Uncovering the mystery of Australia's drought: How do climate, geography and ocean currents create a "desert continent"?

Hello everyone, I am the assistant of Australian Encyclopedia. Recently, some friends asked me aboutAustralian DesertNow I will summarize the related issues, hoping to help those who want to know more.

As the driest continent in the world, Australia has about 701 TP3T of land in arid or semi-arid areas, and 3.4 million square kilometers of desert and desertified land. Behind this amazing data lies the subtle mechanism of the interaction between climate, geography and ocean in Earth system science. This article will deeply analyze the formation code of the "desert continent" from five dimensions.

1. Five core factors of the formation of Australian deserts

1. The Geographical Cage of the Continental Shelf

Australia is located between 10° and 39° south latitude, and its main part happens to be in the global arid zone (15° to 35° south latitude). This special location makes it controlled by the subtropical high pressure belt for a long time, forming a continuous downdraft. This airflow will "crush" the clouds during the compression and heating process, resulting in an average annual precipitation of less than 250 mm.

2. The "rain shadow effect" created by the mountains

The Great Dividing Range in the east is like a natural barrier. When the Pacific water vapor carried by the southeast trade winds is blocked and lifted, abundant precipitation (annual average of 2000mm) will form on the east side of the mountain range, while the west side will become a "rain shadow area". The difference in precipitation between Sydney and Adelaide (1215mm vs 528mm) is a vivid portrayal of this effect.

3. The cooling effect of cold snaps

The WA Current is one of the strongest cold currents in the Southern Hemisphere. Its low temperature (5-8℃ lower than seawater at the same latitude) significantly inhibits seawater evaporation. The water content of air in the sea near Perth is only 12 grams per cubic meter, which is only 1/3 of that in tropical waters. This has directly led to the formation of a 2,000-kilometer drought zone along the coast of Western Australia.

4. Ancient traces of continental drift

Geological research shows that the Australian continent has been moving northward since it separated from the South Pole 55 million years ago, and this movement has gradually caused it to move away from the humid westerly belt. Paleoclimate simulations show that for every degree of latitude the continent moves northward, the central arid area expands by 38,000 square kilometers.

5. Modern drivers of human activity

Nearly 200 years of colonial development has caused a 18% drop in vegetation coverage, an increase in surface albedo by 0.15, and a 2.3°C rise in summer surface temperature. Overgrazing (livestock density of 0.7 units per square kilometer) has further exacerbated the degradation of fragile ecosystems in the Midwest.

2. Five key issues related to Australia’s deserts

1. Are Australia’s deserts continuing to expand?

CSIRO satellite monitoring shows that between 2000 and 2020, the desertification front moved southward by an average of 1.2 kilometers per year. The Simpson Desert has expanded by 7.8%, and the vegetation degradation zone in the Nullarbor Plain is encroaching on marginal grasslands at a rate of 3 meters per year.

2. What special value does the desert have to the ecosystem?

The Australian desert breeds a unique biome in the world: the spiny-horned lizard can set a record of 60°C heat resistance on the surface of the sand, and the roots of desert oaks can penetrate 40 meters underground to absorb water. Microbial spores dating back 50,000 years are also preserved here, providing living samples for the study of life evolution.

3. Symbiotic relationship between mineral resources and deserts

The desert strata in the Pilbara region of Western Australia contain one-third of the world's iron ore reserves, with a hematite (Fe₂O₃) content of up to 64%. The unique weathering process of the desert has created a 30-meter-thick iron cap layer, and this geological structure has reduced the cost of mineral mining by 40%.

4. The wisdom of indigenous people in surviving in the desert

The indigenous people use the "slash-and-burn" technique to maintain ecological balance: controlled burning is carried out every 5-7 years, which not only promotes vegetation renewal but also forms a natural firebreak. The "waterhole positioning method" they invented can find water sources 50 kilometers away through the flight paths of birds.

5. Innovative practices in desert control

Australia is implementing the "Solar Corridor" plan to build a photovoltaic matrix with a total capacity of 28GW in desert areas, which is expected to meet Australia's 60% electricity demand by 2050. At the same time, the "artificial fog" technology is used to collect moisture in the air using temperature differences, and the daily water intake can reach 2,000 liters per hectare.

Thank you for your reading. I hope this article can help you understandAustralian DesertFrom geological evolution to modern governance, this seemingly barren land is writing a new symbiotic relationship between man and nature. When we understand the natural laws of desert formation, we can better grasp the balance between ecological restoration and resource development.