An analysis of temperatures and wind speeds above Dome C, Antarctica

Abstract

Abstract.A good astronomical site must fulfill several criteria including low atmospheric turbulence and low wind speeds. It is therefore important to have a detailed knowledge of the temperature and wind conditions of a location considered for future astronomical research. Antarctica has unique atmospheric conditions that have already been exploited at the South Pole station. Dome C, a site located on a local maximum of the Antarctic plateau, is likely to have even better conditions. In this paper we present the analysis of two decades of wind speed measurements taken at Dome C by an automated weather station (AWS). We also present temperature and wind speed profiles taken over four Antarctic summers using balloon-borne weather sondes. We will show that as well as having one of the lowest average wind speed ever recorded at an existing or potential observatory, Dome C also has an extremely stable upper atmosphere and a very low inversion layer.

Vertical profile of the specific surface area and density of the snow at Dome C and on a transect to Dumont D'Urville, Antarctica – albedo calculations and comparison to remote sensing products

“…Grenfell et al (1994) justify the presence of the thin high-SSA layer at the top of the snow pack by wind action, suggesting that small particles will settle last after a wind event. Even if this is indeed the case, which we cannot judge here, it is not certain that this process would be as frequent at Dome C, which is significantly less windy than South Pole (Aristidi et al, 2005). Furthermore, errors in measurements of albedo, SSA, density and layer thickness and in modeling (DISORT does make approximations, in particular for directional viewing) are at least 20 %, so that comparing data obtained in two widely different settings is difficult.…”

Site testing in summer at Dome C, Antarctica

“…The first winterover also began this year. 197 meteorological balloons were successfully launched and corresponding results were published in Aristidi et al (2005). Major conclusions are that the wind speed profiles in Dome C appear as the most stable among all the astronomical sites ever tested, and that the major part of the atmospheric turbulence is probably generated in the first 100 m above the snow surface, where the temperature gradients are the steepest (around 0.1…”

On the atmosphere for astronomers above Dome C, Antarctica

“…The DIMM instruments showed a regular deterioration of the ground based seeing quality with the decreasing winter temperature. On the other hand 30 radio-sounding during the dark time have shown a ground inversion layer that is very turbulent, with a thickness of 20-50 m (Agabi et al 2006) During the four previous summers (mid-November to early February), 200 meteorological balloons equipped with standard meteo radiosondes were been launched (Aristidi et al 2005b). They provide the following parameters: altitude, temperature, pressure, humidity, wind speed and direction, up to altitudes generally between 20 and 25 km, and sometimes slightly higher.…”