How to measure the rainfall XX mm in a certain place often mentioned in weather forecast, and what are the standards?

The precipitation in a certain period, the depth of rainwater gathered without any infiltration, evaporation or loss during this period, is called the precipitation in this period, and the unit is expressed in millimeters (mm).

PS。 The unit of precipitation is the length unit, and the daily precipitation should be 0.2mm, preferably 0.1mm; ; The total precipitation in a week or a month should be at least accurate to1mm. The measurement of daily precipitation should be fixed at a certain time period, such as 8: 00 am to 2: 00 pm/kloc-0.

Rainfall regulation

[Author: anonymous reposted from: original hits on this site: 189 Update time: May 24, 2005 article entry: Hu]

When we listen to or watch the weather forecast, we often hear terms such as "light rain", "moderate rain" and "moderate to heavy rain", which is the grade of rainfall. Rainfall means that the rainwater falling on the ground is not evaporated, infiltrated and lost, but is determined by the depth of accumulation. The unit of depth stipulated in our country is millimeter. The level of rainfall is divided into light rain, moderate rain, heavy rain, heavy rain, heavy rain and heavy rain according to the rainfall within 24 hours. Light rain: the rainfall is less than10mm, and the raindrops are clear, which is debatable. When they fall on the roof tiles and hard ground, they will not splash, and the rain will be gentle and intermittent; It usually takes two minutes to completely wet the slate and roof tiles, and the puddle is slowly formed. Moderate rain: the rainfall is between ten and twenty-five millimeters, and the rustling rain can be heard. Rain falls like a line, and raindrops are not easy to distinguish. They splashed gently on the holes and hard ground, and puddles soon formed. Heavy rain: the rainfall is between 25 and 50 mm. When it rains heavily, the rain falls like a downpour, dripping on the roof tiles and hard ground, splashing several inches. The rain is like a drum, and the pool is quickly formed. Heavy rain: the rainfall is between 50- 100 mm, and there is water on the road surface. Rainfall between 100 mm and 200 mm is called rainstorm; Rainfall exceeding 200 mm is called rainstorm, and low-lying areas are flooded. Shower: refers to stratum precipitation, with heavy raindrops and drastic changes in intensity. When it rains, it is dark, sometimes it suddenly clears up, revealing sunny days, and sometimes it is accompanied by thunder.

According to the regulations of China Meteorological Bureau, the rainfall within 24 hours is called daily rainfall. Any daily rainfall below10mm is called light rain,10.0 ~ 24.9mm is moderate rain, 25.0 ~ 49.9mm is heavy rain, 50.0 ~ 99.9mm is rainstorm, and100.0 ~ 250.0mm is rainstorm.

Due to the vast territory of China, the precipitation in the east, west and north is quite different. According to the specific situation of this province, a few areas have formulated local standards for rainstorm. For example, in rainy Guangdong province, the daily rainfall exceeding 80 mm is called rainstorm; In Yan 'an, Shaanxi Province, where there is little rain, it is called rainstorm when the daily rainfall reaches more than 30 mm; Xinjiang has a dry climate and little precipitation. Xinjiang Meteorological Bureau specially named rainy days with daily rainfall greater than or equal to 10 mm as "heavy precipitation".

The meteorological department calls it rain and snow precipitation, and precipitation is called precipitation. The unit of precipitation is usually millimeters. 1mm precipitation refers to the water depth per unit area1mm. /kloc-how much of the 0/mm precipitation fell into the fields? As we know, the area per mu is 666.7 square meters. So 1 mm precipitation is equivalent to an increase of 0.667 cubic meters of water per mu. Every cubic meter of water is 1000 kg, so the precipitation of 1 mm is equivalent to watering about 650 kg of water per mu. According to the measurement, the rainfall of 5 mm can make the dry land soak 3 cm to 6 cm. In the weather forecast issued by the meteorological department, we often hear professional terms such as light rain, moderate rain and heavy rain. What's the difference between them? Light rain refers to rain with the precipitation not exceeding10mm within 24 hours, ranging from 5mm to18mm,10mm to 25mm, moderate to heavy rain to18mm to 38mm, and heavy rain to 38mm to 75mm ... If the rainfall exceeds 50mm within 24 hours, it is called rainstorm; If it exceeds 100 mm, it is called a torrential rain; If it exceeds 200 mm, it is called rainstorm. In weather forecast terminology, different expressions have different meanings. For example, "sporadic light rain" means that the precipitation time is very short, and the precipitation does not exceed 0. 1 mm. "Sometimes there is light rain" means that the weather is gloomy and sometimes there is short-term precipitation. "Rainfall" refers to the sudden start and end of summer precipitation, one big and one small, with heavy rainfall. "Thunderstorm" means a shower accompanied by thunder and lightning. "There is rain in some areas" means that precipitation occurs in a small area and its distribution is irregular.