RECENT TRENDS IN NEAR-SURFACE AIR TEMPERATURE IN ANTARCTICA FROM REANALYSYS AND STATION DATA

Abstract

This study utilizes monthly-mean records of near-surface air temperature from ground-based stations in Antarctica spanning the time period of 1980 to 2022 to estimate temperature trends in the region. Analysis of in situ data confirms the prevailing warming tendencies over the continent, with positive trends observed at 11 out of the 18 examined stations. Annual mean temperature trends reach 0.40 °C/decade, with the most significant warming observed in the Antarctic Peninsula, West Antarctica, and Inner Antarctica. Relatively weaker and mixed temperature trends occurred in the coastal areas of East Antarctica. Throughout the year, the spring season exhibited the most consistent upward trends across the continent. Comparing current temperature trends with earlier estimates has revealed increased warming at most Antarctic stations in recent years. Four widely used reanalysis datasets – ERA5, JRA55, MERRA2, and CFSR – were examined to evaluate their ability to reproduce the observed temperature trends in situ. Among these four datasets temperature trends inferred from ERA5 provided the best fit to the station data. However, even in ERA5, the uncertainty in trend estimates was comparable to the magnitude of trend variation between stations. This suggests a limited ability of available reanalysis datasets to accurately reproduce the spatial distribution and patterns of temperature trends across the continent.