Seasonal Patterns of Air Surface Temperature and Pressure Change in Different Regions of Antarctica

Abstract

In the context of global warming, increases in Antarctic surface air temperatures are expected, and have been found to be larger than in lower latitudes, both from modelling experiments and analysis of instrumental records. Nevertheless, Antarctic warming has not been evenly spread through the seasons or regionally. In this paper, we identify different regional responses to changes in temperature and pressure through the comparison of daily air surface temperature and pressure for two periods 1957–1973 (PI) and 1979–1995 (P2) for four Antarctic Stations (Faraday, Mawson, Halley and South Pole). These stations are characterised respectively with Antarctic Oceanic Climate, Ice Shelf Climate, Antarctic Katabatic Climate and Cold Continental Climate of the Eastern Plateau, four of the eight climatic types described for Antarctica by a multivariate analysis of the output of NCEP/NCAR Reanalyses (Aguilar, 2000).

Dramatic differences are found in the evolution of air temperatures and air pressures at these meteorological stations and, by extension, in their climatic regions. The Antarctic Western Coast (here studied through Faraday and Halley stations) shows a strong and significant warming in winter and summer and no increases in the transition seasons. In contrast, the Antarctic Eastern Coast and the Antarctic Eastern Plateau (here represented by Mawson and South Pole respectively) show a slight but significant cooling, centred on the early winter period. The close relationship of variations in air temperature to changes in air pressure suggests a key role is played by changes in atmospheric circulation and induced effects like modification of sea-ice extents. An uneven response in temperature variations is evident, heavily dependent on regional topography and the different seasons of the year.