Progress in research on atmospheric turbulence



In ground- and tower-based instrumentation for direct sensing, few, if any, new concepts have appeared, but steady improvements in technique and reliability have been reported [Dyer et al., 1967; Goddard, 1970; Hicks, 1969; Kaimal, l9687semi; Kaimal et al, 1968; Thurteil et al., 19707semi; Wesely et al., 1970], and comparisons have been made between different kinds of instruments [Businger et al., 19677; Miyake et al, 1970a], leading generally to increased knowledge and confidence in the characteristics of each. More rapid advances occurred in aircraft-based instrumentation. In particular the utilization of inertial navigation systems by Axford [1968], by the Air Force Hicat program [Crooks et al., 1968] and by the National Center for Atmospheric Research-Desert Research Institute program [National Center for Atmospheric Research, 1970] is leading to the ability to measure the larger turbulence scales and mesoscales, where much of the important energy generation resides, in levels above the surface boundary layer, Sheih [19717] has effectively utilized hot wire anemometry to measure the microscales of turbulence from an aircraft. Precision radar-tracked balloons of either the constant-level type [Angell et al., 1968], or with a roughened surface to improve stability [DeMandel and Scoggins, 1967[, have been used to reveal details of the mesoscale wind field.