What is the concept of this rainfall 100mm?

100 mm rainfall can be called rainstorm. The accumulated depth of water layer without evaporation, infiltration and loss at any position in the rainfall area is100 mm.

Generally speaking, light rain, moderate rain, heavy rain and rainstorm are generally measured by daily rainfall. Among them, light rain means that the daily rainfall is below 10 mm; Daily rainfall in moderate rain 10~24.9 mm; The rainstorm rainfall is 25~49.9 mm; The rainstorm rainfall is 50~99.9 mm; The rainstorm rainfall is 100~250 mm; The rainstorm rainfall is above 250 mm.

Rainfall is the depth of the water layer that falls on the ground at a certain point or a certain unit area in a certain period of time, calculated in millimeters. According to the provisions of the Flood Control Manual of the National Defense Office, any 24-hour cumulative rainfall exceeding 50 mm is designated as a rainstorm.

Extended data:

Rainfall is generally measured by rainfall pipes, so it may contain a small amount of dew, frost and pine branches. Meteorology, there is always precipitation in years, months, days, 12 hours, 6 hours or even 1 hour, and all the rain and snow falling within 6 hours melt into water, which is called 6-hour precipitation; All the rain and snow falling within 24 hours melt into water, which is called 24-hour precipitation; A ten-day rain and snow melt into water, which is called ten-day precipitation. ...

In a year, all the falling rain and snow melt into water, which is called "annual precipitation". Liquid precipitation is called rainfall, and sometimes the two are synonymous. The precipitation per unit time is called precipitation intensity, usually in millimeters per hour or millimeters per minute. The rainfall per unit time is called rainfall intensity.

The average annual rainfall of a place for many years is called the "average annual rainfall" of this place. For example, the average annual rainfall in Beijing is 532.0mm, and that in Shanghai is1166.1mm. ..

Precipitation refers to a weather phenomenon in which liquid water or solid water falls to the ground. Accurate measurement of precipitation is of great significance for weather forecast, climate analysis, monitoring and early warning of natural disasters such as floods, landslides and mudslides.

References:

Baidu encyclopedia-rainfall