Mysterious Mesospheric Bores Over the South Pole

• Main Author: Solorio, Christina
• Format: Text
• Language: unknown
• Published: Hosted by Utah State University Libraries 2016
• Subjects: South Pole; mesospheric bores; Antarctic polar vortex; gravity waves; Physics; Amundsen Scott South Pole Station; Amundsen-Scott; Amundsen-Scott South Pole Station; Antarctic; Antarc*; South pole
• Online Access: https://digitalcommons.usu.edu/phys_capstoneproject/41; https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1042&context=phys_capstoneproject

Abstract. During the winter‐time, the South Pole lies at the center of the giant Antarctic polar vortex which isolates it from the rest of the world. Over the past four years, USU has successfully operated an infrared camera at the US Amundsen‐Scott South Pole Station to investigate dynamics of atmospheric gravity waves within the vortex. Gravity waves are generated when a force disturbs an air packet and buoyant and gravitational forces in turn cause it to oscillate. While gravity waves in general are ubiquitous in the atmosphere, propagating well into the mesosphere and lower thermosphere region (~80‐100 km), one rare type of gravity wave known as a “bore” is characterized by a sharp leading front followed by several distinct trailing waves that grow in number. Bore wave events are observed in tropospheric clouds, but to date observations are rare in the upper atmosphere, especially at high‐latitudes. In this study ranging over 4 winter seasons (April‐August 2012‐2015), we have discovered a surprisingly large number of bores (83 events). Examples of these events are presented together with measurements of their propagation characteristics. These results provide important new information on the generation and propagation of gravity waves within the winter polar vortex.