Amplitude, Scale, and Spectrum of Refractive Index Inhomogeneities in the First 125 Meters of the Atmosphere

An extensive series of observations was obtained with two refractometers and meteorological equipment installed on various levels of a 128-meter tower at the Brookhaven National Laboratory, Long Island, New York. One of the refractometers was equipped with a multiple cavity unit for the study of correlation between two positions in the horizontal direction. The errors arising from the exposure of the cavity to the atmosphere and its ventilation were investigated. The amplitude of the refractive index variations could be correlated with various meteorological conditions. From the experimentally determined cross-correlation coefficient, and assuming that its variation with distance is given by the exponential (Taylor) form, scales in the neighborhood of 60 meters were obtained. A crude analysis of the data indicated that the intensity of the refractive index inhomogeneities varied, on the average, as the 1.6 power of their size.