How good an estimator of turbulence strength is C_n² at the boundary layer?

The Obukhov-Kolmogorov (OK) theory has provided us with the very well-known −11/3-power spectrum; widely assumed as a valid model for the refractive index fluctuations in the whole atmosphere. Within its reach, the strength of the fluctuations are conveyed by the structure constant, C_n². Yet, the OK model presupposes the existence of statistical isotropy and homogeneity-both for the velocity and refractive index fluctuations. In this work, we show that this is a rare occurrence in turbulent airflow above the ocean. Therefore, we need to re-evaluate the physical meaning of C_n² measurements.