Polar Climate Change and the Arctic Oscillation in CCSM3 IPCC Scenario Simulations
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Transcript of Polar Climate Change and the Arctic Oscillation in CCSM3 IPCC Scenario Simulations
Polar Climate Change and the Arctic Oscillation in CCSM3 IPCC
Scenario Simulations
June22 2006
Haiyan Teng
NCAR/CGD
H. Teng, W. M. Washington, G. A. Meehl, L.E. Buja and G. W. Strand, 2006: Twenty-first century Arctic climate change in the CCSM3 IPCC scenario simulations, Climate Dynamics
Sea Ice Extent Sea Ice Concentration
http://nsidc.org/data/seaice_index/
Overland and Wang, 2005: The Arctic climate paradox: Therecent decrease of the Arctic Oscillation
Moritz et al. (Science 2002) review “Dynamics of recentclimate change in the Arctic”
TAS EOF1
TAS EOF2
SLP EOF1
1870-2099
PDF of the AO index (SLP EOF1)
Red: 21st centuryBlack:20th centuryA2
A1B
B1
Conclusions
• The AO is the dominant mode in the wintertime atmosphere and sea ice variability in the 1870-1999 historical runs.
• The AO shifts to the positive phase in response to anthropogenic forcing in the 21st century but the simulated AO trends are smaller than the observed.
• The AO plays a secondary role (<10% of the total variance) in the 21st century while 50%-70% of the total variances are explained by the warming trend.
Surface Temperature EOF1
Surface temperature EOF2
Sea level pressure EOF1
Questions
• How does the AO respond to the anthropogenic forcing?
• Thinning of current Arctic sea ice: triggered by the early 1990s’ positive AO?
• Climate variability under a warming trend