Article

• Main Authors: H Ere, West Antarctic, Peninsula Extreme
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Antarc*; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.460.6758; http://www.vliz.be/imisdocs/publications/231059.pdf

[i] In September-October 2005, the juxtaposition of low- and high-pressure anomalies at 130°W and 60°W, respectively, created strong and persistent northerly airflow across the West Antarctic Peninsula (WAP). This had a major impact on regional sea ice conditions, with extreme ice compaction in the Bellingshausen and East Amundsen seas (60°W—130°W) but divergence in the West Amundsen and East Ross seas. This resulted in the former in a highly compact marginal ice zone and ice cover, mean modeled ice thicknesses of>5 m, and an earlier-than-average maximum extent (mid-August). While rapid ice retreat in late winter-spring created a major negative ice extent anomaly, compact ice persisted in the subsequent summer. Other effects were anomalies in air temperature (of +1°C to +5°C) and precipitation rates (to>2.5 mm/d). The patterns in late 2005 are consistent with the occurrence of a weak La Niña and a near-neutral Southern Annular Mode, with a quasi-stationary zonal wave three pattern dominating hemispheric atmospheric circulation. Once a compact ice edge was created, it took only one additional week of strong winds to “ solidify ” the pack in place. Conditions in 2005 are analyzed in the context of 1979—2005 and compared with the springs of 1993, 1997, 1999, 2001