What is the basis for the amount of rainfall? How many millimeters of rainfall is considered heavy r

The depth of the water layer that falls from the sky to the ground, and the depth of the water layer that accumulates on the surface of the water without evaporation, infiltration, or loss, is called rainfall (in millimeters), which can visually indicate the amount of rainfall. At present, the commonly used instruments for measuring rainfall include rain measuring cylinders and measuring cups. The rain gauge is generally 20 cm in diameter and contains a funnel and a bottle.

The measuring cup has a diameter of 4 cm, and it is used with a rain gauge. When measuring, pour rainwater from the rain scale into a measuring cup, and you can know the amount of rain for the day according to the scale on the cup.

The China Meteorological Administration stipulates that the rainfall within 24 hours is called the daily rainfall, and the daily rainfall is less than 10 mm is called light rain, millimeters are moderate rain, millimeters are heavy rain, heavy rain is millimeters, heavy rainfall is millimeters, and more than millimeters are called extremely heavy rainfall. Due to the vast territory of our country, a small number of areas have other provisions according to the specific conditions of the province.

For example, in the rainy Guangdong, the daily rainfall of more than 80 mm is called heavy rainfall; In the Yan'an area of Shaanxi Province, where there is little rain, the daily rainfall of more than 30 mm is called heavy rainfall.

Please note that don't consider its actual meaning, because rainfall is the same as temperature, it is only a measurement method to calibrate it, for example, we can set the freezing point of water to 0 degrees Celsius, of course, we can also set the average body temperature of people to 0 Richs, these are all relative, just a ruler used to calibrate rainfall and temperature, as for the zero line of the ruler, you can go anywhere.

It is read out according to the rain gauge data!

It's how deep the rain falls into the rain gauge!

Every weather station has a tool to measure rainfall.

Rainfall of more than 50 mm in 24 hours is considered heavy rain.

According to China's meteorological regulations, rain with a rainfall of 50 mm or more in 24 hours is called "heavy rain". According to the intensity of precipitation, it is divided into three levels, that is, the 24-hour precipitation is 50 mm, which is called "heavy rain"; Below 100 250 mm is considered a "heavy rain"; Temperatures above 250 mm are called "heavy rainfall".

China belongs to the monsoon climate, is a country with many heavy rains, except for individual provinces and regions in the northwest, almost all have heavy rainfall, from late spring to midsummer, the cold air in the north and fight and retreat. Warm and cold air frequently meet, creating a torrential rain.

The location of the major rain bands on the continent also shifts from south to north with the season. South China (Guangzhou, Fujian and Taiwan) is the region with the most heavy rainfall in China. The rainy season is from April to September.

From the second half of June to the first half of July, it is usually the rainy season in the Yangtze River basin. In late July, the rain band moved to the north of the Yellow River, and after September, the winter monsoon weakened and the rain band retreated southward. Due to the influence of the summer monsoon, the distribution of rainstorm days and rainfall in China decreases from southeast to northwest inland, and there are more mountains than plains.

In addition, the southeastern coastal islands and coastal areas have the most heavy rain days, and the more northwest they go, the more they decrease. In the Northwest Highlands, there is an average of less than a day of heavy rain per year. The slopes to the southeast or east, such as Taihang Mountain, Dabie Mountain, Nanling Mountain, and Wuyi Mountain, are the centers of heavy rain days in these areas.

Rainfall is the depth of the water layer that falls on a certain point on the ground or on a certain unit area in a certain period of time, measured in millimeters.

Generally, a rain gauge is used to measure the precipitation in a certain literal area during a period of Chongxiao spring.

Provisions: The rainfall within 24 hours is called the daily rainfall, where the daily rainfall is less than 10 mm is called light rain, millimeters are moderate rain, millimeters are heavy rain, heavy rain is millimeters, heavy rainfall is millimeters, and more than millimeters are called extraordinarily heavy rainfall.

Rainfall measurement process:

1. The diameter of the rain gauge is 20cm, and it is filled with a funnel and a bottle.

2. The diameter of the measuring cup is 4cm, and it is used in conjunction with the rain measuring cylinder.

When measuring, the rainwater from the rain scale is poured into a measuring cup, and the amount of rainfall for the day can be read according to the scale value on the cup.

Extended Materials. Here are the rainfall levels:

The daily rainfall of less than 10 mm is called light rain, the daily rainfall of millimeters is moderate rain, the daily rainfall of millimeters is heavy rain, the daily rainfall of millimeters is heavy rain, the daily rainfall of millimeters is heavy rain, and the daily rainfall of more than millimeters is called extremely heavy rain.

Rainfall is calculated using a rain meter. 1 mm of precipitation is defined as 1 mm of water depth per unit area. There are two types of instruments for measuring precipitation: rain gauge and rain gauge.

A rain gauge is an instrument used to measure the amount of accumulated precipitation over a period of time. The shell is a metal cylinder divided into two sections, the upper section is a water funnel with a diameter of 20 cm, in order to prevent rainwater splashing, maintain the area and shape of the mouth, the mouth of the cylinder is made of hard copper inside straight and oblique outside. The meteorological department calls both rain and snow precipitation, and the amount of precipitation is called precipitation, and the unit of precipitation is usually millimeters.

1 mm of precipitation is defined as 1 mm of water depth per unit area.