REMOTE-SENSING OF ATMOSPHERIC-TURBULENCE AND TRANSVERSE WINDS FROM WAVE-FRONT SLOPE MEASUREMENTS FROM CROSSED OPTICAL PATHS

In the theory of atmospheric turbulence, the strength of the spatial v ariations of the index of refraction n is proportional to a parameter known as the atmospheric-structure constant. The atmospheric-structure constant is denoted C(n)2(z) and is a function of position along the optical path z. The characteristics of the temporal variations of the index of refraction are related to both C(n)2(z) and to the transverse wind velocity V(z). Current optical techniques for remotely sensing C (n)2(z) and V(z) rely primarily on the spatial or temporal cross-corre lation properties of the intensity of the optical field. In the remote -sensing technique proposed here, we exploit the correlation propertie s of the wave-front slope measured from two point sources to obtain pr ofiles of C(n)2(z) and V(z). The two sources are arranged to give cros sed optical paths. The geometry of the crossed paths and the character istics of the wave-front slope sensor determine the achievable resolut ion. The signal-to-noise ratio calculations indicate the need for mult iple measurements to obtain useful estimates of the desired quantities .