The PI seeks to explain the disagreement between motions inferred from analyzing incoherent scatter and partial reflection radar data, as measured during AIDA '89. Data sources come from the Arecibo UHF incoherent scatter radar and Utah State University imaging doppler interferometry MF radar. The PI will continue investigating: (1) scattering mechanisms involved, (2) whether IDI scattering points are turbulent eddies carried by the mean flow, (3) distribution of scattering points and their line of sight velocities in each 3km altitude range, and (4) whether ISR results are indicators of bulk motion, and whether the advection of temperature discontinuities is also subject to gravity wave influence.***