AIMES) Integrated Assessment Consortium (IAM), connection to WG-III + Satellite simulators & process diagnostics (CFMIP-GCSS) Chemistry, aerosols (SPARC, AC&C, CCMVal, aerocom)

13. PCMDI 4 th WOAP Meeting 29 March 2010 WGCM (with others) promotes a variety of community- wide activities to advance climate modeling Mentioned already: à SPARC & IGBP/IGAC (CCMVal, AeroCom..): chemistry & aerosols à WGCM & IGBP/PAGES (PMIP): paleoclimate à WGCM, GCSS, and WGNE (CFMIP): clouds and cloud feedbacks à WGCM, IGBP/AIMES (C4MIP): carbon cycle à IDAG: detection and attribution studies WGNE/WGCM (Transpose-AMIP): evaluation of climate models in NWP mode CLIVAR WGSIP, WGOMD : seasonal to interannual prediction, ocean TFRCD (CORDEX) : regional GEWEX GCSS (GPCI) : processes WGNE/WGCM Metrics panel CF metadata conventions for archiving and sharing climate data WGCM endorsed demonstration study (GeoMIP): geo-engineering

14. PCMDI 4 th WOAP Meeting 29 March 2010 WGCM’s Challenge to WOAP Push to make observations as easily available and useable as climate model output generated by CMIP. à Provide easy access and guidance on quality and limitations à Following CMIP3, store observational data in a standard way and make it available through a common portal. The WGCM has endorsed a NASA/JPL pilot initiative to provide satellite data in a form useful to CMIP5 (Joao Texeira, Duane Waliser, Jerry Potter, S Boland). A similar NOAA initiative may be launched soon, and this in the work plans ISENES (a European project to provide infrastructure support for climate model research) These new projects were all partially inspired by CMIP The WGCM would like to see similar efforts undertaken by other providers of satellite and in-situ observations.

15. PCMDI 4 th WOAP Meeting 29 March 2010 WGCM’s Challenge to WOAP Provide encouragement and possibly a framework whereby à the observational and climate modeling community would interact to identify observational data sets useful in model evaluation à The highest priority would be to consider the CMIP output -– variables, temporal/spatial sampling, time-periods. Establish guidelines for à Metadata that will facilitate search and discovery. à Formats and metadata that will facilitate analysis (as provided by the CF metadata standard) Develop a strategy for making multiple datasets developed for this purpose accessible in a way that parallels the CMIP model output archive.

16. PCMDI 4 th WOAP Meeting 29 March 2010

17. PCMDI 4 th WOAP Meeting 29 March 2010 List of CMIP5 output fields http://cmip-pcmdi.llnl.gov/cmip5/output_req.html Domains: à Atmosphere (including aerosols) à Ocean (including carbon cycle variables) à Land surface (including carbon cycle variables) à Cryosphere Temporal sampling à Annual à Monthly à Daily (including max., min. & mean surf. Air T, precip. humidity, surf. wind, PSL; many more 2-d & 3-d fields for 1950-2005) à 6-hourly à 3-hourly (including from 1950-2005) à ~ half-hour (but not globally)

18. PCMDI 4 th WOAP Meeting 29 March 2010 Model output characteristics Specified template for filenames and directory structure Additional metadata à modeling_realm à tracking_id à model_id à creation_date à Forcing à initialization_method, à physics_version Output may be on native grid, rather than longitude- latitude cartesian

19. 4 th WOAP Meeting 29 March 2010 K. E. Taylor CMIP5 Decadal Prediction Experiments additional predictions Initialized in ‘01, ’02, ’03 … ’09 100-yr “control” & 1% CO 2 prediction with 2010 Pinatubo- like eruption alternative initialization strategies atmos. chemistry &/or aerosols &/or regional air quality AMIP increase ensemble sizes from O(3) to O(10) members hindcasts without volcanoes 30-year hindcast and prediction ensembles: initialized 1960, 1980 & 2005 10-year hindcast & prediction ensembles: initialized 1960, 1965, …, 2005

20. 4 th WOAP Meeting 29 March 2010 K. E. Taylor CMIP5 Atmosphere-Only Experiments (targeted for computationally demanding and NWP models) AMIP (1979-2008) AMIP ensemble AMIP SSTs with 4XCO 2 aqua planet (clouds) uniform ΔSST (clouds) patterned ΔSST (clouds) future “time-slice” (2026-2035) Future “time-slice” ensemble