Dome C coherence time statistics from DIMM data

E. Aristidi (1) , A. Agabi (1) , L. Abe (1) , E. Fossat (1) , A. Ziad (1) , D. Mekarnia (1)

1 LAGRANGE - Joseph Louis LAGRANGE

We present a reanalysis of several years of DIMM data at the site of Dome C, Antarctica, to provide measurements of the coherence time τ 0. Statistics and seasonal behaviour of τ 0 are given at two heights above the ground, 3m and 8m, for the wavelength λ = 500nm. We found an annual median value of 2.9ms at the height of 8m. A few measurements could also be obtained at the height of 20m and give a median value of 6ms during the period June-September. For the first time, we provide measurements of τ 0 in daytime during the summer, which appears to show the same time dependence as the seeing with a sharp maximum at 5pm local time. Exceptional values of τ 0 above 10ms 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.

Domaines: Astrophysique [astro-ph]

E. Aristidi, A. Agabi, L. Abe, E. Fossat, A. Ziad, et al.. Dome C coherence time statistics from DIMM data. Monthly Notices of the Royal Astronomical Society, 2020, ⟨10.1093/mnras/staa1862⟩. ⟨hal-02890504⟩