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

An optical technique is described that determines the path-averaged value o f a refractive-index structure parameter at 10.6 mu m by use of a pulsed co herent CO2 Lidar in direct detection and hard-target returns. The Lidar mea surements are compared with measurements taken by a 0.9-mu m scintillometer and temperature probe (with humidity corrections). The experimental result s show good agreement far C-n(2) greater than or equal to 10(-14) m(-2/3). With respect to practical applications the new technique permits C-n(2) lid ar measurements in a neutral meteorological situation to an unstably strati fied convective boundary layer over long ranges (1 km or more). (C) 1999 Op tical Society of America.