Sensitivity of the Receiver Coherence Diameter and Modulation Transfer Functionto Variations of a Damp Unstable Atmosphere

摘要

The purpose of this study was to examine the sensitivity of the receivercoherence diameter, r sub o, and the modulation transfer function (MTF) to variations of the natural atmosphere from an assumed ideal average state and from misrepresentation of the atmospheric effects due to errors in measurement and processing of the basic meteorological parameters. The concept was simplified by assuming that all natural variations and errors due to sensor performance and positioning can be lumped and that collectively are normally distributed, even though the natural variations are known not to be normal. For this study, the authors selected two sets of data to analyze. The data from Davis, California, were collected during unstable conditions with clear skies. Bar graphs were used to show distributions resulting from total errors. They include the friction velocity u*; windspeed V sub r; temperature scaling parameter T*; specific humidity scaling parameter q*; Obukhov scaling length L; structure parameter (C sub n)sq.; and receiver coherence diameter r sub o. Additionally, the authors take the minimum, maximum, and mean r sub o for each case and plot the resulting near and far-field slow MTF. Optics, Receiver coherence diameter, Optical turbulence, Modulation transfer functions.