Annual variation of airglow heights derived from wind measurements

Three independent techniques for measuring wind in the mesosphere and lower thermosphere region were compared using simultaneous measurements during the period May 1997 to April 1998. The three instruments used, a Fabry‐Perot spectrometer, a medium frequency radar, and a meteor radar, are located on New Zealand's South Island. The results obtained during this investigation show reasonable agreement amongst the three methods, in particular between the Fabry‐Perot and the meteor radar. Correlation analysis of the meteor radar height‐resolved winds and the Fabry‐Perot spectrometer winds provides a valuable method for determining airglow heights. The results from the height determinations show a yearly variation of the OH emission layer, with its lowest height during summer, while the OI emission layer is found to remain at a relatively constant height.