S105 Surface Ice Melt Driven by Föhn-Like Winds at the Base of the Transantarctic Mountains

Sunday, 10 January 2016
Hall E ( New Orleans Ernest N. Morial Convention Center)
Nicholas James Morgan, University of Tennessee at Martin, Martin, TN; and D. C. Karmosky

The Transantarctic Mountains are responsible for splitting the continent of Antarctica into two halves, the East and West. West Antarctica has experienced one of the largest temperature increases on Earth over the last few decades, thus the need to understand the climate dynamics of Antarctic has become increasingly more urgent. This work focuses on determining melt events occurring at the base of the Transantarctic Mountains at the southernmost ice shelf in the world—Ross Ice Shelf. It has been observed that abnormal melt events in Antarctica have been occurring along the base of the Transantarctic Mountains. These events are thought to be generated by adiabatic warming as air descends roughly three kilometers from the Antarctic Plateau to the ice shelf, similar to Föhn winds in Alpine environments. Föhn winds are warm, dry, downslope winds that occur on the leeward side of a mountain and in these case studies air is forced downward by a pressure gradient between the Antarctic Plateau and a polar low in the Ross Sea causing a similar rise in temperatures. The surface melt extent on Ross Ice Shelf was examined over a 27-year time period (1987-2014) and separated into three separate case studies. These three case ice-melt case studies meet the qualifications that they could be caused by Föhn-like winds. By using NCEP/NCAR reanalysis, weather patterns associated on near the base of the Transantarctic Mountains to determine if the cause of surface melt is caused by Föhn-like winds. Factors that are examined are vector winds, surface temperatures, temperatures at 850mb heights, and relative humidity.
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