Atmospheric Scintillation Measurements With A Transmissometer

Abstract

A transmissometer that operates in the visible /near IR region of the spectrum has been modified to measure beam modulation caused by turbulence along a 300 meter path. The system measures both total transmission and the rms value of the intensity fluctuations and has been designed to allow variation of aperture size and optical wavelength. From these measurements, aI2, QX2 and Cn2 are calculated and compared with measurements made with a log-amplitude variance scintillometer.All measurements have been made over a near -ground horizontal path and are compared with the NOAA model that predicts intensity fluctuations based on Cn2, wavelength, and aperture size.