What is a hot desert?
Hot deserts are areas of the Earth’s surface that receive less than 25cm or 10 inches of rainfall yearly. Deserts are part of a broader class of regions called drylands. Dryland areas are under a “moisture deficit,” meaning they can frequently lose more moisture through evaporation than they receive from annual precipitation.
Not all deserts are hot; cold deserts exist as well. The largest hot desert in the world is northern Africa’s Sahara, where daytime temperatures can reach up to 50°C (122°F). Some deserts, such as the Gobi desert in Asia and the polar deserts of the Arctic and Antarctic, are always cold. Other areas of the desert are mountainous. Only around 20% of deserts are covered in sand.
What are the characteristics of hot deserts?
Hot deserts typically contain little or no vegetation. The main characteristics of hot deserts are:
- Aridity – the primary characteristic of a hot desert is its dryness or aridity. Hot deserts have total annual rainfall below 250 centimetres per year. This is caused by the dominance of belts of high atmospheric pressure existing at these latitudes (see global atmospheric circulation). Sinking air prevents the formation of clouds and rain, resulting in arid conditions. It is difficult to predict rainfall; it may only rain once every two or three years.
- Temperature – as the name implies, summer temperatures of hot deserts rise well above 40°C. The daily range in temperatures is very high. During the day, temperatures could reach 50°C, whereas, at night, they can be as low as -2°C.
- Landscapes – deserts are often considered vast areas of dunes, but most deserts are rocky, desolate places with isolated thorny bushes and cacti.
- Vegetation – plant growth is minimal as there is a lack of rainfall. The type of plants typically found in deserts include cacti and thornbushes. Plants tend to be short; however, some cacti can grow tall. Most plants have a short life cycle and only appear when it rains.
- Soils – soils are usually very shallow. They typically have a rough gravelly texture. The soil isn’t very fertile because there is little vegetation to provide litter and humus. Therefore there is little or no little layer. Due to a lack of organic material and rainfall desert, the soil is often dry and infertile.
- Animals – to survive the desert environment, animals must adapt. Mammals are often small and nocturnal; they only come out at night when temperatures are low. They sleep below the ground during the day to avoid the heat. Most birds only return to the desert when the climate is favourable.
The reasons for these characteristics are mainly because of the location of deserts.