How to measure rainfall

Question 1: How to measure the depth of water layer accumulated on the water surface without evaporation, infiltration and loss, which is called rainfall (in millimeters), which can directly indicate the magnitude of rainfall. At present, the commonly used instruments for measuring rainfall are rainfall cylinder and measuring cup. The diameter of the rain tube is generally 20 cm, and it is equipped with a funnel and a bottle. The measuring cup has a diameter of 4 cm and is used together with the rainfall tube. When measuring, pour the rainwater in the rainfall cylinder into the measuring cup, and you can know the rainfall of the day according to the scale on the cup. ? According to the regulations of China Meteorological Bureau, the rainfall within 24 hours is called daily rainfall, and 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. Due to China's vast territory, a few areas have other provisions according to the specific conditions of this province. For example, in rainy Guangdong, if the daily rainfall exceeds 80 mm, it is called rainstorm; In Yan 'an, Shaanxi Province, where there is little rain, is it called rainstorm when the daily rainfall reaches more than 30 mm? Don't worry if you don't have a rain cone at hand. You can make one by yourself with some commonly used utensils, and the effect is quite good. Take a disposable plastic or paper bowl with a diameter of 20 cm (you can choose a convenient paper bowl with a suitable size), cut a small hole slightly larger than corn kernels at the bottom, and then put the bowl on a pot without a cover. There is a glass bottle in the jar, and the bottle mouth is connected with the small hole in the bottom of the bowl. The simple rain tube is ready. After the simple rainfall pipe is completed, it can be placed 70 cm above the ground (the distance between the nozzle and the ground) to receive rainwater. After the rain stops, weigh the water in the bottle with a scale. 30 grams of water is equivalent to 1 mm of rainfall.

Question 2: How does the average rainfall measure the precipitation in a certain period of time? The depth of rainwater collected during this period without any infiltration, evaporation and loss is called precipitation during this period, and the unit is millimeter (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. ......& gt& gt

Question 3: How to measure precipitation with rain gauge How to use rain gauge;

In a certain period of time, the depth of water layer accumulated by liquid or solid (after melting) precipitation falling from the cloud to the horizontal ground without infiltration, evaporation and loss is called precipitation during this period, and the unit is millimeter. In meteorology, precipitation intensity is usually divided by precipitation in a certain period of time. The most commonly used rainfall classification method is to classify rainfall according to the amount of precipitation. According to the precipitation standard stipulated by the national meteorological department, rainfall can be divided into light rain, moderate rain, heavy rain, heavy rain, heavy rain and torrential rain. Similarly, the size of snow is also classified according to precipitation. Snow can be divided into light snow, medium snow and heavy snow.

The rain gauge is an instrument used to measure the accumulated precipitation over a period of time. The shell is a metal cylinder divided into upper and lower parts. The upper section is a water funnel with a diameter of 20 cm. In order to prevent the rain from splashing and keep the area and shape of the bottle mouth, the cylinder mouth is made of hard copper into a blade shape with straight inside and oblique outside. Put a water storage bottle in the lower bucket to collect rainwater. When measuring, pour rainwater into a special rainfall cup and read the millimeters of precipitation. In the snow season, take out the water storage bottle and replace it with one without a funnel. Snowflakes can be collected directly in the rain tube and watched after the snow melts. You can also weigh the snow and convert it into millimeters according to the area of the mouth.

Don't worry if you don't have a rain cone at hand. You can make one by yourself with some commonly used utensils, and the effect is quite good. Take a disposable plastic or paper bowl with a diameter of 20 cm (you can choose a convenient paper bowl with a suitable size), cut a small hole slightly larger than corn kernels at the bottom, and then put the bowl on a pot without a cover. There is a glass bottle in the jar, and the bottle mouth is connected with the small hole in the bottom of the bowl. The simple rain tube is ready. After the simple rainfall pipe is completed, it can be placed 70 cm above the ground (the distance between the nozzle and the ground) to receive rainwater. After the rain stops, weigh the water in the bottle with a scale. 30 grams of water is equivalent to 1 mm of rainfall.

Question 4: What can be used to measure rainfall? When measuring the measured data, there are two main units: rain gauge and rain gauge.

raingauge

An instrument for measuring the total amount of liquid and solid precipitation in a certain period of time. Generally a cylinder with a diameter of 20 cm. In order to keep the shape and area of the mouth, the cylinder must be hard. In order to prevent rainwater from splashing in, the barrel mouth is in the shape of a blade with straight inside and inclined outside. There are two kinds of rain gauges: those with funnels and those without funnels. A water storage bottle is arranged in the cylinder. In the snow season, the water storage bottle is taken out and replaced with a funnel-free mouth, so that snowflakes can be directly stored at the bottom of the rainfall tube.

Rain gauge is an automatic recording instrument that can continuously measure and record liquid precipitation. There are two kinds in common use: siphon type and tipping bucket type.

① Siphon rain gauge. When rainwater enters the measuring cylinder through the funnel, the float in the measuring cylinder rises with the water level. When the cylinder is full of rainfall of 10 (or 20) mm, siphonage occurs in a short time, and the water in the cylinder is discharged at one time, so that the float records from scratch again. The self-recording pen tip on the buoy can draw the process of rainfall accumulation with time on the clock barrel.

② Dump bucket rain gauge. Its measuring instrument is two triangular tipping buckets, only one of which faces the funnel mouth at a time. When the tipping bucket is filled with 0.2 mm precipitation, it will be overturned due to the outward shift of the center of gravity, and the water will be dumped. At the same time, the second tipping bucket is moved below the funnel mouth, and precipitation data can be obtained from the records of the number and time of tipping bucket alternation. The tipping bucket rain gauge can be used in automatic weather stations.

Use millimeter units when measuring data.

The rainfall between10 and 24.9 mm is moderate rain.

When the rainfall is between 25 and 49.9 mm, it is a rainstorm.

Heavy rain will occur when the rainfall is between 50 and 99.9 mm.

Heavy rain occurs when the rainfall is between 100 and 249.9 mm.

Heavy rain occurs when the rainfall is greater than or equal to 250 mm.

Question 5: How to measure rainfall? Use the rain gauge!