Extreme intra-seasonal anomalies in the Amundsen and

• Main Authors: Fabio Ullmann, Furtado Lima, Leila M. Véspoli De Carvalho
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Bellingshausen Sea; Antarc*; Antarctica; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.429.4141; http://www.igsoc.org/annals/48/a48a020.pdf

ABSTRACT. We examine the role of the propagation of atmospheric mid-latitudes wave trains in modulating the Amundsen and Bellingshausen sea-ice area (SIA), Antarctica, on intra-seasonal timescales (20–100 days). Spectral analysis of passive microwave estimates of SIA in the Amundsen and Bellingshausen Seas for 1979–2004 shows significant peaks on intra-seasonal timescales. Previous studies have suggested that variations in SIA are linked to disturbances in atmospheric circulation and sea surface temperature. We show that extreme SIA anomalies on intra-seasonal timescales lag the propagation of subtropical wave trains in the Southern Hemisphere by approximately 10–15 days. The sign of the SIA anomaly depends on the phase of the wave. We present evidence that the number of disturbances that cause extreme anomalies of SIA on intra-seasonal timescales has increased in the last 14 years. 1.