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Optical and radio frequency refractivity fluctuations from high resolution point sensors [electronic resource] : sea breezes and other observations /

by MacPherson, Douglass A.; School (U.S.), Naval Postgraduate

Abstract (Summary)
High bandwidth communications and optical/RF weapons systems are being developed that are limited by atmospheric absorption and accumulated phase distortions. The need and ability to mitigate these effects depends on the magnitudes of the atmospheric perturbations. The optical and RF index of refraction structure function parameters, Cn 2, are examined simultaneously using field data. It is difficult to model the magnitudes of Cn 2, accurately and values produced by models are frequently off by an order of magnitude or more. In situ measurements of Cn 2 are extremely sparse at RF wavelengths and limited to a few field studies. To refine models or conduct climatologically studies for Cn 2 requires direct measurements to identify the underlying factors that produce the fluctuations and provide a clear understanding of the phenomena. This thesis utilized high speed measurements of the atmospheric humidity, temperature and wind speed collected on a tower 10 m above ground level at a coastal location. The humidity data were collected with a high speed infrared humidity sensor. A three axis sonic anemometer provided the wind fluctuation data and a fine wire temperature sensor as well as the sonic anemometer provided atmospheric temperature. All the data were sampled at 20 Hz. This study examined a subset of 251 days of data collected at the Marina, California airport to determine the relative variations of the optical and RF magnitudes of Cn 2 and the underlying atmospheric phenomena that produced the results.
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School:The United States Naval Postgraduate School

School Location:USA - California

Source Type:Master's Thesis

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