Antarctic warming? Insight from a new near-surface temperature reconstruction from 1960-2010

Aside from the rapid warming in the Antarctic Peninsula, the magnitude, spatial patterns and seasonality of the long-term changes in Antarctic near-surface temperatures are still debated. Spurious trends in current global reanalysis datasets make them unfortunately inapplicable to such investigation. As a result, several attempts have been made in recent years to reconstruct Antarctic temperatures spatially and temporally using statistical methods applied to the sparse network of available observations.

Here, we present the results from a kriging-based reconstruction of monthly near-surface temperatures in Antarctica from 1960-2010. Our method uses monthly temperature observations from a fixed network of 15 Antarctic stations. The spatial relationships between these temperature records and the rest of the Antarctic continent are estimated from the ERA-Interim reanalysis during the 1989-2010 period. Our method devotes particular attention to the temperature time series at Byrd Station, the only long-term record in West Antarctica, which contains large temporal gaps and has itself to be reconstructed from observations from nearby stations and other observational sources. The resulting regional distribution of annual and seasonal temperature trends from our reconstruction are discussed, contrasted with previous results and related to changes in the atmospheric circulation.