THE AUSTRALIAN DESERT

THE DESERT ENVIRONMENT

The Outback. The Dead Heart. The Desert. These names make you think of images of heat, vast tracts of sand, a featureless wasteland where little grows and nothing lives. Many people think a desert is a desolate and lonely place. The desert by moonlight, animals that are nowhere to be seen during the day are everywhere. As dawn comes, the star-filled sky slowly changes from black to stripes of blue, green, orange until the rising sun breaks over the horizon and lights up dewdrops on flowers and huge spider webs that stretch between the desert trees, despite the lack of rain.

HOW THE DESERTS WERE FORMED

Australia was not always south of the Equator. As Australia formed, it appears to have travelled to the north and is now moving steadily northwards. At present, desert covers a large part of Australia, The Great Sandy Desert, The Gibson Desert and the Great Victoria Desert combine to fill more than half of Western Australia. To the east lies Tanami Desert, The Simpson Desert, and The Sturt's Stony Desert.

Two belts of desert run around the earth. One is north of the equator and one south. The desert belts were formed by hot air rising at the equator which carries moisture upwards. As this air reaches the cooler upper layers of the atmosphere the moisture condenses into drops producing the high rainfall that is typical of tropical regions. This air is then cold an dry. It begins flowing to both north and south from the equator, falling downwards to the Earth about one-third of the way to both the north an south poles. These are the desert regions belts. The air then turns and flows to the equator again. The desert areas of Australia were once coverd by sheets of polar ice and, well before that, by great areas of shallow seas. As our continent edges slowly northwards, its desert regions will have time to reach the equator and once again become tropical regions.

Patrick Thaiday, Herberton Qld Australia

References

Rob Morrison The Australian Desert Jacaranda Press 1992 pp4, 5

Picture from The Down Under Collection Delux, New Horizons, Armidale, Australia, 1995.