Distribution and temporal trends of temperature extremes over Antarctica

The spatiotemporal characteristics of temperature extremes over Antarctica remain largely unknown. Here, we use quality-controlled daily datasets from Antarctic weather stations to show that the annual maximum and minimum temperatures exhibit a decreasing pattern over Antarctica from the coast to inland regions. This feature holds for the warmest daily maximum and coldest daily minimum temperatures, which define the intensity of extremes, but not for the number of warm (cold) days measuring the frequency of extremes, which show limited dependence on latitude or elevation. During 1970-2000, the temperature extremes in the South Orkney islands and on the margins of East Antarctica show opposite trends, especially with a significant increasing and decreasing trend in warm events, respectively. During 1999-2013, the intensity and frequency of extreme temperatures decrease significantly over West Antarctica, but the trends vary greatly across sub-regions of Antarctica. Despite the limited number of stations and the potential time dependence of trends, these results not only help to decipher the climate regimes of Antarctica and fill current gaps in the map of global climate extremes, but also may guide the future design of Antarctic observational networks and be used to assess the capability of reanalysis datasets and climate models.