What are the characteristics of clouds?

1, the thickness of various clouds varies greatly.

2. colorful

3, the shape changes endlessly

4. There are many kinds

It is closely related to the weather.

Cloud is a visible polymer floating in the air, which is condensed by small water droplets or small ice crystals liquefied by water vapor in the atmosphere when it is cold. Clouds are the tangible result of the huge water cycle on the earth.

The sun shines on the surface of the earth, and water evaporates to form water vapor. Once the water vapor is supersaturated, water molecules will gather around the dust (condensation nucleus) in the air, and the generated water droplets or ice crystals will scatter sunlight in all directions, thus creating the appearance of clouds. Moreover, clouds can form various shapes, and they are divided into many kinds because of their different heights and shapes in the sky.

Extended data:

1, influence

Clouds absorb heat from the ground and reflect it back, which helps to keep the earth warm. However, clouds also reflect sunlight directly back into space, which has a cooling effect. Which effect is dominant depends on the shape and location of the cloud. In the atmosphere more than ten kilometers from the ground, the closer to the ground, the higher the temperature and the richer the air; The higher the altitude, the lower the temperature and the thinner the air.

On the other hand, the water surface of rivers, lakes and seas, as well as the moisture of soil, animals and plants, evaporates into the air and becomes water vapor. After water vapor enters the atmosphere, it turns into clouds to cause rainfall, or condenses into frost dew, and then returns to the ground, permeates the soil or flows into rivers, lakes and seas. Later it will evaporate (vaporize) and then condense (condense) and drop. It goes on and on.

Water vapor enters the lower atmosphere from the evaporation surface, which has a high temperature and a lot of water vapor. If the hot and humid air is lifted, the temperature will gradually decrease, and when it reaches a certain height, the water vapor in the air will reach saturation. If the air continues to be lifted, there will be excess water vapor. If the temperature there is higher than 0℃,

Excess water vapor is liquefied into small water droplets; If the temperature is lower than 0℃, excess water vapor condenses into small ice crystals. When these small water droplets and small ice crystals gradually increase to a level that can be recognized by human eyes, what we call clouds are formed. Note: When the air pressure decreases, the freezing point of water will increase and be higher than 0℃.

2. Know the weather from the clouds

"There are hook clouds in the sky and rain in the ground": Hook clouds refer to cirrus clouds with hooks. Behind this cloud, there are often fronts (especially warm fronts), low pressure or low pressure troughs moving, which indicates that rain is coming;

"Battery cloud, rain": Battery cloud refers to fort-shaped high cumulus cloud or fort-shaped stratocumulus cloud, which appears in front of the trough with low pressure, indicating that the air is unstable, and thunderstorms usually come every 8- 10 hours.

"Clouds pass through clouds, and it rains": Clouds pass through clouds, which means that the moving directions of the upper and lower clouds are inconsistent, that is to say, the height and wind direction of clouds are inconsistent, which often occurs near the front or low pressure, so it indicates rain, and sometimes the wind direction of clouds is opposite to the ground, so there is a saying that "the sky changes when the clouds go against the wind".

"The river pig crosses the river with heavy rain": The river pig refers to the broken rain clouds under nimbostratus. The appearance of this cloud indicates that there is enough water vapor in nimbostratus, and a rainstorm is coming. Sometimes broken rain clouds are blown to sunny places by strong winds, and it is also a precursor to rain to see river pig-like clouds floating across the "Milky Way" at night.

"Cotton cloud, rain is coming": Cotton cloud refers to flocculent cumulus clouds. The appearance of this cloud shows that the middle atmosphere is very unstable. If there is enough water vapor in the air and there is upward movement, cumulonimbus clouds will form and thunderstorms will come.

"Gray cloth hangs over the sky, and the rain will continue": Gray cloth cloud refers to nimbostratus, which is mostly formed by the reduction and thickening of high-level clouds. The range is very large and thick, and the water vapor in the cloud is sufficient, which often produces continuous precipitation.

Baidu Encyclopedia-Cloud