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Ryan L. Fogt, Megan E. Jones, Chad A. Goergens, Susan Solomon, and Julie M. Jones
Open access
Ryan L. Fogt, Megan E. Jones, Susan Solomon, Julie M. Jones, and Chad A. Goergens

Abstract

The meteorological conditions during the Amundsen and Scott South Pole expeditions in 1911/12 are examined using a combination of observations collected during the expeditions as well as modern reanalysis and reconstructed pressure datasets. It is found that over much of this austral summer, pressures were exceptionally high (more than two standard deviations above the climatological mean) at both main bases, as well as along the sledging journeys, especially in December 1911. In conjunction with the anomalously high pressures, Amundsen and his crew experienced temperatures that peaked above –16°C on the polar plateau on 6 December 1911, which is extremely warm for this region. While Scott also encountered unusually warm conditions at this time, the above-average temperatures were accompanied by a wet snowstorm that slowed his progress across the Ross Ice Shelf. Although January 1912 was marked with slightly below-average temperatures and pressure, high temperatures and good conditions were observed in early February 1912, when Scott and his companions were at the top of the Beardmore Glacier. When compared to the anomalously cold temperatures experienced by the Scott polar party in late February and March 1912, the temperature change is in the top 3% based on more than 35 years of reanalysis data. Scott and his companions therefore faced an exceptional decrease in temperature when transiting to the Ross Ice Shelf in February and March 1912, which likely made the persistent cold spell they experienced on the Ross Ice Shelf seem even more intense by comparison.

Open access
Megan E. Jones, David H. Bromwich, Julien P. Nicolas, Jorge Carrasco, Eva Plavcová, Xun Zou, and Sheng-Hung Wang

Abstract

Temperature trends across Antarctica over the last few decades reveal strong and statistically significant warming in West Antarctica and the Antarctic Peninsula (AP) contrasting with no significant change overall in East Antarctica. However, recent studies have documented cooling in the AP since the late 1990s. This study aims to place temperature changes in the AP and West Antarctica into a larger spatial and temporal perspective by analyzing monthly station-based surface temperature observations since 1957 across the extratropical Southern Hemisphere, along with sea surface temperature (SST) data and mean sea level pressure reanalysis data. The results confirm statistically significant cooling in station observations and SST trends throughout the AP region since 1999. However, the full 60-yr period shows statistically significant, widespread warming across most of the Southern Hemisphere middle and high latitudes. Positive SST trends broadly reflect these warming trends, especially in the midlatitudes. After confirming the importance of the southern annular mode (SAM) on southern high-latitude climate variability, the influence is removed from the station temperature records, revealing statistically significant background warming across all of the extratropical Southern Hemisphere. Antarctic temperature trends in a suite of climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are then investigated. Consistent with previous work the CMIP5 models warm Antarctica at the background temperature rate that is 2 times faster than that observed. However, removing the SAM influence from both CMIP5 and observed temperatures results in Antarctic trends that differ only modestly, perhaps due to natural multidecadal variability remaining in the observations.

Open access