Is the amount of rain determined by the amount of rainfall?

The weather forecast says there will be light rain but heavy rain; Sometimes, the weather forecast says it is moderate rain, but it rains all day in Mao Mao. For this reason, we are often confused.

It turns out that the size of rain is determined by the amount of rainfall. Rainfall refers to the depth of rain that falls on the horizontal ground in a certain period of time. Of course, there should be no evaporation, infiltration and loss of rain at this time.

According to the regulations of the meteorological department, the rainfall within 24 hours is less than 10 mm, or the rainfall within 12 hours is less than 5 mm, which is called light rain; It is called moderate rain when the 24-hour rainfall reaches 10 ~ 25mm or 12 hour rainfall reaches 5 ~ 15mm. Rainstorm is called when the rainfall reaches 25 ~ 50 mm in 24 hours or 12 hours and 15 ~ 30 mm. Heavy rain occurs when the rainfall reaches 50 ~ 100 mm in 24 hours, or when the rainfall exceeds 30 mm in 12 hours.

[I still want to know]

Clouds in the sky only account for less than 2/ 10 of the whole sky, which is sunny; Clouds exceeding 810 in the sky are cloudy; The cloud between them is cloudy.

The largest raindrop has a diameter of 4 mm, but it rains less than 0.5 mm in Mao Mao.