Title: The Impacts of the Indian Ocean warming trend on African Climate.
1The Impacts of the Indian Ocean warming trend
onAfrican Climate.
Dan Hodson and Rowan Sutton
NCAS Centre for Global Atmospheric
Modelling Department of Meteorology University of
Reading
2Outline
- Observations.
- Experiments I
- Atmosphere model forced with
- Historical Observed Sea Surface Temperatures.
- 1C Anomaly in the Indian Ocean
- Indian Ocean Temperature Trend
- Experiments II
- Atmosphere model force with Observed Indian Ocean
warming Trend - Results
- Conclusions and Caveats
3Observations
41950-1999 Trend in Rainfall
Hoerling et al. J. Climate 2006
5Experiments I
6AGCM forced with Observed SSTs
7FMA
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
8JAS
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
9AGCM forced with 1C Indian Ocean
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11AGCM Forced with 1?C Indian Ocean Anomaly
12AGCM Forced with 1?C Indian Ocean Anomaly
13Indian Ocean Temperature Trend
14Indian Ocean SST Trend
C
15Indian Ocean SST trend
0.02
-0.02
Annual mean SST trend 1951-1990 C/year
16Atmosphere model force with Observed Indian Ocean
warming Trend
17SST Anomalies
Sept
May
Jan
18Indian Ocean SST Trend
C
19Experiment
- Five AGCMs
- Arpege
- CAM3
- Echam5
- GAM (IAP)
- HadAM3
- Indian Ocean Positive (IOP)
- Indian Ocean Negative (ION)
20Results
21FMA
22JAS
23Caveats?
24Observed MSLP trends
Copsey et al GRL 2006
25MSLP Trends
26Conclusions
- AGCMs forced with warm Indian Ocean capture some
of the trends in African rainfall (both FMA and
JAS). - Trends associated with changes in subsidence/
changes in Walker Circulation. - Can we use AGCMs to model past changes in this
way?
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28Vertical Structure JAS
29Vertical Structure FMA
30Station rainfall trends 1950-1999 (JAS/FMA)