Investigation of Optical Turbulence in the Coastal Environment over False Bay / South Africa

Optical turbulence in the atmosphere is characterized by the structure function parameter of the refractive index C_n², a key parameter in describing the atmospheric influence on wave propagation (e.g. for laser or optical communication). The optical turbulence was investigated during the FESTER (First European South African Transmission Experiment) experiment from June 2015 to February 2016, in the False Bay area near Cape Town (South Africa). C_n² was measured with different techniques at fixed points offshore, as well as over two optical paths over water, along and perpendicular to the coast, yielding integrated path measurements in the atmospheric surface layer. The data were analysed with respect to coastal effects, meteorological conditions and water temperature. The experimental data were compared to modelling efforts. The height dependency of the optical turbulence and the impact of local phenomena on the behaviour of optical turbulence are presented and discussed.