Aperture averaging effects on the two-color correlation of scintillations

The scintillation two-color correlation coefficient was measured using a variable aperture. The correlation, at constant aperture, vs turbulence strength and the aperture averaging effects at constant turbulence strength were obtained. The results show a strong decrease or correlation with increasing turbulence strength and a moderate increase with increasing aperture. These results cannot be accounted for by a constant shape turbulence spectrum. It is shown that a turbulence strength-dependent inner scale can explain most of the results using the Rytov approximation.