How clouds form

The principle of cloud formation:

Water on the ground absorbs heat and turns into water vapor, which rises to the upper level of the vapor layer in the sky. Because the temperature of the upper layer of the steam layer is low, the volume of water vapor shrinks and the specific gravity increases, causing the steam to fall.

Because the temperature below the vapor layer is high, it absorbs heat during the descent, rises again and encounters cold, and then descends. Repeatedly, the gas volume gradually shrinks, and finally concentrates at the bottom of the vapor layer. A low-temperature area forms at the bottom, and water vapor concentrates toward the low-temperature area, forming clouds. Extended information

Look at the clouds to know the weather

1. "There are clouds in the sky and rain on the ground":

Cirrus clouds refer to cirrus clouds. Behind the clouds, there are often fronts (especially warm fronts), low pressure or low pressure troughs moving in, which herald the coming of rain;

2. "Fort clouds, drenched with rain":

Fort clouds refer to fortress-shaped altocumulus clouds or fortress-shaped stratocumulus clouds. They often appear in front of low-pressure troughs, indicating unstable air. Thunderstorms usually occur every 8-10 hours.

3. "Clouds cross clouds, rain pours":

Clouds cross clouds means that the upper and lower clouds move in different directions, that is to say, the wind direction at the height of the clouds is inconsistent, which often occurs on fronts Or near low pressure, so it indicates rain. Sometimes the clouds are in the opposite direction to the ground wind, and there is a saying that "clouds move against the wind, and the sky will change."

4. "River pig crosses the river, heavy rain pours":

Jiang pig refers to the broken rain clouds under nimbus clouds. The appearance of such clouds indicates that there is a lot of water vapor in nimbostratus clouds. Plenty, heavy rain is coming. Sometimes broken rain clouds are blown by strong winds to cloudless places. At night, you can see clouds like river pigs floating across the "Milky Way", which is also a precursor to rain.

5. "Cotton cloud, rain is coming soon":

Cotton cloud refers to flocculent altocumulus clouds. The appearance of such clouds indicates that the middle atmosphere is very unstable. If there is sufficient water vapor in the air and there is With upward movement, cumulonimbus clouds will form and thunderstorms will come.

6. "The sky is covered with gray cloth, and the rain is continuous.":

Gray cloth clouds refer to nimbostratus clouds. Most of them are formed by the lowering and thickening of altostratus clouds. They have a large range and It is very thick, with sufficient water vapor in the clouds, often producing continuous precipitation.

Reference: Baidu Encyclopedia-Cloud