How is precipitation calculated? Precipitation. Scheme and types of precipitation How is the amount of precipitation measured
The amount of precipitation is of constant interest to those who follow the weather. It would seem that the forecast is 10-15 mm, and on the streets - knee-deep snow or huge puddles. To make it easier for you to navigate the forecasts, we have prepared information on measuring the amount of precipitation.
Meteorologists distinguish between two concepts: the height of the snow cover and the amount of precipitation. What we see on the street after a snowfall is the height of the snow cover, which sometimes reaches 50 cm, although the amount of precipitation can be no more than 20 mm. One millimeter of fallen snow is equal to 1-1.5 cm of snow cover height, depending on the snow structure.
According to meteorological guidance, a millimeter of precipitation is one liter of water per square meter. At all weather stations there are rain gauge buckets, from which, at 9 and 21 hours GMT, precipitation is poured into a special vessel, by which their amount is measured. Solid precipitation - snow, hail - is melted, and then experts measure the resulting water.
Popular meteorology and climatology
1 millimeter of rain is 1 liter per square meter
(units of anomalous rain and anomalous snow)
Weather forecast, weather news: record rainfall, extreme rainfall, snow hell
Snowfall, winter - 10-15 centimeters of snow falls per day. How is snow measured? In two quantities - in the increase in the thickness of the snow cover and in millimeters of water. If 15 centimeters of snow piled up, then this is only 7.5 liters of water (kilograms) per square meter.
Snow thickness (snow height) for mid-latitudes of 1-1.5 meters is not surprising, snow up to 2-4 meters in the mountains is the norm of precipitation for a temperate climate zone.
Snow piled up measured by snow gauges in centimeters and meters, and the water content in the snow - the snow is simply melted and the volume of water obtained from melting is measured.
A snowfall of 10-20 centimeters of snow is not something extreme, 10-20 centimeters fell overnight - this is normal snowfall.
Freshly fallen snow has a density of only about 50 kg / cubic meter, during a snowstorm the density of snow is up to 120-180 kilograms per cubic meter. Well-packed snow has a density of up to 0.5 (tons per cubic meter).
Snow on the roofs is successfully kept with slopes of 60 degrees and the wind blows and slaps it. But it can be an avalanche. So it remains to be seen which roof is better - flat or steep. The snow load on the roof (the snow is rammed by the wind!) may well be 0.5 tons per square meter (1 meter vertically). Therefore, the collapse of the roof under the snow - old roofs or new roofs (on which they saved a lot - materials were replaced), balconies are not uncommon.
Weather news: "up to 10-15 mm of precipitation will fall, more than a quarter of the January norm. The increase in snow cover may be 7-15 cm."
10 millimeters of precipitation is a layer of water if the snow that has fallen is melted. Freshly fallen snow is 20 times looser than water (20 times less dense), therefore, the weather forecast promises 20-30 fluffy snow if there is no wind. Is the increase in snow cover in the weather forecast 2 times less? This is taking into account the fact that the snow is slightly rammed by the wind.
Weather forecast, meteorological news: record downpour, thunderstorm, prolonged extreme precipitation, abnormal rain
Precipitation measurement - rain gauge, precipitation gauge, pluviograph.
Millimeters of precipitation is the amount of water height if it did not flow anywhere. For example, if after a rain the water increased by 1 centimeter, then 10 millimeters of precipitation fell. That is, the rain poured water 10 liters per square meter. This is average heavy rain, nothing extreme.
But when the soil can no longer absorb water or has not yet thawed, and there is nowhere to drain, then wait for flooding in low places.
Precipitation observations, examples of precipitation
Winter precipitation, photo
Location: 10 kilometers from Varna (Bulgaria)
Summer precipitation, photo
Location: city of Burgas on the Black Sea, Bulgaria
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The average annual rainfall is an important part of climate data - those recorded using various methods.
Precipitation (most often includes snow, hail, sleet, and other types of water falling on the ground) is measured in units during certain period time.
In the United States, precipitation is usually presented in inches per 24 hour period. This means that if one inch of rain falls in a 24 hour period and the water does not soak into the ground and flow down after the storm, there would be a layer of one inch of water covering the ground.
For Low Tech rainfall measurements, a container with a flat bottom and straight sides (e.g. a coffee cylinder) is used. While a cylinder can help you determine if a rainfall is one or two inches of rain, it is difficult for them to measure small amounts of precipitation.
Weather watchers use more sophisticated instruments known as rain gauges and tip buckets to measure precipitation more accurately. Rain gauges have wide openings at the top for rainfall. The rain is directed into a narrow tube, one-tenth the diameter of the top of the neck. Because the pipe is thinner than the top of the funnel, the units are farther apart than they would be on a ruler, and accurate one-hundredth (1/100 or 0.01) of an inch measurements are possible. When the rate is less than 0.01 inches of rain, this amount is called the "footprint" of rain.
A bucket fitted with a sensor records precipitation readings on a rotating drum or electronically. It has a funnel like a simple rain gauge, but the funnels lead to two tiny "buckets". The two buckets are balanced and each has 0.01 inch of water. When a bucket is full, its bottom is emptied while the other bucket is filled with rainwater. Each tip of the bucket triggers a device to record an increase of 0.01 inches of rain.
Snowfall is measured in two ways. First, it is a simple measurement of the layer of snow on the ground with a stick marked with units of measure. The second measurement determines the equivalent amount of water per unit of snow. To obtain this coefficient, the snow must be collected and melted into water. Typically, 10 inches of snow produces one inch of water. However, this may apply to loose, fluffy snow, although as little as 2-4 inches of wet, compacted snow can produce an inch of water.
Wind, buildings, trees, terrain and other factors can change the amount of precipitation, and such snowfall is usually measured from obstacles. The thirty-year mean annual rainfall is used to determine the average annual rainfall for a particular location.
Author Yeelina Diona asked a question in Climate, Weather, Time zones
What is precipitation in millimeters? and got the best answer
Answer from Helga[guru]
Precipitation is measured by the thickness of the layer of fallen water in millimeters.
Precipitation is measured by rain gauges, precipitation gauges, pluviographs at meteorological stations, and for large areas- with the help of radar.
In meteorological observations, precipitation is characterized by the duration and intensity of precipitation, as well as by the amount expressed in the thickness of the layer of fallen water.
The amount of precipitation is expressed in millimeters of the water layer that would form from precipitation if it did not evaporate, seep into the soil or run off.
Numerically, the amount of precipitation in millimeters is equal to the number of kilograms of water spilled onto a site of 1 sq. km. meter, i.e. 1 mm = 1 kg / 1 m2.
___________________________
But how to quantify what 1 mm of precipitation is?
Not many can correctly explain how much it is.
For example, how to imagine 1000 mm of rainfall on an area of 1 hectare.
Knowing that 1 hectare = 10,000 m2
So 1000 mm of precipitation on an area of 1 hectare is 10,000 liters (or 10,000 tons) of water
or 1000 mm of precipitation is 1000 liters of water per square meter!! !
Accordingly, 1mm of precipitation is 1 liter of water per square meter!!!
Answer from Yoery[guru]
there is such a thing - Molchanov's precipitation gauge, that's where precipitation is measured in millimeters, an ordinary measuring cup from below
Answer from plush cat[master]
According to meteorological guidance, a millimeter of precipitation is one liter of water per square meter. At all weather stations there are rain gauge buckets, from which the observer at 09:00 and 21:00 GMT pours the precipitation that has fallen over a 12-hour period into a special vessel, by which their true amount is measured. Solid precipitation, that is, snow, melts and experts measure the resulting water.
Answer from 3 answers[guru]
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