The Impacts of the Indian Ocean warming trend on African Climate. - PowerPoint PPT Presentation

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The Impacts of the Indian Ocean warming trend on African Climate.

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The Impacts of the Indian Ocean warming trend on African Climate. Dan Hodson and Rowan Sutton NCAS Centre for Global Atmospheric Modelling Department of Meteorology – PowerPoint PPT presentation

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Title: The Impacts of the Indian Ocean warming trend on African Climate.


1
The 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
2
Outline
  • 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

3
Observations
4
1950-1999 Trend in Rainfall
Hoerling et al. J. Climate 2006
5
Experiments I
6
AGCM forced with Observed SSTs
7
FMA
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
8
JAS
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
9
AGCM forced with 1C Indian Ocean
10
(No Transcript)
11
AGCM Forced with 1?C Indian Ocean Anomaly
12
AGCM Forced with 1?C Indian Ocean Anomaly
13
Indian Ocean Temperature Trend
14
Indian Ocean SST Trend
C
15
Indian Ocean SST trend
0.02
-0.02
Annual mean SST trend 1951-1990 C/year
16
Atmosphere model force with Observed Indian Ocean
warming Trend
17
SST Anomalies
Sept
May
Jan
18
Indian Ocean SST Trend
C
19
Experiment
  • Five AGCMs
  • Arpege
  • CAM3
  • Echam5
  • GAM (IAP)
  • HadAM3
  • Indian Ocean Positive (IOP)
  • Indian Ocean Negative (ION)

20
Results
21
FMA
22
JAS
23
Caveats?
24
Observed MSLP trends
Copsey et al GRL 2006
25
MSLP Trends
26
Conclusions
  • 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?

27
(No Transcript)
28
Vertical Structure JAS
29
Vertical Structure FMA
30
Station rainfall trends 1950-1999 (JAS/FMA)
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