What is the rainfall of the rainstorm?

According to China's meteorological regulations, heavy rainfall with a precipitation of more than 50 mm in 24 hours is called "rainstorm". Due to the different characteristics of precipitation and topography, the standards of rainstorm and flood are different in different places.

Rainstorm is a kind of disastrous weather, which often causes floods and serious soil erosion, leading to major economic losses, such as engineering accidents, dike breaches and crop flooding. Especially for some low-lying and blocked areas, rainwater can't be discharged quickly, which leads to water accumulation in farmland and supersaturation of soil moisture, which will lead to more geological disasters.

The formation process of rainstorm is quite complicated. From the macroscopic physical conditions, sufficient and continuous water vapor, strong and lasting upward movement of airflow and instability of atmospheric structure are the main physical conditions for the occurrence of heavy rain.

The favorable combination of various scales of weather system and underlying surface, especially topography, can produce heavy rain. The main weather systems that cause large-scale rainstorm in China are fronts, cyclones, shear lines, eddies, troughs, typhoons, easterly waves and intertropical convergence zone.

Extended data:

Within 24 hours, the amount of rainfall falling from the air is 50.0 mm and 99.9 mm, ranging from 100.0 mm to 199.9 mm, and it is a torrential rain when it exceeds 200.0 mm.. To produce rainstorm, there must be enough water vapor, strong and lasting upward movement of airflow and instability of atmospheric structure.

The favorable combination of weather system and underlying surface, especially topography, can produce heavy rain. Rainstorms often fall from cumulonimbus clouds. The updraft in the cumulonimbus cloud is very strong, the vertical speed can reach 20 ~ 30m/s, and the maximum speed can reach 60m/s, even higher than the wind speed of typhoon.

In the strong updraft, the water droplets keep increasing, and the water droplets in the cloud drop sharply to the ground until the updraft can't support it.

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