Spatio-temporal changes in surface air temperature in the region of the northern Antarctic Peninsula and south Shetland islands during 1950–2003

Time series of surface air temperature recorded at eight stations upon the northern Antarctic Peninsula and South Shetland Islands were analyzed for the period 1971–2000 (longer time series were analyzed for some of the stations). Erroneous values and inhomogeneities were searched for. After homogenization, missing data were replaced by interpolated values. Monthly, seasonal, and annual trends in surface air temperature were analyzed, and their statistical significance calculated. Spatial variability in surface air-temperature trends was determined and three distinct regions identified: a southern region (Vernadsky, Rothera), eastern region (Esperanza, Marambio), and northern region (Bellingshausen, Prat, Frei, O'Higgins).Different trends in temperature were obtained for the eastern and western coasts of the Antarctic Peninsula, despite the close vicinity of the stations. The surface air temperature on the northern coast (O'Higgins) and in the northern region shows the smallest changes in temperature. The lowest surface air temperature and greatest warming trends during 1971–2000 were recorded on the eastern coast (Marambio and Esperanza) in autumn. The analyses confirm a warming trend (except for spring) at some stations. The most pronounced increasing seasonal trend was found in winter (five stations), followed by autumn (three stations). This warming is probably related to changes in atmospheric circulation, the extent of sea ice, and ocean processes.