CO2 coherent propagation (with reciprocal tracking) through the marine boundary layer. Experimental measures of attenuation, scintillation, wavefront, tilt, and coherence are made through clear air, fog, and haze

Two CO2 heterodyne receivers, each utilizing wave-front tilt tracking derived from the nutation of the received signal over the detector, are used to measure propagation effects through a marine environment over an 18.2-km path across the San Diego harbor inlet. Measurements of attenuation, characterized as signal loss; scintillation, characterized as percent modulation; wavefront tilt, characterized as angle-of-arrival spectra; and coherence, characterized by the angular brightness function, are made through clear air, haze, and fog. It is determined that reciprocal tracking provides significant enhancement to signal levels under all propagation conditions whereas single-station tracking does not. The dominance of a theoretically predicted coherent direct beam propagating through scattering media is observed. The data are correlated with meteorological data obtained from three points along and adjacent to the path.