Field Validation of Two Boundary Layer Optical Turbulence Models over Desert Surfaces

Author(s):

Sean G. O’Brien, Jeffrey O. Johnson, and Gordon A. MacDonald

Abstract:

The plan and preliminary results for a comparison of two methods for computing optical turbulence strength C_n² at a near-surface reference level are presented. Both methods use measurements of wind speed, temperature, air pressure, and specific humidity at two closely spaced levels in the atmospheric surface layer to determine the Monin–Obukhov length at the reference level and to then determine the value of C_n² through similarity theory. The two-level approach lends itself to rapid field evaluation of optical turbulence vertical profiles in the surface layer that are critical for estimation of scintillation and beam wander effects in free-space optical communication and high-energy laser propagation models.