Journal of Geophysical Research: Atmospheres

Cover image for Vol. 121 Issue 17

Impact Factor: 3.318

ISI Journal Citation Reports © Ranking: 2015: 27/184 (Geosciences Multidisciplinary)

Online ISSN: 2169-8996

Associated Title(s): Journal of Geophysical Research

Ross Ice Shelf air stream driven by polar vortex cyclone

The powerful air and ocean currents that flow in and above the Southern Ocean, circling in the Southern Hemisphere's high latitudes, form a barrier to mixing between Antarctica and the rest of the planet. Particularly during the austral winter, strong westerly winds isolate the Antarctic continent from heat, energy, and mass exchange, bolstering the scale of the annual polar ozone depletion, and driving the continent's record-breaking low temperatures. Pushing through this wall of high winds, the Ross Ice Shelf air stream (RAS) is responsible for a sizeable amount of mass and energy exchange from the Antarctic inland areas to lower latitudes. Sitting due south of New Zealand, the roughly 470,000-square-kilometer Ross Ice Shelf is the continent's largest ice shelf and a hub of activity for Antarctic research. A highly variable lower atmospheric air current, RAS draws air from the inland Antarctic Plateau over the Ross Ice Shelf and past the Ross Sea. Drawing on modeled wind patterns for 2001-2005, Seefeldt and Cassano (2012) identify the primary drivers of RAS. In their analysis of the 150-meter altitude wind field, the authors identified the northward flow of RAS. They found that RAS was more prevalent in winter than summer, and that it was most common when there was an atmospheric cyclone over the Ross Sea. The authors suggest that the primary driver for RAS is the pressure gradient established by such atmospheric cyclones.

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