1. survey for updating the turbulence parameter values consisted of a search of the Scientific and Technical Arrospacc Abstracts. the International Aerospace Abstracts, and the Meteorological and Gcoastrophysical Abstracts for the period 1970 t o present. Parameter values resulting from this litreture review have been incorporated into thc turbulence siinulntion suhroutine .
2. I hc selected from the Rnyleigh distribution hy equation ( 4 ) . are assumed to be corrolnted ovcr horizontal and vertical separations w i t h scale values (intrgrnl scale) which are relntcd LO the horizontal and vertical scales of the turbulent velocity, through a ratio which was assiiinrd l o vary from 10.0 at the surface to 5.0 a t 20 kin and higher. For example, with a horizontal turhulrrrcc velocity scale of 0.52 km a t the surface, the horizontal signin scale i s assuined to be 5.2 kin Assumptions such as these were required bccnusc no observational data were found to provide direct estimates of the sigma scales. These ratio values (5-10) wrz-e assumed since turbulent vrlority statistics cannot accurately be determined from measurements unless the turbulence is stationary (relatively Constant sigma) over a t lensi 5 1 0 velocity scale values: hence a presumption that the sigma scales relative to the velocity scales are of a t least this magnitude range (with larger ratio values anticipated to occur at lower altitudes).