Dome C coherence time statistics from DIMM data. Issue 4 (27th June 2020)

• Record Type: Journal Article
• Authors: Aristidi, E; Agabi, A; Abe, L; Fossat, E; Ziad, A; Mékarnia, D
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 496:Issue 4(2020)
• Page Start: 4822
• Page End: 4826
• Publication Date: 2020-06-27
• Subjects: atmospheric effects -- methods: data analysis -- site testing; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa1862
• Languages: English
• ISSNs: 0035-8711

Abstract

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.