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, 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 τ0 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 τ0 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.
@article{arxiv.2006.13778,
title = {Dome C coherence time statistics from DIMM data},
author = {E. Aristidi and A. Agabi and L. Abe and E. Fossat and A. Ziad and D. Mékarnia},
journal= {arXiv preprint arXiv:2006.13778},
year = {2020}
}