1. CLIVAR International Climate of the 20th Century (C20C) Project
Jim Kinter, COLA
Chris Folland, Hadley Centre,
Met Office
4th C20C Workshop, Exeter, UK
13 March 2007

2. C20C Project in the Future: Issues for Consideration
Experimental design
Sharing data and multi-model consensus
Linkage to WGSIP
Decadal prediction
Extension to 1850
Contributions to AR5
Publications
Highly encouraged!
Live list compiled:

3. Experimental Design Pacemaker Land Use and Change (LUC)
Are additional experimental protocols needed?
Other regions in which to specify time-varying SST
Standard formulation for Q-flux
Dynamical ocean models
Land Use and Change (LUC)
Soil moisture and land use changes sensitivity
LUC in AMIP-type vs. Pacemaker-type format
Experiments w/ and w/o time variation of GHG
WAMME-oriented experiments
Phenomena-Focused Experiments (subsets of C20C group)
West African Monsoon Modeling and Evaluation (WAMME)
Asian monsoon
Influence of the stratosphere on seasonal predictability

4. Sharing Data and Multi-Model Consensus
It is imperative that modeling groups make their data available to all other C20C participants
Modality? (license agreements, co-authorship …)
Technical matters (FTP? GDS? Central archive?)
Some work has already been done on model consensus (Scaife, Kucharski) -- what other systematic efforts should be undertaken?

5. Linkage to WGSIP
WMO/WCRP Working Group on Seasonal to Interannual Prediction (WGSIP) works in C20C-related areas
develop a program of numerical experimentation for S-I variability & predictability, paying special attention to assessing & improving predictions
develop appropriate data assimilation, model initialization & forecasting procedures for S-I predictions, considering such factors as observing system evaluation, use of ensemble & probabilistic methods and statistical and empirical enhancements
advise CLIVAR SSG on the status of S-I forecasting & adequacy of CLIVAR observing system, and liaise with JSC/CLIVAR WGCM and JSC/CAS WGNE
How can C20C work together with WGSIP more closely?
Issue: “no cheating”
WCRP Workshop on Seasonal Prediction
Barcelona, Spain, 4-7 June 2007
Should C20C and WGSIP extend to decadal prediction in a changing climate?

6. Seasonal to Decadal Prediction
Rigorously defined experiments needed
Investigate mechanisms - do they have a bearing on predictability?
Consistent with "classical" C20C goals:
Determine the extent to which atmospheric models are able to simulate the observed climate variations during the 20th century
Determine potential ability of ensembles of AGCM runs to simulate specific historical events such as regional floods and droughts, the Dust Bowl in North America, the persistent drought in the Sahel and other extremes
Attribute origin of observed climate trends over past century

7. Estimated PDO CGCM OBS Estimated NPO CGCM OBS
Long run of COLA Anomaly Coupled GCM
Point here is that models are capable of capturing much of this variability: Issues are then to understand the mechanisms, assess predictability and make predictions to the extent possible and understand how this variability is impacted by a changing climate.

8. NP Index Regression: Heat
Content And SST Along 42N
Heat Content And SST
Along 42N and 180
Lag-Lead (years)
North Pacific Index = SST Averaged from and 40-45N

9. North Pacific Index Idealized Prediction Experiments
“Observations”
“Observations”
Ensemble
Predictions
Ensemble
Predictions
Lead Time (months)
Lead Time (months)

10. Extension to 1850 Long-stated goal
How many groups have done this? Plan to do it?
What are the issues w.r.t. the forcing data sets?

11. Contributions to IPCC AR5
The Intergovernmental Panel on Climate Change (IPCC) has begun to release its 4th Assessment Report (AR4)
C20C is well-positioned to contribute in a major way to AR5, anticipated in
What specific experiments are needed to get ready for AR5?