What is the rainfall of one millimeter?

Rainfall is divided into six grades, which are light rain, moderate rain, heavy rain, heavy rain, heavy rain and heavy rain.

1, light rain: 1d (or 24h) rainfall is less than 10mm.

2. Moderate rain: 1d (or 24h) rainfall 10-25mm.

3. Heavy rain: 1d (or 24h) with rainfall of 25-50mm.

4. Rainstorm: 1d (or 24h) rainfall is 50- 100mm.

5. Rainstorm: 1d (or 24h) rainfall 100-250mm.

6. Extraordinary rainstorm: 1d (or 24h) rainfall is more than 250mm.

According to different physical characteristics, precipitation can be divided into liquid precipitation and solid precipitation. Liquid precipitation includes rain, rainstorm, thunderstorm, freezing rain and showers in Mao Mao. Solid precipitation includes snow, hail and graupel. And liquid-solid mixed precipitation such as sleet.

According to the precipitation intensity, it can be divided into light rain, moderate rain, heavy rain, heavy rain, heavy rain, heavy rain, light snow, medium snow, heavy snow, heavy snow, heavy snow and heavy snow.

Form of rain:

1, positive rain

Frontal rain mainly occurs in nimbostratus system, and nimbostratus system is the thickest in frontal cloud system. It is also a mixed cloud formed by cold and warm air. Its upper part is ice crystals, the lower part is water droplets, and the middle is often filled with ice water, which can quickly cause collisions.

Because of the large thickness of the cloud, the cloud droplets travel a long distance in the process of merging, which is beneficial to the increase of cloud droplets. The bottom of nimbostratus is close to the ground, so raindrops are not easy to evaporate during falling, which is beneficial to the formation of precipitation. The thicker the rain layer, the closer the cloud bottom is to the ground, and the greater the precipitation.

2. Convective rain

This convective precipitation is characterized by small range, large intensity, uneven distribution, short duration and rapid change with time. Convective precipitation is a common extreme weather phenomenon in the middle and lower reaches of the Yangtze River.

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