Atmospheric turbulence measurements by angle of arrival fluctuations and intensity scintillations with large aperture

Abstract

Summary form only given. Atmospheric turbulence was measured using a one station scheme, over a flat beach parallel to the Mediterranean sea shore. A diffusive white target situated at a distance of 1500 m was illuminated with a 5 mJ Q-switched Nd:YAG laser beam at a rep-rate of 500 Hz. The laser spot on the target had a diameter of about 0.5 m and the height of the path was 1.2 m. The reflected beam was imaged near the laser by a Cassegrain lens system (f=1000 mm D=91 mm) onto a horizontal linear array detector with eight 50/spl times/250 /spl mu/m (width/spl times/height) elements. At the same time the system measures cross wind speeds, this is reported elsewhere. This scheme was used to measure the turbulence based on two separate principles. The first is based on the intensity scintillations measured on the detectors. The second principle is based on the angle of arrival (AOA) fluctuations of the beam, measured on the detector array as a linear displacement.