The atmospheric layers from 60 to 200 km above the Earth's surface can be sounded only by expensive rocket-launched experiments, problematical indirect methods, or satellites in rapid orbital decay. Measurements of large-scale phenomena are masked by large amplitude perturbations, both aperiodic and tidal. Still the needs of the rapidly increasing traffic of aerospace vehicles through this region must be served. There is a growing requirement for meteorologists to apply their special skills to the analysis of the costly data now accumulating in substantial amounts from the mesosphere and lower thermosphere.
1The text of this article includes various statements and was amended in accordance with suggestions made by many specialists in aerospace science, including Bernard Charles, Arnold Court, Roderick S. Quiroz, Norman Sissenwine, and William W. Vaughan. One result of their consideration of this text was the decision to bring together many prominent aerospace scientists at Miami Beach, May 31–June 2, 1967. (See meeting program in the Bulletin, 48, pg. 210.)