Abstract
During 1985–86 a summary and review of gravity wave measurements was made by Reid. In particular a collation of 408 horizontal wavelengths was prepared, which included values from optical and radar methods. Since that time substantial new datasets have emerged from the Medium Frequency radars at Adelaide and Saskatoon, and from the CEDAR lidar at Urbana. These data are combined with the earlier collation to form composite figures. Questions are raised about the selectivity of the sounding systems.