NCAR: Study Indicates a Net Warming Trend for the Southernmost Continent

Eric Steig and Antarctic Temperature Map

Top: Eric Steig / University of Washington
Bottom: Antarctica / NASA/GSFC Scientific Visualization Studio.

1/12/2010

Until recently, the Antarctic ice sheet looked to be bucking the global warming trend. This assessment relied on temperature data collected from a sparse network of mostly coastal weather stations.

To provide a more complete picture of Antarctica’s historic surface temperature regime, a team of U.S. scientists employed an innovative technique to construct 50-year estimates of the near-surface temperature anomalies for the entire continent.

The resulting climate field reconstructions for 1957-2006 show an overall warming trend across Antarctica, with this trend being strongest over the West Antarctic ice sheet.

Funded by the National Science Foundation’s Office of Polar Programs and led by Eric Steig, a glaciologist and isotope geochemist at the University of Washington, the team based their temperature reconstructions on observations collected at manned weather stations; temperature data from these stations are the continent’s most reliable and continuous records, extending back to 1957.

However, these observations are available at only a handful of locations, with all but two located on the coast, making it difficult to assess temperatures across the vast continent.

To obtain more information about the continental interior, the scientists used two independent sources of data, thermal infrared (IR) measurements from satellites and observations from automatic weather stations (AWS) located in remote parts of the continent and near research bases.

The thermal IR and AWS data, which extend from approximately 1980 to present, provide information about the spatial relationships of temperature anomalies between regions.

The researchers then applied these spatial relationships to the long-term manned temperature records to fill in the areas between stations, resulting in an Antarctic-wide temperature time-line that stretches back to 1957.

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