Data from Grand Junction are summarized in keogram format. Each keogram shows the fluctuations of the airglow layer at about 87 km in geographic coordinates. Fluctuations are determined as the difference between the background corrected images and averages taken over approximately one hour. The surface meteograms provided by Unisys Weather give helpful information about observational conditions.
Images of the airglow were taken by a camera on board of the Space Shuttle looking back into the wake of the flight path. These images show the airglow layer at about 93 km altitude up to the horizon of the local observer. Traveling along its flight path the camera observes new parts of the airglow layer which can be considered stationary compared to the velocity of the shuttle of about 7 km/s.
A sequence of raw images taken by the Shuttle was added according to the distance the shuttle traveled and then the resulting image was projected on the longitude-latitude grid of the Earth's map. Modern image processing techniques like the Fourier transform technique then show the short wavelength (or high frequency) modulations within the airglow.
Similar observation can also be obtained from aircraft looking up the sky and operating all-sky imagers. The image shows gravity modulated airglow recorded from an aircraft flying over the Pacific Ocean.
Last update: January 31, 2002
by Harald U. Frey, nospam_hfrey@ssl.berkeley.edu