Upload
alaina
View
32
Download
1
Tags:
Embed Size (px)
DESCRIPTION
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 University of Reading. Outline. Observations. Experiments I Atmosphere model forced with: - PowerPoint PPT Presentation
Citation preview
The Impacts of the Indian Ocean warming trend on
African Climate.
Dan Hodson and Rowan Sutton
NCAS Centre for Global Atmospheric ModellingDepartment of Meteorology
University of Reading
OutlineObservations.Experiments I
– Atmosphere model forced with:• Historical Observed Sea Surface Temperatures.• 1°C Anomaly in the Indian Ocean
Indian Ocean Temperature TrendExperiments II
– Atmosphere model force with Observed Indian Ocean warming Trend
ResultsConclusions and Caveats
Observations
Hoerling et al. J. Climate 2006
1950-1999 Trend in Rainfall
Experiments I
AGCM forced with Observed SSTs
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
FMA
AGCM Forced with Obs SSTs 1950-1999
Hoerling et al. J. Climate 2006
JAS
AGCM forced with 1°C Indian Ocean
+1°C
AGCM Forced with 1C Indian Ocean Anomaly
AGCM Forced with 1C Indian Ocean Anomaly
Indian Ocean Temperature Trend
Indian Ocean SST Trend
C
Indian Ocean SST trend
Annual mean SST trend 1951-1990 C/year
0.02
-0.02
Atmosphere model force with Observed Indian Ocean
warming Trend
Jan
May
Sept
SST Anomalies
Indian Ocean SST Trend
CIOP
ION
Experiment Five AGCMs
– Arpege – CAM3– Echam5– GAM (IAP)– HadAM3
Indian Ocean Positive (IOP) Indian Ocean Negative (ION)
Results
FMAVertical velocity Rainfall Surface Temperature
ARP
CAM
ECH
GAM
HAD
JASVertical velocity Rainfall Surface Temperature
ARP
CAM
ECH
GAM
HAD
Caveats?
Observed MSLP trends
Copsey et al GRL 2006
MSLP Trends
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?
Vertical Structure JAS
Vertical Structure FMA
Station rainfall trends 1950-1999(JAS/FMA)