Study of the winter 2005 Antarctica polar vortex

TL;DR

This study investigates the position of the minimum high-altitude wind speed within the Antarctic polar vortex during winter 2005 to understand its relation to site location and implications for optical turbulence.

Contribution

It confirms the hypothesis that wind speed minima are related to the distance from the vortex center, aiding astronomical site selection.

Findings

Wind speed minima are located relative to the vortex center.

Site proximity to vortex center influences wind speed strength.

Results support the hypothesis linking wind speed to vortex position.

Abstract

During winter and springtime, the flow above Antarctica at high altitude (upper troposphere and stratosphere) is dominated by the presence of a vortex centered above the continent. It lasts typically from August to November. This vortex is characterized by a strong cyclonic jet centered above the polar high. In a recent study of our group (Hagelin et al., 2008) of four different sites in the Antarctic internal plateau (South Pole, Dome C, Dome A and Dome F), it was made the hypothesis that the wind speed strength in the upper atmosphere should be related to the distance of the site to the center of the Antarctic polar vortex. This high altitude wind is very important from an astronomical point of view since it might trigger the onset of the optical turbulence and strongly affect other optical turbulence parameters. What we are interested in here is to localize the position of the minimum value of the wind speed at high altitude in order to confirm the hypothesis of Hagelin et al. (2008).