Information about the types of precipitation. Classification, types and types of climatic precipitation

Precipitation called drops of water and ice crystals falling from clouds or settling from the air to the earth's surface. Precipitation from clouds provides more than 99% of the total amount of water coming from the atmosphere to the earth's surface; less than 1% is precipitation from the air.

Precipitation x is characterized by quantity and intensity. Precipitation measured by the thickness (expressed in mm or cm) of the layer of water they would form on the surface of the earth in the absence of seepage, runoff and evaporation. Intensity - this is the amount of precipitation falling per unit of time (per minute or per hour).

Necessary condition For the formation of precipitation is the enlargement of cloud elements to such a size, at which the rate of fall of these elements becomes greater than the rate of ascending flows. The consolidation process occurs mainly for the following reasons:

a) due to the recondensation of water vapor from water droplets to ice crystals or from

small drops into large ones. This is because the saturation elasticity over ice crystals is less than over water drops, and over large drops is less than over small ones.

b) due to the merging (coagulation) of water drops during their collision as a result of turbulent air movements and different falling velocities of large and small drops. These collisions lead to the absorption of small droplets by large ones.

Droplet growth due to condensation prevails until the droplet radius becomes 20–60 µm, after which coagulation becomes the main process of cloud element enlargement.

Clouds of varnish that are homogeneous in their structure, i.e. consisting only of the same

droplet sizes or only from ice crystals, do not give precipitation. Such clouds include cumulus and altocumulus, consisting of small water droplets, as well as cirrus, cirrocumulus and cirrostratus, consisting of ice crystals.

In clouds consisting of droplets of different sizes, larger drops slowly grow at the expense of smaller ones. However, as a result of this process, only small drops of rain are formed. Such a process occurs in stratus and sometimes in stratocumulus clouds, from which precipitation can fall in the form of drizzle.

c) the main types of precipitation fall from mixed clouds, in which cloud elements grow larger due to the freezing of supercooled droplets on ice crystals. The enlargement of cloud elements proceeds rapidly and is accompanied by rain or snow. These clouds include cumulonimbus, nimbostratus, and altostratus.

Precipitation from clouds can be liquid, solid or mixed.

The main forms of precipitation are:

Wet snow– precipitation consisting of melting snow at a temperature of – 0°…+5°С.

snow grits- soft milky-white opaque round-shaped grains with a diameter of 2 ... 5 mm.

hail– precipitation in the form of pieces of ice of various sizes. Hailstones have an irregular or spherical (close to spherical) shape, their size ranges from 5 mm to 10 cm or more. Therefore, the weight of hailstones can be very large. In the center of the hailstones there is a whitish translucent grain covered with several layers of transparent and opaque ice.

freezing rain – small transparent spherical particles with a diameter of 1…3 mm. They are formed when raindrops freeze, falling through the lower layer of air with a negative temperature (rain at a temperature of 0° ... 5°C).

According to the nature of the drop, depending on the physical conditions education,

duration and intensity, precipitation is divided into three types:

1. Heavy rainfall - these are long-term, medium-intensity precipitation in the form of rain drops or snow flakes, which are observed simultaneously over a large area. These precipitations fall from the system of frontal nimbostratus and altostratus clouds.

2. heavy rainfall - these are short-term, high intensity and precipitation in the form of large drops, large snow flakes, sometimes ice pellets or hail, which are usually observed over small areas. They fall out of cumulonimbus, and sometimes powerful cumulus (in the tropics) clouds. Usually they begin suddenly, do not last long, but in some cases they can be repeatedly renewed. Heavy rainfall is often accompanied by thunderstorms and squalls.

3. Drizzling precipitation - very small drops, the smallest snowflakes or snow grains, settling from the clouds to the ground almost imperceptibly to the eye. They are observed simultaneously over a large area, their intensity is very low and is usually determined not by the amount of precipitation, but by the degree of deterioration of horizontal visibility. They fall out of stratus and stratocumulus clouds.

Precipitation released directly from the air include: dew, frost, frost, liquid or solid deposits on the windward side of vertically arranged objects.

Dew- this is liquid precipitation in the form of small droplets of water that form on summer nights and in the morning on objects located near the surface of the earth, plant leaves, etc. Dew forms on contact humid air with cooled objects, due to which water vapor condenses.

Frost- this is a white fine-crystalline deposit formed as a result of the sublimation of water vapor in those cases when the temperature of the surface air and the underlying surface is below 0°C;

High moisture content, slightly cloudy weather and weak wind contribute to the formation of dew and hoarfrost. This process involves a layer of air with a thickness

200 ... 300 m and more. Frost that forms on the surface of an aircraft on the ground must be carefully removed before departure, as this can lead to serious consequences due to the deterioration of the aerodynamic qualities of the aircraft.

frost It is white, loose, snow-like ice. It is formed in foggy frosty weather with a very weak wind on the branches of trees and shrubs, wires and other objects. The formation of frost is mainly associated with the freezing of the smallest supercooled droplets colliding with various objects. The snowy bang of rime rime can be the most bizarre shape. It easily crumbles when shaken off, but with an increase in temperature and a new cold snap, it can freeze and freeze.

Liquid and solid plaque It is formed on the windward part and vertically located objects cooled to a temperature below the ambient air temperature. In warm weather, a liquid coating is formed, and at surface temperatures below 0°C, white translucent ice crystals are formed. This type of precipitation can form at any time of the day with sharp warming in the cold season.

Snowstorms are a special form of precipitation transport. There are three types of blizzards:

snow drift, blowing snow, and general snowstorm.

snow drift and blowing snow are formed during the transfer of dry snow over the surface of the earth. A snow drift is formed when the wind is 4…6 m/s, the snow rises to heights up to 2 m above the ground. A blowing snow blizzard is formed when the wind is 6 m / s or more, the snow rises to a height of more than 2 m above the ground. At common blizzard (does not have its own icon) there is snowfall from the clouds, wind of 10 m/s or more, the rise of previously fallen snow from the ground and visibility less than 1000 m.

All types of precipitation complicate flight operations. The effect of precipitation on flights depends on their type, the nature of precipitation and air temperature.

1. In precipitation, visibility deteriorates and the lower boundary of the clouds decreases. In moderate rain, when flying e at low speed, horizontal visibility deteriorates to 4 ... 2 km, and when high speed flight - up to 2 ... 1 km. A significant deterioration in horizontal visibility is observed when flying in a snowfall zone. In light snow, visibility usually does not exceed 1–2 km, and in moderate and heavy snow it deteriorates to several hundred meters. In torrential precipitation, visibility deteriorates sharply to several tens of meters. The lower boundary of the clouds in the precipitation zone, especially on atmospheric fronts, drops to 50...100 m and can be located below the decision height.

2. Precipitation in the form of hail causes mechanical damage to aircraft. At high speed and flight, even small hailstones can make significant dents and destroy the cockpit glazing. Hail is sometimes found at a considerable height: small hail is observed at a height of about 13 km, and large hail is observed at a height of 9.5 km. The destruction of the glazing at a high altitude can lead to depressurization, which is very dangerous.

3. When flying in a freezing rain zone, intense icing is observed

aircraft.

4. Prolonged heavy precipitation in the warm season a causes waterlogging of the soil and puts unpaved airfields out of action for one time or another, disrupts the regularity of departure and reception of aircraft.

5. Heavy rainfall degrades the aerodynamic qualities of the aircraft, which can lead to stall. In this regard, they landed in heavy rainfall with a visibility of less than 1000 m forbidden .

6. When flying on VFR in the snowfall zone over a snowy surface, the contrast of all objects on the ground is significantly reduced. earth's surface and therefore the orientation deteriorates greatly.

7. When landing on a wet or snow-covered runway, the length of the aircraft run increases. Slip on a runway covered with snow is 2 times greater than on a concrete runway.

8. When an aircraft takes off from a runway covered with slush, hydroplaning may occur. The wheels of the aircraft throw off powerful jets of water and slush, there is a strong deceleration and an increase in the length of the takeoff run. Conditions may be created that the aircraft will not reach liftoff speed and a dangerous situation will arise.

9. Drop-in winter time snow requires additional work on its cleaning and compaction on runways, taxiways and parking lots where aircraft and other machines and mechanisms are serviced.

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 appeared 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 that it is formed regular rain, the interaction of three components is necessary: ​​the sun, the Earth's surface 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. Wherein solid types precipitation is 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 they are formed different kinds 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, the water masses that 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, moist 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. This is how atmospheric precipitation is born, 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 is great amount 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 is a special type of precipitation that occurs at sub-zero air temperatures. They should not be confused with hail. Freezing rain is drops 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 precipitation fall out at sub-zero air temperatures and look like 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 kind of solid atmospheric precipitation is formed at high altitudes (at least 5 kilometers), where the air temperature is always lower - 15 ° C.

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.

In meteorology, precipitation is divided into the following types:

Rain- liquid drop precipitation (droplet diameter is usually 0.5-0.7 mm, sometimes more) .

drizzle- precipitation consisting of small homogeneous cough (diameter 0.05-0.5 mm), falling imperceptibly to the eye.

freezing rain- precipitation in the form of ice balls (diameter from 1 to 3 mm).

hail- precipitation having pieces of ice of various sizes and shapes (diameter from 4-5 to 50 mm, sometimes more).

Snow- solid precipitation in the form of crystals, stars or flakes.

Wet snow- Precipitation in the form of melting snow with rain. Snow groats - precipitation in the form of white round snow balls (diameter from 2 to 5 mm).

snow grains- small snow grains (diameter less than 1 cm).

ice needles- thin ice sticks in suspension, sparkling in the sun of a frosty day.

According to the nature of precipitation, they are divided into three types: continuous, torrential and drizzling (drizzle).

Heavy rainfall fall out of nimbostratus and altostratus clouds for a long time over a large area. Their intensity ranges from 0.5 to 1 mm/min. Heavy precipitation may fall in the form of rain and snow (sometimes wet).

heavy rainfall fall out of cumulonimbus clouds in a limited area in in large numbers and in a short period of time. Their intensity is from 1 to 3.5 mm/min and more (there were showers in the Hawaiian Islands - 21.5 aphids min). Heavy rainfall is often accompanied by thunderstorms and squalls. As well as overburden, torrential precipitation can fall in the form of rain and snow. In the latter case, they are called "snow charges".

Drizzling precipitation (drizzle) are small droplets (snowflakes) with a very low falling speed. Fall out of stratus clouds or fog. Their intensity is insignificant (less than 0.5 mm/min).

Blizzard is a special form of precipitation. During a snowstorm, the wind carries snow along the earth's surface for long distances. A blizzard occurs when the wind is strong enough. There are three types of snowstorms: general (with heavy snowfall and wind from 7 m/s), grassroots (without snowfall, with a wind of 10-12 m/s) and drifting snow (without snowfall, with wind 6 m/s and more).

Precipitation measurement

The amount of precipitation is measured rain gauge, which is a bucket closed with a grate, mounted on a pole and protected from the wind by a special device. The precipitation is poured into a beaker and measured. The amount of precipitation is expressed as the height of the water layer in millimeters, formed as a result of precipitation on a horizontal surface in the absence of evaporation, seepage and runoff.

Usually taken into account amount of precipitation per day, as well as monthly, seasonal and annual precipitation totals. Precipitation intensity is the amount of precipitation in millimeters that falls in one minute (mm/min). The amount of snowfall is determined by measuring the height of the snow cover in centimeters from the ground using snow gauge with centimeter divisions.

Impact of precipitation on aviation operations

Precipitation has an extremely adverse effect on the operation of aviation, namely:

In precipitation, visibility from the aircraft deteriorates. In light to moderate rain or light snow, horizontal visibility deteriorates to 4-2 km, and at high flight speed - up to 1-2 km. In heavy rain, as well as during moderate and heavy snowfall, visibility deteriorates sharply to several tens of meters.

In addition, the water film on the glass of the aircraft cabin canopy causes optical distortion of visible objects, which is dangerous during takeoff and especially during landing.

In flight in the precipitation zone, in addition to the deterioration of visibility, there is a decrease in the height of the clouds.

In heavy rain, the speed indicator readings may be too low, sometimes up to 100 km/h This happens due to partial blocking of the opening of the air pressure receiver by drops of water.

Rainfall can get into the engine and make it difficult or impair its operation.

In flight, in the zone of supercooled rain, very dangerous intense icing of the aircraft occurs.

Precipitation has a significant impact on the condition and operation of aerodromes:

The presence of precipitation on the runway reduces the coefficient of friction, which worsens the controllability on the runway and increases the length of the takeoff run and run.

Water, snow, slush thrown by the nose or main wheels can be sucked into the engines, causing damage to their structure or loss of thrust, clogging of small air intakes, slots in controls, mechanization, landing gear, various doors and hatches, SHS receivers is possible, which leads to obstruction or damage to relevant aircraft systems.

Prolonged or torrential rains can lead to soaking of unpaved airfields.

The snow cover formed at the aerodrome due to snowfalls requires special work on its removal or rolling to ensure normal flights.

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 overcast, and if it falls from kuni-nimbo clouds, it is 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 with strong ascending air currents in the warm season. 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 the hailstones are large in size, it can also cause the destruction of houses and death of people. Methods for determining hail clouds have been developed in our country and hail control services have been established. Dangerous clouds are "shot" 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. There are advective fogs (due to the cooling of warm moist air over a colder surface of land or water) and radiation fogs (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.

Precipitation

Atmospheric precipitation called 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. The formation of precipitation from the cloud is due to the coarsening of droplets to a size 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.

By state of aggregation produce liquid, solid and mixed precipitates.

To liquid precipitation includes rain and drizzle.

ü rain - has drops ranging in size from 0.5 to 7 mm (average 1.5 mm);

ü drizzle - consists of small drops up to 0.5 mm in size;

To solid refer snow pellets and ice pellets, snow and hail.

ü snow groats - rounded nucleoli with a diameter of 1 mm or more, observed at temperatures close to zero. Grains are easily compressed by fingers;

ü 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;

ü snow - consists of hexagonal ice crystals formed in the process of sublimation;

ü 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: (according to the nature of precipitation)

1. Heavy rainfall- uniform, long in duration, fall out of 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.

The daily course of precipitation coincides with the daily course of cloudiness. There are two types daily course precipitation - continental and marine (coastal). 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, remoteness 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 leeward slopes 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 ah, 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.

Origin There are convective, frontal and orographic precipitation.

1. Convective precipitation (intramass) 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 the air comes 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. change in their number by months, in different places The earth is not the same. Precipitation on the earth's surface is distributed zonal.

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. At the same time, the total amount of precipitation gradually decreases from subequatorial to temperate zone.
3. mediterranean type - maximum precipitation in winter, minimum - in summer. It is observed in subtropical latitudes on the western coasts and inland. 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 total 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.