International C20C Project: Background for this Meeting

1. International C20C Project: Background for this Meeting J. Kinter, COLA, USA C. Folland, Met Office, UK Joint C20C/WGSIP Workshop 4-6 July 2005 Prague, Czech Republic

2. Background • Purpose: Characterize variability and predictability of climatic conditions and events of the past ~150 years associated with various slowly varying forcing functions including SST. • Initially focused on AGCMs forced with HadISST sea surface temperature and sea ice analysis

3. Background (continued) • Period of interest: 1871-current • Organization: • Jointly organized by Hadley Centre, UK & Center for Ocean-Land-Atmosphere Studies (COLA), USA • 15 different modeling groups participating internationally • CLIVAR project & reporting to WMO/CAS/WGNE • Now includes many other forcing data sets, including greenhouse gases, ozone, volcanic aerosols and solar variability • Being expanded to include use of coupled models in order to more accurately simulate modes of variability that are inherently coupled

4. Current Participating Groups • Bureau of Meteorology, Australia (www.bom.gov.au) • China Meteorological Agency, China (www.cma.gov.cn) • Center for Ocean-Land-Atmosphere Studies, USA (www.iges.org) • Centro de Previsão de Tempo e Estudos Climáticos, Brazil (www.cptec.inpe.br) • Department of Natural Resources, Mines & Energy, Queensland, Australia (www.nrm.qld.gov.au) • NASA Goddard Space Flight Center, USA (gmao.gsfc.nasa.gov) • Hadley Centre, Met Office, UK (www.metoffice.com/research/hadleycentre) • International Centre for Theoretical Physics, Italy (www.ictp.trieste.it) • MeteoFrance, France (www.meteo.fr) • Main Geophysical Observatory, Russia (www.mgo.rssi.ru) • Meteorological Research Institute, Japan (www.mri-jma.go.jp) • National Institute for Environmental Studies, Japan (www.nies.go.jp) • National Institute of Water and Atmospheric Research, New Zealand (www.niwa.cri.nz) • Seoul National University, Korea (www.snu.ac.kr:) • University of California at Los Angeles, USA (www.ucla.edu)

5. Special Topics • Predictability of seasonal to decadal phenomena • 1930s drought in USA (“Dust Bowl”) • 1962-63 European winter • Interannual to decadal variations in summer North European droughts • 2003 European heat wave • Decadal modulation of response to ENSO in Australia, Indian monsoon • Time series and trends • SOI, NAO, PNA, Asian monsoon rainfall, Sahel rainfall, Nordeste Brazil rainfall, MJO trends • Global and regional land surface air temperature trends • Others, e.g., river runoff trends

6. Links to CLIVAR • C20C became a CLIVAR activity in 2003 • Reports to Working Group on Numerical Experimentation (WCRP/CAS/WGNE) • One purpose of this meeting: Exploring link to WCRP Working Group on Seasonal to Interannual Prediction (WCRP/CLIVAR/WGSIP) • Also exploring link to WCRP Working Group on Coupled Modeling (WCRP/CAS/WGCM)

7. C20C Phases of Activity • Phase 1 (prior to 2003) : SST and sea ice • Hadley Centre provides HadISST1.1 SST and sea ice data set as lower boundary conditions • Integrate over 1871-2002 (at least 1949-2002) • Ensembles of at least 4 members • Phase 2 (2003 - ) : atmospheric composition • Greenhouse gases – CO2, O3, etc. • Aerosols (volcanic) • Solar variability • Phase 3 (2005 - ) : land surface variability • specified evolution of soil wetness and vegetation

8. Current Activities • Results of Third C20C Workshop were reported to CLIVAR 2004 Conference in June 2004 • Discussion with CLIVAR Working Group on Seasonal to Interannual Prediction, Oct 2004, Exeter. • Inputs to relevant sections of 2007 IPCC Fourth Assessment. • Planning for comparison to coupled models • Coupling to mixed layer or dynamical ocean in “Pacemaker” mode • Use of alternative SST data sets to HadISST in Pacemaker experiments including proposed HadISST2 and Reynolds SST data. • Coordination with WGSIP/WGCM • Efficient estimation of anthropogenic signals • Planning for changing land cover forcing experiments including the role of soil moisture feedback

9. Poster presented at the International CLIVAR 2004 Conference

10. Global 2m land surface air temperature Winter North Atlantic Oscillation Sahel rainfall Southern Oscillation Data contributed by: S.Grainger BMRC L. Marx COLA K.Jin CESRC/SNU A.Scaife Hadley Centre F.Kucharski ICTP P.Sporyshev MGO S.Kusunoki MRI J.Syktus QNRME Data analysis prepared by: A.Scaife, Hadley Centre

11. Issues • What are the limitations of AGCM runs that have no direct coupling to the ocean surface? Are local/regional fluxes misleading? • How should we include coupled models in C20C work, e.g. thermohaline-forced variations in climate? understanding interannual predictability? • How should we design the land cover experiment to most effectively meet C20C and land surface community goals?

12. Future … • Fourth C20C Workshop in autumn 2006 tentatively being planned for Exeter, UK. This may set the main change of direction of participants to Pacemaker Experiments and better define forcing data sets with participation of CLIVAR WG on Coupled Modeling. • Possible session at the winter 2006-7 Annual Meeting of the American Meteorological Society. • Extend C20C back to 1850 where possible. • Publication of papers on our key topics explicitly advertising C20C. This has already started, but needs to be more systematic. • Fifth C20C Workshop, tentatively set for late 2008 in Australia. • C20C can provide major input to Fifth IPCC Assessment Report 2010-12 with careful planning. This will be addressed at the Fifth Workshop.

13. This Meeting MONDAY • Workshop introduction • Coupled and uncoupled A-O models (3 sessions) TUESDAY • Uncoupled AGCM (2 sessions) • Discussion of coupled modeling for C20C WEDNESDAY • Sensitivity to land surface (1 session) • Discussion of land cover experimental design