Atmospheric precipitation and phenomena. Precipitation types

Precipitation - water in liquid or solid state, falling out of clouds or deposited directly from the air on the surface of the Earth. These include:

Rain. The smallest droplets of water, with a diameter of 0.05 to 0.1 mm, which make up the clouds, merging with each other, gradually increase, become heavy and fall to the ground in the form of rain. The stronger the ascending jets of air from the surface heated by the sun, the larger the falling drops should be. Therefore, in summer, when the ground air is heated by the earth and rapidly rises, it usually rains in the form of large drops, and in spring and autumn - drizzling rains. If the rain falls from stratus clouds, then such rain is overflowing, and if from kunevo-rain - shower. Drizzle must be distinguished from rain. This type of precipitation usually falls from stratus clouds. Droplets are much smaller than raindrops. The speed of their fall is so slow that they seem to be suspended in the air.

Snow. It is formed when the cloud is in air with a temperature below 0°. Snow is made up of crystals various forms. Most of the snow falls on the slopes of Rainier (state,) - an average of 14.6 m annually. This is enough to fill a 6-story house.

hail. It occurs when there is a strong updraft of air in warm time of the year. Droplets of water, falling to a great height with air currents, freeze, and ice crystals begin to grow on them in layers. The drops become heavier and begin to fall down. When falling, they increase in size from merging with drops of supercooled water. Sometimes the hail reaches the size chicken egg, usually with different layers in density. As a rule, hail falls from powerful cumulonimbus clouds during or during a downpour. The frequency of hail is different: it happens 10-15 times a year, on land, where there are much more powerful updrafts - 80-160 times a year. Hail falls less frequently over the oceans. Hail brings great material damage: it destroys crops, vineyards, and if hailstones are different large size, then it can cause the destruction of houses, the death of people. Methods for determining hail clouds have been developed in our country and hail control services have been established. dangerous clouds"shoot" with special chemicals.

Rain, snow, hail are called hydrometeorites. In addition to them, precipitation includes those that are deposited directly from the air. These include dew, fog, frost, etc.

Dew(lat. ros - moisture, liquid) - atmospheric precipitation in the form of water droplets deposited on the surface of the earth and ground objects when the air cools. In this case, the water vapor, cooling, changes from a state to a liquid and settles. Most often, dew occurs at night, in the evening or early in the morning.

Fog(Turk, darkness) is an accumulation of small water drops or ice crystals in the lower part of the troposphere, usually near the surface of the earth. sometimes reduce visibility to a few meters. Advective fogs are distinguished by origin (due to the cooling of warm humid air over a colder surface of land or water) and radiation (formed as a result of cooling of the earth's surface). In a number of regions of the Earth, fogs often occur on the coasts in places where cold currents pass. For example, Atacama is located on the coast. Cold weather passes along the coast. Its cold deep waters contribute to the formation of fogs, from which drizzle settles on the coast - the only source of moisture in the Atacama Desert.

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 rain);
• solid precipitation. But they fall out, as you know, at a negative temperature. Such precipitation takes on various shapes (snow of various 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 sun 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.

Atmospheric precipitation is moisture that has fallen to the surface from the atmosphere in the form of rain, drizzle, grains, snow, hail. Precipitation falls from clouds, but not every cloud produces precipitation. Precipitation formation from the clouds are coming due to the coarsening of droplets to sizes that can overcome ascending currents and air resistance. The coarsening of drops occurs due to the merging of drops, the evaporation of moisture from the surface of drops (crystals) and the condensation of water vapor on others.

Precipitation forms:

1. rain - has drops ranging in size from 0.5 to 7 mm (average 1.5 mm);
2. drizzle - consists of small drops up to 0.5 mm in size;
3. snow - consists of hexagonal ice crystals formed in the process of sublimation;
4. snow pellet- rounded nucleoli with a diameter of 1 mm or more, observed at temperatures close to zero. Grains are easily compressed by fingers;
5. ice groats - the nucleoli of the groats have an icy surface, it is difficult to crush them with your fingers, when they fall to the ground they jump;
6. hail - large rounded pieces of ice ranging in size from a pea to 5-8 cm in diameter. The weight of hailstones in some cases exceeds 300 g, sometimes it can reach several kilograms. Hail falls from cumulonimbus clouds.

Types of precipitation:

1. Heavy precipitation - uniform, long in duration, falls from nimbostratus clouds;
2. Heavy rainfall - characterized by a rapid change in intensity and short duration. They fall from cumulonimbus clouds as rain, often with hail.
3. Drizzling precipitation- in the form of drizzle fall out of stratus and stratocumulus clouds.

Distribution of annual precipitation (mm) (according to S.G. Lyubushkin et al.)

(lines on a map connecting points with the same amount of precipitation over a certain period of time (for example, for a year) are called isohyets)

The daily course of precipitation coincides with the daily course of cloudiness. There are two types daily course precipitation - continental and marine (coastal). The continental type has two maxima (in the morning and afternoon) and two minima (at night and before noon). marine type– one maximum (night) and one minimum (day).

The annual course of precipitation varies by different latitudes and even within the same zone. It depends on the amount of heat, thermal regime, air circulation, distance from the coast, the nature of the relief.

Precipitation is most abundant in equatorial latitudes, where their annual amount (GKO) exceeds 1000-2000 mm. On the equatorial islands Pacific Ocean falls 4000-5000 mm, and on the lee slopes of tropical islands up to 10,000 mm. Heavy rainfall is caused by powerful upward currents of very humid air. To the north and south of the equatorial latitudes, the amount of precipitation decreases, reaching a minimum of 25-35º, where the average annual value does not exceed 500 mm and decreases in inland regions to 100 mm or less. AT temperate latitudes the amount of precipitation slightly increases (800 mm). At high latitudes, the GKO is insignificant.

The maximum annual amount of precipitation was recorded in Cherrapunji (India) - 26461 mm. The minimum recorded annual precipitation is in Aswan (Egypt), Iquique - (Chile), where in some years there is no precipitation at all.

Distribution of precipitation on the continents in% of the total

Origin There are convective, frontal and orographic precipitation.

1. convective precipitation are characteristic of the hot zone, where heating and evaporation are intense, but in summer they often occur in the temperate zone.
2. Frontal precipitation formed when two people meet air masses With different temperatures and other physical properties, fall out of warmer air forming cyclonic whirlwinds, are typical of temperate and cold zones.
3. Orographic precipitation fall on the windward slopes of mountains, especially high ones. They are plentiful if air goes from the side warm sea and has high absolute and relative humidity.

Types of precipitation by origin:

I - convective, II - frontal, III - orographic; TV - warm air, HV - cold air.

The annual course of precipitation, i.e. the change in their number by months is not the same in different places on the Earth. It is possible to outline several basic types of annual precipitation patterns and express them in the form of bar charts.

1. equatorial type - Precipitation falls fairly evenly throughout the year, there are no dry months, only after the equinoxes there are two small maximums - in April and October - and after the solstice days two small minimums - in July and January.
2. Monsoon type – maximum precipitation in summer, minimum in winter. It is characteristic of subequatorial latitudes, as well as the eastern coasts of continents in subtropical and temperate latitudes. The total amount of precipitation at the same time gradually decreases from the subequatorial to the temperate zone.
3. mediterranean type - maximum precipitation in winter, minimum - in summer. Observed in subtropical latitudes western coasts and within the continents. Annual rainfall gradually decreases towards the center of the continents.
4. Continental type of precipitation in temperate latitudes - in the warm period, precipitation is two to three times more than in the cold. As the continentality of the climate increases in the central regions of the continents, the total amount of precipitation decreases, and the difference between summer and winter precipitation increases.
5. Marine type of temperate latitudes - Precipitation is distributed evenly throughout the year with a small maximum in autumn and winter. Their number is greater than observed for this type.

Types of annual precipitation patterns:

1 - equatorial, 2 - monsoon, 3 - Mediterranean, 4 - continental temperate latitudes, 5 - maritime temperate latitudes.

Literature

1. Zubashchenko E.M. Regional physical geography. Climates of the Earth: teaching aid. Part 1. / E.M. Zubashchenko, V.I. Shmykov, A.Ya. Nemykin, N.V. Polyakov. - Voronezh: VGPU, 2007. - 183 p.

First of all, let's define the very concept of "atmospheric precipitation". AT " Meteorological Dictionary this term is interpreted as follows: "Precipitation is 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."

According to the above definition, precipitation can be divided into two groups: precipitation released directly from the air - dew, hoarfrost, frost, ice, and precipitation falling from clouds - rain, drizzle, snow, snow pellets, hail.

Each type of precipitation has its own characteristics.

Dew represents the smallest droplets of water deposited on the surface of the earth and on ground objects (grass, leaves of trees, roofs, etc.). Dew forms at night or in the evening on clear, calm weather.

Frost appears on surfaces cooled below 0 °C. It is a thin layer of crystalline ice, the particles of which are shaped like snowflakes.

frost- this is the deposition of ice on thin and long objects (tree branches, wires), formed at any time of the day, usually in cloudy, foggy weather at low temperatures (below - 15 ° C). Hoarfrost is crystalline and granular. On vertical objects, frost is deposited mainly on the windward side.

Among the precipitation released on the earth's surface, of particular importance is ice. It is a layer of dense transparent or cloudy ice that grows on any objects (including trunks and branches of trees, bushes) and on the surface of the earth. It is formed at an air temperature of 0 to -3°C due to the freezing of drops of supercooled rain, drizzle or fog. The crust of frozen ice can reach a thickness of several centimeters and cause branches to break off.

Precipitation falling from the clouds is divided into drizzling, overflowing and torrential.

Drizzling precipitation (drizzle) composed of very fine water droplets less than 0.5 mm in diameter. They are of low intensity. These precipitations usually fall from stratus and stratocumulus clouds. The droplets fall so slowly that they seem to be suspended in the air.

Heavy rainfall- it is rain, consisting of small water droplets, or snowfall from snowflakes with a diameter of 1-2 mm. These are long-term precipitation falling from dense altostratus and nimbostratus clouds. They can last for several hours or even days, capturing vast territories.

heavy rainfall has great intensity. These are large-drop and uneven precipitation, falling both in liquid and solid form (snow, cereals, hail, wet snow). The downpour can last from several minutes to several hours. The area covered by a shower is usually small.

hail, which is always observed during a thunderstorm, usually together with heavy rain, is formed in cumulonimbus (thunderstorm) clouds of vertical development. It usually falls in spring and summer in a narrow band and most often between 12 and 17 hours. The duration of the hail fall is calculated in minutes. Within 5-10 minutes, the ground can be covered with a layer of hailstones several centimeters thick. With intense hail, plants can be damaged to varying degrees or even destroyed.

Precipitation is measured by the thickness of the water layer in millimeters. If 10 mm of precipitation fell, then this means that the layer of water that fell on the surface of the earth is 10 mm. And what does 10 mm of precipitation mean for a plot of 600 m 2? It's easy to calculate. Let's start the calculation for an area equal to 1 m 2. For her, this amount of precipitation will be 10,000 cm 3, i.e. 10 liters of water. And this is a whole bucket. This means that for an area equal to 100 m 2, the amount of precipitation will already be equal to 100 buckets, but for an area of ​​six acres - 600 buckets, or six tons of water. That's what 10 mm of precipitation is for a typical garden plot.

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Precipitation is water that falls from the atmosphere onto the earth's surface. Atmospheric precipitation also has a more scientific name - hydrometeors.

They are measured in millimeters. To do this, measure the thickness of the water that has fallen to the surface with the help of special instruments - precipitation gauges. If it is necessary to measure the water column over large areas, then weather radars are used.

On average, our Earth receives almost 1000 mm of precipitation annually. But it is quite predictable that their amount of moisture that has fallen out depends on many conditions: the climate and weather conditions, the terrain, and the proximity of water bodies.

Types of precipitation

Water from the atmosphere falls to the earth's surface, being in its two states - liquid and solid. According to this principle, all atmospheric precipitation is usually divided into liquid (rain and dew) and solid (hail, frost and snow). Let's consider each of these types in more detail.

Liquid precipitation

Liquid precipitation falls to the ground in the form of water droplets.

Rain

Evaporating from the surface of the earth, water in the atmosphere collects into clouds, which consist of tiny drops, ranging in size from 0.05 to 0.1 mm. These tiny droplets in the clouds merge with each other over time, becoming larger and noticeably heavier. Visually, this process can be observed when the snow-white cloud begins to darken and become heavier. When there are too many such drops in the cloud, they spill onto the ground in the form of rain.

Summer it's raining in the form of large drops. They remain large because the heated air rises from the ground. It is these ascending jets that do not allow drops to break into smaller ones.

But in spring and autumn, the air is much cooler, so at these times of the year the rains are drizzling. Moreover, if the rain comes from stratus clouds, it is called oblique, and if the drops begin to fall from the kune-rain, then the rain turns into a downpour.

Almost 1 billion tons of water is poured onto our planet every year in the form of rain.

It is worth highlighting in a separate category drizzle. This type of precipitation also falls from stratus clouds, but its drops are so small and their speed is so negligible that the water droplets seem to be suspended in the air.

Dew

Another type of liquid precipitation that falls at night or early in the morning. Dew drops are formed from water vapor. During the night, this vapor cools, and the water turns from a gaseous state into a liquid one.

The most favorable conditions for the formation of dew: clear weather, warm air and almost no wind.

Solid atmospheric precipitation

We can observe solid precipitation during the cold season, when the air cools to such an extent that the water droplets in the air freeze.

Snow

Snow, like rain, forms in clouds. Then, when the cloud enters a stream of air in which the temperature is below 0 ° C, the water droplets in it freeze, become heavy and fall to the ground in the form of snow. Each drop freezes in the form of a kind of crystal. Scientists say that all snowflakes have different shape and it is simply impossible to find the same.

By the way, snowflakes fall very slowly, since they are almost 95% air. For the same reason they are white. And the snow crunches underfoot because the crystals break. And our ears are able to pick up this sound. But for fish, this is a real torment, since snowflakes falling on the water emit a high-frequency sound that fish hear.

hail

falls only in the warm season, especially if it was very hot and stuffy the day before. The heated air rushes up in strong streams, carrying the evaporated water with it. Heavy Cumulus clouds. Then, under the influence of ascending currents, the water droplets in them become heavier, begin to freeze and grow into crystals. It is these lumps of crystals that rush to the ground, increasing in size along the way due to merging with drops of supercooled water in the atmosphere.

It should be borne in mind that such ice "snowballs" rush to the ground with incredible speed, and therefore hail is able to break through slate or glass. Hail causes great damage to agriculture, so the most "dangerous" clouds that are ready to burst into hail are dispersed with the help of special guns.

Frost

Hoarfrost, like dew, is formed from water vapor. But in winter and autumn months When it is already cold enough, the water droplets freeze and therefore fall out as a thin layer of ice crystals. And they do not melt because the earth cools even more.

rainy seasons

In the tropics, and very rarely in temperate latitudes, there comes a time of the year when an unreasonably large amount of precipitation falls. This period is called the rainy season.

In countries that are located in these latitudes, there is no harsh winters. But spring, summer and autumn are incredibly hot. During this hot period, a huge amount of moisture accumulates in the atmosphere, which then pours out in the form of prolonged rains.

At the equator, the rainy season occurs twice a year. And in the tropical zone, south and north of the equator, such a season happens only once a year. This is due to the fact that the rain belt gradually runs from south to north and back.