Dome C coherence time statistics from DIMM data

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Aristidi, E, Agabi, A, Abe, L, Fossat, E, Ziad, A, Mékarnia, D
• Other Authors: IPEV, Centre National de la Recherche Scientifique
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2020
• Subjects: Space and Planetary Science; Astronomy and Astrophysics; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1093/mnras/staa1862; http://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/staa1862/33437688/staa1862.pdf; http://academic.oup.com/mnras/article-pdf/496/4/4822/33503891/staa1862.pdf

ABSTRACT We present a reanalysis of several years of DIMM data at the site of Dome C, Antarctica, to provide measurements of the coherence time τ0. Statistics and seasonal behaviour of τ0 are given at two heights above the ground, 3 and 8 m, for the wavelength λ = 500 nm. We found an annual median value of 2.9 ms at the height of 8 m. A few measurements could also be obtained at the height of 20 m and give a median value of 6 ms during the period June–September. For the first time, we provide measurements of τ0 in daytime during the summer, which appears to show the same time dependence as the seeing with a sharp maximum at 5 pm local time. Exceptional values of τ0 above 10 ms are met at this particular moment. The continuous slow variations of turbulence conditions during the day offers a natural test bed for a solar adaptive optics system.