Climate variability in the western Antarctic peninsula region

The climate of tile Western Antarctic Peninsula (WAP) region is distinguished by large seasonal and interannual variability and by the occurrence of seasonal sea ice which changes the ocean-atmosphere interface, affects tile surface albedo, and modifies the annual temperature cycle. Air temperature records for several peninsula stations have been examined, and the annual progression of surface air temperatures show an along-peninsula gradient indicative of a contrasting influence of maritime versus continental climatic regimes. WAP temperature records show the largest and most significant warming trends for the Antarctic with mid-winter temperature increases of 3° to 5°C over the past half-century. Increased temperature variability in fall and winter is linked to tile high interannual variability of sea ice coverage. Linear regression analysis shows a significant (99.9%) anti-correlation between air temperature and sea ice extent, even after accounting for serial correlation in the two time series. There are distinct seasonal lead/lag relationships between temperature and sea ice in this region, which underscore the complexity of polar feedback mechanisms. The more than 45 year Faraday air temperature record shows a significant (95% confidence level) correlation with the Southern Oscillation Index (SOI) and coherences between both temperature and sea ice with the SOI suggest teleconnections between the WAP and lower latitudes. This evidence suggests that the WAP area, the focus of the Palmer Long-Term Ecological Research program, is sensitive to climate variability. Consequently, because of strong coupling between temperature, sea ice and the antarctic marine ecosystem, the Palmer LTER is ideally located for the study of ecological responses to global change.