Refractive-index structure parameter in the planetary boundary layer: Comparison of measurements taken with a 10.6-μm coherent lidar, a 0.9-μm scintillometer, and in situ sensors

An optical technique is described that determines the path-averaged value of a refractive-index structure parameter at 10.6 μm by use of a pulsed coherent CO₂ lidar in direct detection and hard-target returns. The lidar measurements are compared with measurements taken by a 0.9-mm scintillometer and temperature probe (with humidity corrections). The experimental results show good agreement for Cn² ≤10^Ȓ14 m^𢄢/3. With respect to practical applications the new technique permits Cn² lidar measurements in a neutral meteorological situation to an unstably stratified convective boundary layer over long ranges (1 km or more).