A vorticity based analysis of the Beaufort Anticyclone

The Beaufort Anticyclone is the dominant pressure feature over the Arctic Ocean and has a large influence on the surface wind regime and sea-ice motion. Sea level pressure (SLP) from the NCAR/NCEP Reanalysis is used to create a vorticity metric to investigate the spatial and temporal characteristics of the Beaufort Anticyclone from 1948-2008. Vorticity averaged over the Beaufort Anticyclone region shows the strongest relationship south of Alaska and north of Siberia. The spatial characteristics are investigated further by creating a timeseries of rapid change events, for which SLP changes show similar features south of Alaska and north of Siberia. Temporal characteristics are investigated using running means and spectral analysis, which show an annual cycle and greater energy in lower frequencies than in higher frequencies. The Beaufort Anticyclone vorticity metric is correlated with teleconnection index values. Pacific Ocean patterns such as the Pacific Decadal Oscillation and El Niño show a larger influence than the Atlantic patterns, contrary to past studies that show the Arctic Oscillation as a main driver over the Arctic. Correlations with the other teleconnection indices show considerable seasonality. For example, a significant correlation is found with the Pacific North American pattern in all seasons except summer.