The response of winter Arctic sea ice to Arctic Oscillation and dipole anomaly in the atmosphere
Jia Wang, University of Alaska, Fairbanks, AK; and B. Wu and J. E. Walsh
This paper investigates an atmospheric circulation anomaly-dipole structure anomaly in the arctic atmosphere, and its relationship with the winter sea ice motion, based on International Arctic Buoy Programme Data (1979-1998) and datasets from the National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) for the period of 1960-2002. The dipole structure anomaly is the second-leading mode of EOF of monthly mean SLP north of 70°N during the winter season (Oct.—Mar.), which accounts for 13% of the variance. One of its two anomaly centers is over the Canadian Archipelago; the other is situated over northern Eurasia and the Siberian marginal seas. Due to the dipole structure anomaly’s strong meridionality, it becomes an important mechanism to drive both anomalous sea ice export out of the Arctic Basin and cold air outbreaks into the Barents Sea, the Nordic Seas and northern Europe. When the dipole anomaly remains in its positive phase, that is, negative SLP anomalies appear in northern Eurasia and the Siberian marginal seas with the concurrent positive SLP over the northern American and Greenland, there are large-scale changes in the intensity and character of sea ice transport in the Arctic Basin: the weakening of the Beaufort Gyre, the increase in sea ice export out of the Arctic Basin through Fram Strait and the northern Barents Sea; enhanced sea ice import from the Laptev Sea and the East Siberian Sea into the Arctic Basin. Consequently, there is more than normal sea ice appearing in the Greenland and the Barents Seas during the positive phase of the dipole anomaly. The dipole anomaly shows a predominant 2-year periodicity, with a weak 5~7-year periodic variability. A coupled ice-ocean model (CIOM) was used to further examine responses of sea ice motion to both the Arctic Oscillation and dipole anomaly. The spatial patterns of sea ice and ocean are identified in response to Arctic Oscillation and dipole anomaly.
Joint Poster Session 2, Formal Poster Viewing - High Latitude Climate Variability and Change (Joint with the Eight Conference on Polar Meteorology and the 16th symposium on Global Change & Climate Variations)
Thursday, 13 January 2005, 9:45 AM-11:00 AM
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