Atmospheric coherence time (${\tau }_0\sim r_0/v_{\mathrm{eff}}$)

The timescale on which turbulent optical-path fluctuations decorrelate constrains short-exposure imaging and adaptive-optics control latency. In a frozen-flow approximation it scales as $r_0/v_{\mathrm{eff}}$, with an effective turbulence-weighted wind speed. It is not the temporal coherence time set by the optical bandwidth.^[ref]