Aircraft Hazard Assessment from a Clear-Air Radar and Meteorological Tower Study of Gravity Wave Events

摘要

An exceptionally well-defined gravity wave event, recorded by radar and on the 300 meter meteorologicaltower near Erie, Colorado, is analyzed in this report. Special attention is given the kinematic structure within the wave to assess possible hazards to aircraft. It is found that changes of about 5 ms to the minus 1 in vertical velocity would be encountered by an aircraft in a time period of 6.5 s. A similar change in air speed would be encountered 90 degrees out of phase with the up-downdraft. The maximum effect in this event was at a height of 100-150 m above the ground. Events of this kind would often occur in fair weather under thermally stable atmospheric conditions, and would not, therefore, be predicted from the usual reasoning about near-ground hazards to aircraft.