Mesoscale optical turbulence simulations above Dome C, Dome A and South Pole

Abstract

In two recent papers, the mesoscale model Meso-NH, jointly with the Astro-Meso-NH package, has been validated at Dome C, Antarctica, for the characterization of optical turbulence. It has been shown that the meteorological parameters (temperature and wind speed, on which the optical turbulence depends) as well as the C 2 N profiles above Dome C were correctly reproduced statistically. The three most important derived parameters that characterize the optical turbulence above the Internal Antarctic Plateau -the surface-layer thickness, the seeing in the free atmosphere and the seeing in the total atmosphere -were shown to be in very good agreement with observations. Validation of C 2 N has been performed using all the measurements of the optical turbulence vertical distribution obtained in winter so far. In this paper, in order to investigate the ability of the model to discriminate between different turbulence conditions for site testing, we extend the study to two other potential astronomical sites in Antarctica: Dome A and South Pole, which we expect to be characterized by different turbulence conditions. The optical turbulence has been calculated above these two sites for the same 15 nights studied for Dome C and a comparison between the three sites has been performed. The ability of the Meso-NH model to discriminate between different types of optical turbulence behaviour is confirmed, and it is evident that the three sites considered have different characteristics as regards the seeing and the surface-layer thickness.

Characterization of the boundary layer at Dome C (East Antarctica) during the OPALE summer campaign

“…Dome C is an area where observation and modelling of the boundary layer have already been performed due to its particular location (Swain and Gallée, 2006;Sadibekova et al, 2006;King et al, 2006;Gallée and Gorodetskaya, 2010;Genthon et al, 2010Genthon et al, , 2013Brun et al, 2011;Lascaux et al, 2011;Argentini et al, 2013;Pietroni et al, 2014). Furthermore, Dome C was recently selected as the test site for the next Gewex Atmospheric Boundary Layer Studies (GABLS4) model intercomparison (see http://www.…”

“…Short-term meteorological simulations have already been done over Dome C with a coupled atmospheresnow model, focusing on the behaviour of the snow model (Brun et al, 2011). Long-term simulations of the Antarctic climate have also been done, with a focus on their behaviour at Dome C. Swain and Gallée (2006) and Lascaux et al (2011) used respectively the limited area models MAR (without any reinitialization of meteorological variables) and Meso-NH to compare the optical properties of the atmosphere at Dome C with those of other potential Antarctic sites for astronomical observations using a large telescope. Gallée and Gorodetskaya (2010) validated MAR for winter conditions, emphasizing the difficulty in accurately simulating the downward long-wave radiation and proposing to include the influence of small airborne snow particles in the parameterization of the radiation transfer.…”

Variable Stars Observed in the Galactic Disk by AST3-1 from Dome A, Antarctica

“…The Antarctic plateau offers a number of unique advantages for precision, ground-based, time-domain as-tronomy, such as the ability to observe continuously during winter, low scintillation noise, excellent seeing above a very low boundary layer, low airmass variations, low aerosols, low water vapor, more stable atmospheric transmission, wider wavelength windows, and a dark sky in the infrared (Lawrence et al 2004(Lawrence et al , 2006(Lawrence et al , 2008Moore et al 2008;Kulesa et al 2008;Aristidi et al 2009;Burton 2010;Zou et al 2010;Yang et al 2010;Sims et al 2010;Bonner et al 2010;Lascaux et al 2011;Tremblin et al 2011;Pei et al 2011Pei et al , 2012Sims et al 2012a,b;Giordano et al 2012;Storey 2013;Hu et al 2014;Ashley 2013;Yang et al 2016). There is thus considerable interest in overcoming the technical challenges of operating in Antarctica, so that the advantages for astronomy can be realized (Tothill et al 2008;Kulesa et al 2008;Crouzet et al 2010;Chapellier et al 2016;Mékarnia et al 2016).…”

Monitoring the optical turbulence in the surface layer at Dome C, Antarctica, with sonic anemometers

“…Similar properties were found at these locations, in particular this thin SL which gives access to the free atmosphere seeing at elevations of a few tens of meters above the ground. This is also supported by numerical simulations by (Swain & Gallée (2006); Hagelin et al (2008); Lascaux et al (2009Lascaux et al ( , 2010Lascaux et al ( , 2011. Therefore the characterization of the SL, both in terms of intensity and vertical structure, is critical to the determination of methods to compensate its effects (Travouillon et al (2009) ;Carbillet et al (2010).…”