HR: 17:00h
AN: GC44A-05    [Abstracts]
TI: Antarctic Peninsula Climate Response to Atmospheric Circulation Variability: Evidence for Contrasting Controls in Winter and Summer
AU: * King, J C
EM: jcki@bas.ac.uk
AF: British Antarctic Survey, High Cross Madingley Road, Cambridge, CB3 0ET United Kingdom
AB: Over the past 50 years the west coast of the Antarctic Peninsula has warmed more rapidly than any other region on Earth and the Peninsula as a whole has warmed faster than other regions of Antarctica. There have been significant changes in the regional cryosphere and ecosystems associated with this warming, most notably the rapid collapse of some of the ice shelves that used to border the Peninsula. Temperature records from Antarctic Peninsula climate stations were used together with atmospheric reanalyses to test the hypothesis that the regional warming is driven by atmospheric circulation changes. Winter temperatures, particularly along the southern parts of the west coast, are strongly correlated with the strength of the Pacific South American (PSA) teleconnection pattern, itself influenced by conditions in the tropical Pacific. By contrast, summer temperatures in the northern and eastern parts of the region are closely related to an index of the Southern Hemisphere Annular Mode (SAM), which is a measure of the strength of the circumpolar westerlies. Recent studies have demonstrated that there has been a positive trend in the SAM index (strengthening westerlies) over the past few decades, which is largely attributable to increases in greenhouse gases. The summer warming of the Peninsula is thus likely to have an anthropogenic component. However, attribution of winter temperature trends in the Peninsula remains problematical as the links between anthropogenic forcing and changes in the PSA pattern have not been well established.
DE: 9310 Antarctica
DE: 3349 Polar meteorology
DE: 3309 Climatology (1620)
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting