Recent variations in mean temperature and the diurnal temperature range in the Antarctic

Abstract

Monthly mean surface temperature data are available from nearly twenty stations for the period since the International Geophysical Year 1957. All but three stations show an increase in mean temperatures over this time, amounting in the average to 0.57°C over 1957 to 1994. All of this warming occurred before the early 1970s. Since then, there has been no change. The warming has been greatest in the Antarctic Peninsula. Analyses of the less‐widely available diurnal temperature range (DTR) (maximum‐minimum) data show regions of increase and decrease over Antarctica. An average continental DTR series shows no trend over 1957 to 1992. Analyses for six mid‐to‐high latitude Southern Ocean islands show increases in mean temperature over 1961–90. Given the low year‐to‐year variability in these data, these trends are more significant than for any of the stations on the Antarctic continent. The marked decrease in mean temperatures over Antarctica during 1993 and 1994 seems unrelated to sea‐ice variations which show little change since the early 1980s.