1. Adam Scaife Hadley Centre, Met Office, Exeter, UK.
Using C20C to test models
Adam Scaife
Hadley Centre, Met Office, Exeter, UK.

2. Some Key Indices collected:
Land Surface Temperature (annual mean)
Darwin and Tahiti PMSL (monthly)
Iceland and Azores PMSL (DJF)
Sahel rainfall (JJAS)
Indian monsoon rainfall (Fred K.)
Contact
Model
Ensemble Means?
Ensemble members?
T.Zhou
GAMIL / CAM2 x
K.Jin /J.Kinter
NCEP CFS / COLA
P.Pegion
NASA GSFC
F.Kucharski
ICTP
S.Kusunoki
MRI-JMA
P.Sporyshev
MGO
A.Voldoire
METEO FR.
S.Grainger
BMRC
Jin
CESRC
J.Syktus
QNRME
J.Yoon
UMCP
© Crown copyright 2004

3. Normalised indices
© Crown copyright 2004

4. Absolute Anomalies
© Crown copyright 2004

5. Conceptual model for analysis
Potentially predictable,
“forced” and well
modelled
YES
20th Century Climate
Event
(e.g. surface T trend)
Consistent with
ensemble means?
Unpredictable internal
variation but well
modelled
YES NO
Consistent with
ensemble members?
Poorly modelled in this
experiment:
missing process/forcing NO
© Crown copyright 2004

6. Ensemble mean changes Land temperature 1970-2000 Sahel rainfall
NAO index
C20C model →
C20C model →
C20C model →
Within range of model
ensemble means so:
“Potentially predictable,
forced and well modelled”
Outside range of model
ensemble means:
small part is forced
Outside range of model
ensemble means:
not forced
© Crown copyright 2004

7. Ensemble member changes:
Sahel rainfall
NAO index
C20C model →
C20C model →
Outside range of ensemble
members:
Missing process or forcing
Outside range of ensemble
members:
Missing process or forcing
© Crown copyright 2004

8. Conclusions / Further work
For poorly modelled changes: AGCM vs PACEMAKER, aerosol vs no aerosol?
Other events and changes:
Dustbowl diagnostic?
Indian Monsoon changes?
Original C20C list…
Variability in SOI, NAO etc
Extremes?
2D data?
SST relationships?
Is this the basis for a C20C paper which examines whether we can explain major climate events of the past 100 years?
© Crown copyright 2004