How is the desert formed? Why is it so hot during the day and so cold at night?

Excluding human activities, deserts are mainly formed by four factors:

I. Atmospheric high pressure area

Sunlight is perpendicular to the equator, which means that the solar radiation received there is very strong. Due to the abundant supply of seawater near the equator, the air here not only carries heat, but also carries more water vapor.

Once the warm and humid air rises, it begins to cool down. With the appearance of water vapor condensation and precipitation, it began to rain in the tropics. This is one of the reasons for the existence of tropical rain forests in the equatorial region.

After the equator releases most of the water, the air moves to the north and south of the equator. The air reaching tropical regions of the Tropic of Cancer and Tropic of Capricorn lost most of its moisture and became dry. Drought and water shortage led to the desert in the middle latitude.

Second, the continental climate zone.

Continental climate refers to the distance between inland and ocean and its influence on climate. When water evaporates from a body of water, it will settle on land.

The area near the water body absorbs most of the water. When the air flows inland, it has lost most of its moisture.

This leads to the formation of deserts in inland areas, because the air flow loses moisture and becomes dry after a long journey. This phenomenon is very common in Asian deserts, just like the Gobi Desert in China.

Three. Coastal desert area

When air reaches an area and is cooled and heated, it also forms a desert. As we mentioned earlier, cold air carries less water than warm air.

Coastal deserts are usually located on the west coast of the mainland near the Tropic of Cancer and Tropic of Capricorn. With the flow of cold air, the temperature and humidity drop to form mist, but it won't rain. The Atacama Desert in South America belongs to this category. This is the driest desert in the world.

Fourth, the rain shadow area

A mountain has a leeward side and a windward side. The leeward side is far away from the prevailing wind. The windward side faces the prevailing wind. Deserts are formed on the leeward side of mountains.

When moisture-rich air reaches the mountains, as the mountains rise, the air rises, cools and stays on the windward side. On the mountain, when the air reaches the leeward side, it drops and starts to heat up.

Warm air is difficult to form clouds. Due to the lack of rain, the desert formed. Death Valley in America is a desert caused by rain shadow areas.

Why is the desert so hot during the day and so cold at night?

When substances come into contact with a heat source, their temperature will rise, but different types of substances have different reactions to heat.

We all know that there is less water and more sand in the desert, and sand and stones heat faster than water. The heat required to raise the temperature of a substance by 65438 0 degrees Celsius is called specific heat capacity. The specific heat capacity of water is 4. 19, and that of sand and gravel is 0.8.

So, you can imagine how fast the desert is warming compared with the area with a large area of water nearby. No matter how hot it is during the day, the temperature in the desert usually drops sharply at night, and the hot spot at noon becomes very cold at night. This is because sand and rocks not only heat up quickly, but also dissipate heat quickly.

In other words, when the sun shines, the desert is hot, but once the sun goes down, this area will soon lose heat and become cold at night.