CT1/CT3 Meeting 22-23 April 2013 Hamburg
Predictability associated with the Atlantic ocean SST variability
G. Gastineau, J. Garcia-Serrano, C. Frankignoul
Introduction
• Atlantic ocean SST variability : AMO + North Atlantic Horseshoe
• Are both pattern related? What are their influence on the European/American climate?
Data and methods
Data : • Atmosphere : 20CR-NOAA reanalysis (56 members)• SST : HadISST
Global warming influence removed :• SST : Regression over the global mean SST time series
removed • Atmosphere : detrend
Global SST warming
Atlantic Multidecadal Oscillation
AMO = low pass (10-yr) filtered North Atlantic SST
AMO-proj = SST filtered with a ¼ ½ ¼ filtered projected onto AMO spatial pattern
Climatic impact of AMO
Maximum covariance analysis
North Atlantic Horseshoe
Such mode is found in all ensemble members (at least for OND)
for N
AH si
gnifi
canc
e in
ON
D
SCR
Climate impact of NAH
Links horseshoe - AMO
AMO-projAMO-std
Non-stationarityMoving correlation between NAH and AMO using 20-yr window :
Moving correlation between NAH and NAO in NDJ using 20-yr window :
Ongoing work
• Remove remote influence of Indo-Pacific variability
• Explain the non-stationary in the AMO-NAH links
• Compare the relative influence of SST to that of snow cover and sea ice cover.
• Focus also on the summer impacts of AMO
The research leading to these results has received funding from the European Union 7th Framework Programme (FP7 2007-2013), under grant agreement n.308299NACLIM www.naclim.eu