All-Sky Gravity Wave Imager
 The USU
All-Sky Imager is a very sensitive instrument designed specifically to detect
faint visible and near infrared emission signatures in the night sky termed
"airglow". There are several naturally occurring airglow emissions which originate
in relatively thin layers (8-10 km half-width), in the Mesosphere and Lower
Thermosphere (MLT) region (80-100 km). As atmospheric waves generated by strong,
often weather related, disturbances in the troposphere propagate up through
the atmosphere they perturb the airglow layers causing density and temperature
variations which are then detected by the imager as periodic line-of-sight variations
in the airglow emission intensity. This simple technique offers a unique capability
to investigate three-dimensional nature of the gravity waves as they propagate
and/or break in the MLT region.
Our goal is to investigate the seasonal occurrence and properties of small-scale
gravity waves (observed periods < 1 hr) over the Rocky Mountains which are thought
to be prolific generators of such waves due to strong orographic wind forcing.
The All-Sky imager forms part of a "chain" of three imagers currently operated
in the Rockies to investigate gravity wave dynamics as part of a collaborative
NSF CEDAR program with the NASA TIMED satellite mission.
In addition to the MLT measurements, the All-Sky Imager
is also configured to study F-region perturbations in the 630 nm emission (altitude
250 km). Measurements are made in sequence with the MLT images to investigate
the occurrence and properties of medium-scale Traveling Ionospheric Disturbances
(TID), Sub-Auroral (SAR) arcs, and high altitude auroral precipitation during
enhanced magnetic disturbances.
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Camera Images