Climate modes in southern high latitudes and their impacts on Antarctic sea ice

Abstract

This study investigates the influence of high-latitude climate variability on the Antarctic sea ice distribution. The climate variability examined here includes distinct climate modes, such as the Southern Annular Mode (SAM), quasi-stationary wave-3 pattern, Pacific South American pattern (PSA) and Semi-Annual Oscillation (SAO). The results reveal that the largest impact comes from PSA in the Antarctic Dipole (ADP) region of the western hemisphere at the interannual timescale, which is related to the teleconnection of El Niño-Southern Oscillation (ENSO). The wave-3 pattern also has a strong and similar influence on sea ice in the ADP regions as PSA does, suggesting a positive interaction between PSA and wave-3 in the region. Measured by correlation coefficients and their significance, SAM has a relatively less significant influence on sea ice than other climate patterns in general, though this global assessment may not apply to particular regions. Sea ice usually responds to large-scale atmospheric anomalies with a 2-month delay. The singular value decomposition (SVD) analysis reveals that the coupled relationships between sea ice and atmospheric pressure, temperature, and wind fields are represented by these known climate modes. The leading coupled modes between sea ice and sea level pressure are accountable for 50% to 60% of total squared covariance for all seasons. The leading modes between sea ice and surface air temperature in winter and summer are also accountable for the same amount of total squared covariance. It indicates that these well-established climate modes/patterns are the dominant factors leading to a strong interaction between the atmosphere and sea ice field in the Antarctic. Copyright 2008 by the American Geophysical Union.