Australia is a magical country. After all, its country accounts for the majority of an independent continent. Therefore, it can be said that it is the largest island in the world. At the same time, it is also the smallest continent in the world. According to the data, it has a total area of 7.69 million square kilometers. Surrounded by the sea, Australia should be a country with warm and humid climate. However, it is not a country with a warm and humid climate There are only large areas of deserts and grasslands. These deserts are also called dead deserts, accounting for 20% of the total land area of the country. It is said that Australians admire the fact that Chinese people don’t need to be adjacent to deserts. But why on earth is there such a wide range of deserts in Australia?
The desert is not formed by blowing
① Desert at 30 degrees north and south latitude
The deserts of Australia are very strange. It’s easy to understand the deserts of the United States or China. After all, these deserts are inland and far away from the ocean, so there is less precipitation. At the same time, the high mountains also block the ocean’s further transportation of water vapor. In addition, the vast land is sparsely populated, the altitude is high, there is no shelter, the vegetation is barren, and the evaporation is huge, The river is seriously cut off and the riverbed is dried up. As a result, over a long period of time, the Taklimakan desert has gradually become a desert under the influence of wind erosion. In China, the Taklimakan desert is formed in this way. Although the latitude is about 30 degrees, Australia is different from the United States and China. These causes are actually the pressure belt.
② The Australian desert forms a pressure belt
As we all know, Australia is adjacent to the equator. If an area is near the equator, it will receive more sunlight. High temperature is natural. At the same time, the air will expand when it is heated, expand and contract when it is heated, and the hot air will move upward, resulting in the subtropical high. On the contrary, the polar area will receive less sunlight, lower temperature, and the density of cold air will sink. Therefore, the high pressure belt is formed Yes.
The earth itself has rotation. It deflects northward in the northern hemisphere and southward in the southern hemisphere. There is a flow of pressure belt on the surface of the earth. Therefore, the environment on the earth will be very different, even at the same latitude or longitude. Therefore, the formation of sand desert in Australia is related to the local pressure belt.
Geographically, Australia is located at 30 degrees south latitude. This area is controlled by the subtropical high pressure belt, where the prevailing downdraft and westerly wind are mostly clear and cloudless weather with high temperature.
For example, summer in the northern hemisphere is often controlled by the subtropical high. Australia is also controlled by the same pressure belt, so it has less precipitation, higher temperature and higher evaporation throughout the year. Even if the ocean carries water vapor, it can’t hold high temperature. As a result, huge deserts gradually formed.
This is also the cause of the Sahara desert and the Peruvian desert. Although these areas are close to the ocean and there are ocean currents, they are all about 30 degrees north and south latitude, which is very easy to form a tropical desert climate.
In addition, the North-South span is narrow, so the desert area is proportional to the area of Australia.
Moreover, the continental margin is relatively complete, and there is no broken coastline, so the water vapor can not be transported inland. Meanwhile, the central and western regions are always flat. Without the uplift airflow, the cold air and hot air can not meet, and the rainfall is impossible. Therefore, the desert area of Australia is very large. At the same time, there are many deserts on the gold coast, that is, the west coast .
So why doesn’t such a region exist in China?
30 degrees north latitude also passes through China, but there is only Taklimakan Desert in China. We have just mentioned the reasons for the formation of Taklimakan Desert. Further analysis shows that our continent is Eurasia, which is also the largest continent in the world. At the same time, it is far away from the ocean, with less rainfall. Moreover, due to the difference of specific heat capacity, the temperature of Taklimakan Desert increases rapidly in summer, which leads to high temperature In this kind of pressure difference, the ocean high pressure will move towards the continental low pressure in summer, so the monsoon circulation will basically form in this area, and in summer, the ocean high pressure will move towards the continental low pressure. Most of China is controlled by monsoon. And because China’s coastline is relatively long and narrow, carrying a lot of water vapor, so the rain is hot at the same time.
The so-called Dead desert in Australia is actually related to the topography, wind belt and ocean current.