1. Polar Climate Change and the Arctic Oscillation in CCSM3 IPCC Scenario Simulations
June
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

3. Sea Ice Extent
Sea Ice Concentration

4. review “Dynamics of recent climate change in the Arctic”
Moritz et al. (Science 2002)
review “Dynamics of recent
climate change in the Arctic”
Overland and Wang, 2005: The Arctic climate paradox: The
recent decrease of the Arctic Oscillation

6.
TAS EOF1
TAS EOF2
SLP EOF1

7. A2 A1B B1 PDF of the AO index (SLP EOF1) Red: 21st century
Black:20th century
A1B B1

8. Conclusions
The AO is the dominant mode in the wintertime atmosphere and sea ice variability in the 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.

11. Surface Temperature EOF1

12. Surface temperature EOF2

13. Sea level pressure EOF1

14. 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