Recorded presentation5.1
Arctic Rapid Change Pattern (ARP): An Accelerating Impetus for Recent Rapid Arctic Climate System Changes
Xiangdong Zhang, University of Alaska, Fairbanks, AK
Arctic climate system change has accelerated tremendously since the beginning of this century, and a strikingly extreme sea ice coverage loss occurred in summer 2007. However, the greenhouse gas concentration has continually increased gradually and the previously-identified driving role in Arctic climate change of the global- warming-forced positively-polarized trend of the Arctic/North Atlantic Oscillation (AO/NAO) has been substantially weakened. We report on drastic, systematic spatial changes in atmospheric circulations, showing a sudden jump from the conventional tri-polar AO/NAO to an unprecedented dipolar leading pattern, following accelerated northeastward shifts of the AO/NAO centers of action. This radically shifted spatial pattern – Arctic Rapid change Pattern (ARP) – represents the rapid climate change signature in atmospheric circulations, suggesting that global warming effect may have been erode the conventionally robust atmospheric circulation variability spatial structures, instead of only impacting its amplitude time evolution. Our analysis indicates that the atmospheric circulation pattern shift and ARP provides an accelerating impetus for the recent rapid Arctic climate system changes. These findings perhaps shed light on recent arguments about a tipping point of global-warming-forced climate change in the Arctic. In addition, the pattern shift has also been found to provide skillful predicative information for the observed extreme rapid change event.
Session 5, Rapid Polar Environmental Change
Tuesday, 19 May 2009, 8:30 AM-9:30 AM, Capitol Ballroom AB
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