Abbie Thomas
Posts: 1
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Morning Glory Clouds
I would like information about how research on the Morning Glory cloud phenomenom seen in the Gulf of Carpentaria in Australia has been applied to infrasound detection of nuclear tests. This is Doug Christie's area.
With many thanks,
Abbie Thomas
ABC Science Unit, Sydney Australia
07-21-2003 9:06 PM
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Rob Newman
Posts: 2
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Background on Morning Glory clouds
Abbie,
Although I am not involved with this research I thought it would be appropriate to give some background on Morning Glory clouds to visitors of Inframatics.org. The Morning Glory cloud is best known from the Gulf of Carpentaria, northern Australia, where it is observed around dawn during the spring months. The name is derived from the impressive appearance of these long, horizontal clouds (see images below). According to Christie & White, 1995, a Morning Glory is a cloud formed by a solitary wave in the lower atmosphere, which are thought to develop in the presence of a temperature inversion due to atmospheric disturbances such as thunderstorms or the collision of opposing ocean breeze fronts. A temperature inversion is when a layer of colder air close to the ground is overlain with a warmer layer, creating a cover. This cover is highly stable and allows the solitary wave to migrate without being damped, thus enabling the cloud to travel long distances.
Morning Glories appear as one or more roll cloud formations extending from horizon to horizon, sometimes more than 1000 km in length. The base of roll clouds can be 150 to 300 m above the ground or sea surface, and the cloud itself may have a depth of 600 to 1300 m. Morning Glory clouds seldom produce measurable precipitation, but are almost always accompanied by short-lived, often intense, surface wind squall. They are reported to travel at speeds of about 40 km/hr, occasionally over 60 km/hr.
For more information and great images visit the Sable Island Green Horse Society.
Reference: Christie, D. & White, R., 1995. The Morning Glory of the Gulf of Carpentaria. AOPA (Aircraft Owners and Pilots Association of Australia).
Leading edge
Trailing edge
View of the Morning Glory, looking towards the north, before and after it passed overhead. The front of the cloud was very smooth, the back was somewhat turbulent. The cloud was followed by a single line of scattered irregular cumulus.
© June 13 2003 Sable Island Green Horse Society, Sable Island
07-22-03 11:06 AM
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