Short-term precipitation. What is precipitation? Definition and types. Why doesn't it always rain on cloudy days?

PRECIPITATION

PRECIPITATION, in meteorology, all forms of water, liquid or solid, that fall out of the atmosphere onto the earth. Precipitation differs from CLOUD, FOG, DEW and FROST in that it falls and reaches the ground. Includes rain, drizzle, SNOW and hail. They are measured by the thickness of the layer of precipitated water and are expressed in millimeters. Precipitation occurs due to the CONDENSATION of cloud water vapor into small water particles, which merge into large drops with a diameter of about 7 mm. Precipitation also forms from melting ice crystals in clouds. Drizzle consists of very small droplets, and snow - of ice crystals, mainly in the form of hexagonal plates and six-pointed stars. Groats formed when raindrops freeze and turn into small ice balls, and hail - when concentric layers of ice in cumulonimbus clouds freeze, forming fairly large rounded pieces irregular shape, from 0.5 to 10 cm in diameter.

Precipitation. Thin clouds and clouds in the tropics do not reach freezing height, so ice crystals do not form in them (A). Instead, a larger-than-usual water particle in a cloud can combine with several million other water particles, resulting in the size of a raindrop. Electric charges can promote the association of water particles if they have opposite charges. Some of the droplets break apart, forming water particles large enough to start a chain reaction that creates a stream of raindrops. Most of the rainfall in the middle latitudes, however, is the result of falling snow flakes melting before they reach the ground (B). Many millions of small water particles and ice crystals must combine to form a single drop or snowflake, heavy enough to fall from the cloud to the ground. However, a snowflake can grow from ice crystals in as little as 20 minutes. In order to form large hailstones, strong air currents (C) are required (hailstones with a diameter of 30 mm are formed at an air velocity of 100 km/h). Vortex air currents during a thunderstorm turn frozen water particles into initial hailstones. Abundant supercooled wet water particles easily freeze to its surface. The hailstone is thrown from side to side by air currents, as a result of which numerous dense layers of ice are concentrated on it, which can be transparent or white. An opaque layer is formed when air bubbles, and sometimes ice crystals, enter the hailstone during rapid freezing in the cold upper tiers of the cloud. Transparent layers form in the warmer lower layers of the cloud, where the water freezes much more slowly. There can be up to 25 or more layers (D) in a hailstone, with the last - a transparent layer of ice, often the thickest - formed when the hailstone falls through the moist and warm lower the edge of the cloud. The largest hailstone was registered on September 3, 1970 in Coffeeville, Kansas. Its diameter was 190 mm, and its weight was 766 g.

Scientific and technical encyclopedic Dictionary .

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Modern Encyclopedia

Atmospheric water in liquid or solid state (rain, snow, grains, ground-based hydrometeors, etc.) falling out of clouds or deposited from the air on earth's surface and on objects. Precipitation is measured by the thickness of the layer of precipitated water in mm. IN… … Big Encyclopedic Dictionary

Groats, snow, drizzle, hydrometeor, lotions, rain Dictionary of Russian synonyms. precipitation n., number of synonyms: 8 hydrometeor (6) ... Synonym dictionary

Precipitation- atmospheric, see Hydrometeors. Ecological encyclopedic dictionary. Chisinau: Main edition of the Moldavian Soviet encyclopedia. I.I. Grandpa. 1989. Precipitation water coming from the atmosphere to the earth's surface (in liquid or solid ... Ecological dictionary

Precipitation- atmospheric, water in a liquid or solid state, falling out of clouds (rain, snow, grain, hail) or deposited on the earth's surface and objects (dew, frost, hoarfrost) as a result of condensation of water vapor in the air. Precipitation is measured ... ... Illustrated Encyclopedic Dictionary

In geology, loose formations deposited in a suitable environment as a result of physical, chemical and biological processes ... Geological terms

PRECIPITATION, ov. Atmospheric moisture that falls to the ground in the form of rain or snow. Abundant, weak o. No precipitation today (no rain, no snow). | adj. sedimentary, oh, oh. Dictionary Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

- (meteor.). This name is used to denote the moisture that falls on the surface of the earth, being isolated from the air or from the soil in liquid or solid form. This release of moisture occurs every time water vapor is constantly ... ... Encyclopedia of Brockhaus and Efron

1) atmospheric water in a liquid or solid state, falling out of clouds or deposited from the air on the surface of the earth and on objects. O. falls out of the clouds in the form of rain, drizzle, snow, sleet, snow and ice pellets, snow grains, ... ... Emergencies Dictionary

PRECIPITATION- meteorological, liquid and solid bodies released from the air onto the surface of the soil and solid objects due to the condensation of water vapor contained in the atmosphere. If O. fall from a certain height, then hail and snow are obtained for rain; if they… … Big Medical Encyclopedia

Books

• Precipitation and thunderstorms from December 1870 to November 1871, A. Voeikov. Reproduced in the original author's spelling of the 1875 edition (publishing house `St. Petersburg`). IN…

Rain, snow or hail - we have been familiar with all these concepts since childhood. We have a special relationship with each of them. So, rain evokes sadness and dull thoughts, snow, on the contrary, amuses and cheers up. But hail, for example, few people love, as it can cause enormous damage to agriculture and serious injuries to those who find themselves on the street at this time.

We have long since learned how to outward signs determine the approach of certain precipitation. So, if in the morning it is very gray and cloudy outside, precipitation in the form of prolonged rain is possible. Usually such rain is not very heavy, but can last all day. If thick and heavy clouds appear on the horizon, precipitation in the form of snow is possible. Light clouds in the form of feathers portend heavy rain showers.

It should be noted that all types of precipitation are the result of very complex and very long processes in the earth's atmosphere. So, in order to form ordinary rain, the interaction of three components is necessary: ​​the sun, the surface of the Earth and the atmosphere.

Precipitation is...

Precipitation is water in liquid or solid state that falls out of the atmosphere. Precipitation can either fall on the surface of the Earth directly or settle on it or on any other objects.

The amount of precipitation in a particular area can be measured. They are measured by the thickness of the water layer in millimeters. In this case, solid types of precipitation are pre-melted. The average amount of precipitation per year on the planet is 1000 mm. In no more than 200-300 mm falls, and the driest place on the planet is where the recorded annual precipitation is about 3 mm.

Education process

How are they formed, different types of precipitation? The scheme of their formation is one, and it is based on continuous Let us consider this process in more detail.

It all starts with the fact that the Sun begins to warm up Under the influence of heating water masses, which are contained in the oceans, seas, rivers, are converted into mixing with air. Vaporization processes occur throughout the day, constantly, to a greater or lesser extent. The volume of vaporization depends on the latitude of the area, as well as on the intensity of solar radiation.

Further wet air heats up and begins, according to the immutable laws of physics, to rise up. Having risen to a certain height, it cools, and the moisture in it gradually turns into drops of water or ice crystals. This process is called condensation, and it is these water particles that make up the clouds that we admire in the sky.

Droplets in the clouds grow and become larger, taking in more and more moisture. As a result, they become so heavy that they can no longer be held in the atmosphere, and fall down. That's how they are born precipitation, the types of which depend on specific weather conditions in a particular area.

The water that falls on the surface of the Earth eventually flows in streams into rivers and seas. Then the natural cycle repeats over and over again.

Atmospheric precipitation: types of precipitation

As already mentioned here, there are a huge number of varieties precipitation. Meteorologists distinguish several dozen.

All types of precipitation can be divided into three main groups:

• drizzling;
• overlay;
• storm.

Precipitation can also be liquid (rain, drizzle, fog) or solid (snow, hail, frost).

Rain

This is a type of liquid precipitation in the form of water droplets that fall to the ground under the influence of gravity. The size of the droplets can be different: from 0.5 to 5 millimeters in diameter. Raindrops, falling on the water surface, leave diverging circles of perfectly round shape on the water.

Depending on the intensity, the rain can be drizzling, patchy or torrential. There is also a type of precipitation such as rain with snow.

This special kind atmospheric precipitation, which occur at sub-zero air temperatures. They should not be confused with hail. freezing rain It is a droplet in the form of small frozen balls, inside of which there is water. Falling to the ground, such balls break, and water flows out of them, leading to the formation of dangerous ice.

If the intensity of the rain is too high (about 100 mm per hour), then it is called a downpour. Showers form on cold atmospheric fronts, within unstable air masses. As a rule, they are observed in very small areas.

Snow

These solid precipitations fall at sub-zero air temperatures and take the form of snow crystals, colloquially referred to as snowflakes.

During snow, visibility is significantly reduced, with heavy snowfall it can be less than 1 kilometer. During severe frosts light snow can be observed even with a cloudless sky. Separately, such a type of snow as sleet stands out - this is precipitation that falls at low positive temperatures.

hail

This type of solid atmospheric precipitation is formed on high altitudes(at least 5 kilometers), where the air temperature is always lower - 15 o.

How is hail produced? It is formed from drops of water that either fall or rise sharply in eddies of cold air. Thus, large ice balls are formed. Their size depends on how long these processes took place in the atmosphere. There were cases when hailstones weighing up to 1-2 kilograms fell on the ground!

A hailstone in its internal structure is very similar to an onion: it consists of several layers of ice. You can even count them, like you count the rings on a cut tree, and determine how many times the droplets have made rapid vertical journeys through the atmosphere.

It is worth noting that hail is a real disaster for Agriculture, because he can easily destroy all the plants on the plantation. In addition, it is almost impossible to determine the approach of hail in advance. It starts instantly and happens, as a rule, in the summer season of the year.

Now you know how precipitation is formed. The types of precipitation can be very different, which makes our nature beautiful and unique. All the processes taking place in it are simple, and at the same time ingenious.

Anyone who has children knows very well how many different “whys” you have to answer daily. Just recently, I had to spend a whole lesson with my son on this topic.

How clouds and precipitation form

One of the most important and unique atmospheric properties our planet - enough steam for cloud formation. weather in more characterized by whether there are clouds in the sky, if the weather is dry, or it's raining. But where does all the water that becomes rain come from, and how is it kept in the air? Everyone knows that precipitation falls from clouds, and if you fly a plane above them, you can see bright sun. How are clouds formed?

The vapor in the air is invisible, but when the temperature drops environment it condenses, and then we see clouds. In fact, Precipitation is solid or liquid water that falls from clouds. or settling on the surface of objects or the earth. This is the result of the condensation of water vapor in the air. The evaporation process is ongoing, regardless of what temperature the thermometer outside the window shows. The only difference is that the higher the temperature, the more intense this process is.

What are the clouds

Regarding the height, the following clouds are distinguished:

• lower tier- their height is small, about 2000 meters;
• middle tier- the height of their "flight" from 2000 to 7000 meters;
• upper tier occupy clouds whose height is not less than 7000 meters;
• vertical development cloud observed at an altitude of less than 2000 meters.

Precipitation classification

There is quite extensive classification this natural phenomenon and therefore I will briefly describe main types. When the nature of origin is implied, a distinction is made:

• orographic- observed on mountain slopes and are abundant;
• frontal- are the result of a meeting of air masses of different temperatures;
• convective- occur due to the intense heating of the earth's surface and, consequently, abundant evaporation.

Concerning the nature of the fallout, there are the following types:

• drizzling- small droplets in a small area;
• obligatory- rather long, and cover impressive territories;
• storm- characterized by short duration, but covering not large area fall out the most.

Absolute maximum and minimum

The record for rainfall is islands of Hawaii - 11748 mm / year. Opposite value - minimum, fixed in the Libyan desert - less than 40 mm / year. At the same time, there may be no precipitation for many years.

Surely, each of us has ever watched the rain through the window. But have we thought about what kind of processes occur in rain clouds? What types of precipitation can receive? That is what got me interested. I opened my favorite home encyclopedia and settled on the section titled "Types of Precipitation". What was written there, I'm going to tell.

What are the precipitation

Any precipitation falls due to the enlargement of elements in the clouds (for example, water droplets or ice crystals). Having increased to a size at which they can no longer be in suspension, the drops fall down. Such a process is called "coalescence"(which means "fusion"). And the further growth of drops occurs already in view of their merging in the process of falling.

Atmospheric precipitation often takes quite different types. But in science there are only three main groups:

• massive precipitation. These are the precipitations that usually fall during very long period with medium intensity. Such rain covers the largest area itself and falls from special nimbostratus clouds that cover the sky, not letting in light;
• rainfall. They are the most intense, but short-lived. Originate from cumulonimbus clouds;
• drizzling rain. They, in turn, are made up of small droplets - drizzle. This kind of rain can last a very long time. for a long time. Drizzling precipitation falls from stratus (including stratocumulus) clouds.

In addition, precipitation is divided according to their consistency. This is what will be discussed now.

Other types of precipitation

Additionally, the following types of precipitation are distinguished:

• liquid precipitation. Basic. It was about them that was mentioned above (overlapping, torrential and drizzling types of rains);
• solid precipitation. But they fall out, as you know, at a negative temperature. Such precipitation takes on various shapes (snow of the most different forms, hail and so on...);
• mixed precipitation. Here the name speaks for itself. An excellent example is a cold freezing rain.

These are the different types of precipitation. And now it is worth making some interesting remarks about their loss.

The shape and size of snowflakes are determined by the temperature in the atmosphere and the strength of the wind. The purest and driest snow on the surface is capable of reflecting about 90% light from the sun's rays.

More intense and larger (in the form of drops) rains occur on small areas. There is a relationship between the size of territories and the amount of precipitation.

The snow cover is able to independently emit thermal energy, which, nevertheless, quickly escapes into the atmosphere.

Clouds with clouds have huge weight. More than 100 thousand km³ of water.

The main factor that has a significant impact on the progress of the flora and fauna of planet Earth is the presence of a climate favorable for the development of life (temperature, humidity, various types of precipitation).

From this list, it is atmospheric phenomena that create numerous climatic zones, which, in turn, are distinguished by a variety of life forms.

All precipitation is inextricably linked with the water cycle in nature - this includes all phenomena that are formed on the basis of the physicochemical properties of water and its ability to be in three states of aggregation - liquid, solid and vapor (3 types of precipitation).

At school, this topic is taught in the 2nd grade in the subject "World around".

What is precipitation

A strict definition of precipitation in geography is usually given as follows. This term refers to such phenomena that occur in the Earth's atmosphere, which are based on the concentration of water in air layer, and are also associated with the transition of water dispersion into various states of aggregation and precipitation onto the surface of the planet.

The main classification of precipitation is division by temperature of atmospheric fronts:

• obligatory– associated with warm air currents;
• storm associated with cold air masses.

To account for the amount of precipitation that falls on the Earth's surface in a certain region, meteorologists use special equipment - rain gauges, which provide data measured in the thickness of the layer of liquid water that has fallen on a solid surface. The units of measurement are millimeters per year.

Natural precipitation plays a key role in the formation of the earth's climate and forms the circulation of water in nature.

Types of precipitation

It is possible to conditionally divide the types of precipitation on the basis of the state of aggregation of water in which it enters the Earth. In principle, this is possible in only two versions - solid and liquid form.

Based on this, the classification is as follows:

• liquid- (rain and dew);
• solid- (snow, hail and frost).

Let's figure out what each type of such precipitation represents.

The most common type of precipitation is rain(applies to convective precipitation). This phenomenon is formed under the influence of the radiant energy of the Sun, which heats the moisture on the surface of the Earth and evaporates it.

Getting into the upper layers of the atmosphere, which are noticeably colder, water condenses, forming a cluster of tiny droplets. As soon as the amount of condensate reaches a large mass, the water spills onto the ground in the form of heavy rain.

Types of rain are classified according to the size of the drops, which in turn is related to the currents and air temperature.

A variety of rains is formed as follows - if the air is warm, then it forms larger drops, and if it is cold, then drizzling light rain (supercooled rain) can be observed. When the temperature drops, it rains with snow.

Another process related to condensation is dew drop. This physical phenomenon It is based on the fact that a certain volume of air can contain a strictly defined amount of steam at a given temperature.

Until the limiting volume of vapor is reached, condensation does not occur, but as soon as the amount exceeds the desired value, the excess precipitates into a liquid state. We can observe this in the early morning on the street, looking at the dew, flowers and other solid objects.

Another common type of precipitation is snow. In principle, its formation is similar to the formation of rain, however, rain differs from snow in that when it falls on the ground, the drops are significantly cooled by air jets that have a negative temperature, and microscopic ice crystals form.

Since the process of formation of snowflakes occurs in the air and under the influence of different temperature, then this causes a large number of shapes and crystals of snowflakes.

If the temperature is very low, then blanket snow forms, if it is closer to zero, then heavy snow. Wet snow forms at temperatures slightly above freezing.

One of the dangerous atmospheric phenomena- This deg. Its formation occurs mainly in summer, when heated air flows carry vaporous moisture to the upper layers of the atmosphere, where, supercooling, the water freezes, forming ice pieces.

They do not have time to melt when flying to the earth's surface and are often the cause of the destruction of crops or damage to buildings.

Condensation of water from steam is also possible in winter. Basically, this is due to low rate relative humidity air.

At the same time, given the negative temperature, the condensed moisture immediately freezes on solid surfaces, forming frost.

Types of precipitation by seasons of the year

Often a characteristic based on the seasonality of precipitation is used.

So, there are:

• precipitation falling mainly during the warm season- rain, drizzle (subtype of rain), dew, hail;
• precipitation that occurs during the cold season- snow, groats (a subspecies of snow), hoarfrost, frost, ice.

Types of precipitation by formation height

More accurate is the classification, which takes into account at what height the condensate turned into one of the types of precipitation:

• precipitation that forms in the upper and middle layers of the atmosphere includes rain, drizzle, hail, grains and snow - falling from clouds;
• Precipitation that forms in the immediate vicinity of the earth's surface (orographic precipitation) includes mainly condensation phenomena (examples - dew, hoarfrost, frost and ice) - falling out of the air.

How precipitation is measured

Often in the weather forecast you can hear that 2 millimeters of precipitation fell per day. Such data are determined by meteorologists and weather forecasters at weather stations using special equipment - precipitation gauges.

These are graduated buckets (on which conventional signs), made in a certain standard size, which are installed on the street.

Every day, in the time interval from 9-00 to 21-00 (time is taken according to the GMT 0 time zone), the meteorologist collects all the moisture that accumulates in the bucket and pours it into a graduated cylinder (cylinder divisions are made in mm).

The obtained values ​​are recorded in the log book, forming a table of precipitation. If the precipitates were solid, then it is allowed to melt them.

To build a visual picture, points with measured precipitation are marked on the map. These points are connected into a diagram by lines - isohyets, and the space is painted over with the colors of precipitation with increasing intensity.

How precipitation affects aviation operations

There are a number of very important atmospheric factors that hinder the operation of aviation. First of all, it is connected with ensuring flight safety.

The main ones are:

1. First of all, this is a deterioration in visibility for aircraft pilots. Reduced visibility in heavy rain or a snowstorm occurs up to 1.5-2 km, which makes it difficult to visually control the course.
2. During takeoff or landing, moisture condensation on windows or optical reflectors can lead to a distorted perception of information by the pilot.
3. A large amount of water fine dust, if it enters the engine, can make it difficult and disrupt its operation.
4. When the aerodynamic elements of the aircraft (wings, steering elements) are iced, there is a loss of flight characteristics.
5. When a significant amount of precipitation falls, contact with the runway coating is difficult.

Thus, all precipitation, in relation to aviation, is extremely unfavorable.

Precipitation is a key factor contributing to the formation of the Earth's climate, as well as geographical areas. Conditional division is carried out depending on seasonality, however, it should be remembered that combinations can occur in the off-season. Also, precipitation is essential element water circulation on the planet.