The causes of precipitation are geography. Atmospheric precipitation and its types

What is water vapor? What properties does it have?

Water vapor is the gaseous state of water. It has no color, taste or smell. Contained in the troposphere. Formed by water molecules during its evaporation. When water vapor cools, it turns into water droplets.

In what seasons of the year does it rain in your area? When does it snow?

Rain falls in summer, autumn, and spring. Snowfalls - winter, late autumn, early spring.

Using Figure 119, compare the average annual precipitation in Algeria and Vladivostok. Is precipitation distributed equally across months?

The annual precipitation in Algeria and Vladivostok is almost the same - 712 and 685 mm, respectively. However, their distribution throughout the year differs. In Algeria, maximum precipitation occurs in late autumn and winter. Minimum - at summer months. In Vladivostok, most of the precipitation falls in summer and early autumn, with the minimum falling in winter.

Look at the picture and tell us about the alternation of belts with different annual precipitation amounts.

The distribution of precipitation generally shows changes in the direction from the equator to the poles. They fall in a wide strip along the equator greatest number- over 2000 mm per year. In tropical latitudes there is very little precipitation - an average of 250-300 mm, and in temperate latitudes there are more of them again. With further approach to the poles, the amount of precipitation again decreases to 250 mm per year or less.

Questions and tasks

1. How are precipitation formed?

Atmospheric precipitation- this is water that has fallen to the ground from clouds (rain, snow, hail) or directly from the air (dew, frost, frost). Clouds are made up of tiny droplets of water and ice crystals. They are so small that they are held by air currents and do not fall to the ground. But droplets and snowflakes can merge with each other. Then they increase in size, become heavy and fall to the ground in the form atmospheric precipitation.

2. Name the types of precipitation.

Precipitation can be liquid (rain), solid (snow, hail, pellets) and mixed (snow and rain)

3. Why does the collision of warm and cold air lead to precipitation?

When it collides with cold air, the warm air, displaced by the heavy cold air, rises and begins to cool. Water vapor in warm air condenses. This leads to the formation of clouds and precipitation.

4. Why does precipitation not always fall in cloudy weather?

Precipitation only occurs if the air is oversaturated with moisture.

5. How can you explain that there is a lot of precipitation near the equator, but very little near the poles?

Large quantity precipitation falls near the equator, because due to high temperatures A large amount of moisture evaporates. The air quickly becomes saturated and precipitation occurs. At the poles, low air temperatures prevent evaporation.

6. How much precipitation falls per year in your area?

In the European part of Russia, an average of about 500 mm will fall per year.

Water molecules continuously evaporate from the surface of lakes, seas, rivers and oceans - enter the atmosphere, where they are converted into water vapor, and then into various types of precipitation. There is always water vapor in the air, which is usually impossible to see, but the humidity of the air depends on the amount of it.

Air humidity varies in all regions of the globe; in hot weather it increases when evaporation from the surface of reservoirs into the atmosphere increases. Low humidity is usually found over desert areas because there is little water vapor, so the air in deserts is very dry.

Water vapor goes through many tests before falling to the ground in the form of rain, snow or frost.

The surface of the earth is heated by the sun's rays, and the resulting heat is transferred to the air. Since heated air masses much lighter than cold ones, they rise. Tiny water droplets that formed in the air continue to travel along with it into in the form of precipitation.

Types of precipitation, fog and clouds.

To imagine how further transformation of water vapor occurs in the atmosphere, you can conduct a fairly simple experiment. You need to take a mirror and bring it closer to the spout of a boiling kettle. After a few seconds, the cool surface of the mirror will fog up, then large water drops will form on it. The released steam turned into water, which means that a phenomenon called condensation occurred.

A similar phenomenon occurs with water vapor at a distance of 2-3 km from the earth. Since the air at this distance is colder than near the surface of the earth, steam condenses in it and water droplets are formed, which can be observed from the ground in the form of clouds.

When flying on an airplane, you can see how clouds sometimes appear below the aircraft. Or you can even find yourself among the clouds if you climb high mountain in low clouds. At this moment, surrounding objects and people will turn into invisible people, swallowed up by a thick veil of fog. Fog represents the same clouds, but only located nearby earth's surface.

If the drops in the clouds begin to grow and become heavier, then the snow-white clouds gradually darken and turn into clouds. When heavy drops are no longer able to stay in the air, then rain pours from thunderclouds onto the ground. in the form of precipitation.

Dew and frost as types of precipitation.

Near bodies of water in summer, a lot of steam forms in the air and it becomes highly saturated with water pores. With the onset of night, coolness comes and at this time less steam is required to saturate the air. Excess moisture condenses on the ground, leaves, grass and other objects, and such type of precipitation called dew. Dew can be observed in the early morning, when transparent small drops are visible covering various objects.

With the arrival late autumn the temperature overnight can drop below 0°C, then the dew drops freeze and turn into amazing transparent crystals called frost.

In winter, ice crystals freeze and settle on window glass in the form of frosty patterns of extraordinary beauty. Sometimes frost simply covers the surface of the earth, like a thin layer of snow. The fantastic patterns formed by frost are best seen on rough surfaces, such as:

tree branches;
loose ground surface;
wooden benches.

Snow and hail as types of precipitation.

Pieces of ice are called hail irregular shape, which fall to the ground with rain in summer. There is also “dry” hail, which falls without rain. If you carefully cut a hailstone, you will see on the cut that it consists of alternating opaque and transparent layers.

When air currents carry water vapor to a height of about 5 km, then droplets of water begin to settle on the dust particles, and they instantly freeze. The resulting ice crystals begin to increase in size, and when they reach heavy weight I'm starting to fall. But a new stream of warm air emanates from the ground and it returns them back to the cold cloud. The hailstones begin to grow again and try to fall, this process is repeated several times, and as soon as they gain a sufficiently heavy weight they fall to the ground.

The size of these types of precipitation(hailstones) usually range from 1 to 5 mm in diameter. Although there have been cases when the size of hailstones exceeded a chicken egg, and the weight reached approximately 400-800 g.

Hail can cause great damage to agriculture; it damages vegetable gardens and crops, and also leads to the death of small animals. Large hailstones can damage cars and even pierce aircraft skins.

To reduce the likelihood of hail falling on the ground, scientists are constantly developing new substances that, using special rockets, are thrown into thunderclouds and thus disperse them.

With the arrival of winter, the earth is enveloped in a snow-white blanket consisting of tiny ice crystals called snow. Due to low temperatures, water droplets freeze and ice crystals form in the clouds, then new water molecules attach to them and, as a result, a separate snowflake is born. All snowflakes have six corners, but the patterns woven on them by frost differ from each other. When snowflakes are exposed to wind currents, they stick together and form snow flakes. Walking through the snow in frosty weather, we often hear crunching noises under our feet, as ice crystals break in the snowflakes.

Such types of precipitation, as snow brings many problems, traffic on roads becomes difficult due to snow, power lines break under its weight, and melting snow leads to floods. But thanks to the fact that the plants are covered blanket of snow, they are able to withstand even severe frosts.

Atmospheric precipitation is usually understood as water falling from the atmosphere to the surface of the earth. They are measured in millimeters. For measurements, special instruments are used - precipitation gauges or weather radars, which allow measuring different types precipitation over a large area.

On average, the planet receives about a thousand millimeters of precipitation per year. All of them are not evenly distributed across the Earth. The exact level depends on the weather, terrain, climate zone, proximity of water bodies and other indicators.

What types of precipitation are there?

From the atmosphere, water reaches the surface of the earth in two states: liquid and solid. Because of this feature, all types of precipitation are divided into:

Liquid. These include rain and dew.
Solids are snow, hail, frost.

There is a classification of precipitation types according to their shape. This is how rain is released in drops of 0.5 mm or more. Anything less than 0.5 mm is considered drizzle. Snow is ice crystals with six corners, but round solid sediments are graupel. It consists of round-shaped kernels of different diameters, which are easily compressed in the hand. Most often, such precipitation occurs at temperatures close to zero.

Hail and ice pellets are of great interest to scientists. These two types of sediment are difficult to crush with your fingers. The grain has an icy surface; when it falls, it hits the ground and bounces off. Hail is large ice that can reach eight centimeters or more in diameter. This type of precipitation usually forms in cumulonimbus clouds.

Other types

The finest type of precipitation is dew. These are tiny droplets of water that form during the process of condensation on the soil surface. When they come together, you can see dew on various objects. Favorable conditions for its formation are clear nights, when cooling of ground objects occurs. And the higher the thermal conductivity of an object, the more dew forms on it. If the temperature environment falls below zero, a thin layer of ice crystals or frost appears.

In weather forecasting, precipitation most often refers to rain and snow. However, not only these types are included in the concept of precipitation. This also includes liquid plaque, which forms in the form of drops of water or in the form of a continuous film of water in cloudy, windy weather. This type of precipitation is observed on the vertical surface of cold objects. At sub-zero temperatures, the coating becomes hard, and thin ice is most often observed.

The loose white sediment that forms on wires, ships, and more is called rime. This phenomenon is observed in foggy frosty weather with low winds. Frost can quickly build up, breaking wires and light ship equipment.

Freezing rain is another one unusual look. It occurs at subzero temperatures, most often from -10 to -15 degrees. This type has some peculiarity: the drops look like balls, covered with ice on the outside. When they fall, their shell breaks and the water inside splashes out. Under the influence of negative temperatures, it freezes, forming ice.

Precipitation is also classified according to other criteria. They are divided by the nature of the loss, by origin and more.

Character of loss

According to this qualification, all precipitation is divided into drizzle, shower, and heavy precipitation. The latter are intense, uniform rains that can fall for a long time- a day or more. This phenomenon covers quite large areas.

Drizzle falls over small areas and consists of small drops of water. Rainfall refers to rainfall. It is intense, does not last long, and covers a small area.

Origin

Based on their origin, precipitation is divided into frontal, orographic and convective precipitation.

Orographic fall out on mountain slopes. They flow most abundantly if warm air with relative humidity comes from the sea.

The convective type is characteristic of the hot zone, where heating and evaporation occur with high intensity. The same species is found in the temperate zone.

Frontal precipitation is formed when air masses meet with different temperatures. This type of them is concentrated in cold, temperate climate.

Quantity

Meteorologists long time observe precipitation, its amount, pointing to climate maps their intensity. So, if you look at annual maps, you can trace the unevenness of precipitation around the world. The rains are most intense in the area of the Amazon River, but in the Sahara Desert there is little rainfall.

The unevenness is explained by the fact that precipitation is brought by moist air masses that form over the oceans. This is most clearly visible in the area with monsoon climate. Most moisture comes into summer time with the monsoons. There are long periods of rain over land, such as on the Pacific coast of Europe.

Winds play a significant role. Blowing from the continent, they carry dry air to northern territories Africa, home to the world's largest desert. And winds bring rain from the Atlantic to European countries.

Precipitation in the form of showers is influenced by sea currents. Warm promotes their appearance, while cold, on the contrary, prevents them.

The terrain plays an important role. The Himalayan mountains do not allow moist winds from the ocean to pass to the north, which is why up to 20 thousand millimeters of precipitation falls on their slopes, but on the other hand, there is practically none.

Scientists have found that there is a relationship between atmospheric pressure and amount of precipitation. On the territory of the equator in the belt low pressure The air is constantly heated, it forms clouds and heavy rains. Large amounts of precipitation also occur in other areas of the Earth. However, where low temperature air, precipitation does not often occur in the form freezing rain and snow.

Fixed data

Scientists continually record rainfall across the globe. The most precipitation recorded was on Hawaiian Islands located in Pacific Ocean, in India. Over 11,000 millimeters fell in these areas during the year. The minimum was recorded in the Libyan Desert and Atakami - less than 45 millimeters per year, sometimes in these areas there is no precipitation at all for several years.

Atmospheric precipitation

Long-term, average monthly, seasonal, annual precipitation, its distribution over the earth's surface, annual and daily variations, frequency, intensity are the defining characteristics of climate that are essential for agriculture and many other sectors of the national economy.

Classification of precipitation

Precipitation falling on the earth's surface

Cover precipitation

They are characterized by monotony of loss without significant fluctuations in intensity. They start and stop gradually. The duration of continuous precipitation is usually several hours (and sometimes 1-2 days), but in some cases light precipitation can last half an hour to an hour. Usually fall from nimbostratus or altostratus clouds; Moreover, in most cases the cloudiness is continuous (10 points) and only occasionally significant (7-9 points, usually at the beginning or end of the precipitation period). Sometimes weak short-term (half an hour to an hour) precipitation is observed from stratus, stratocumulus, altocumulus clouds, with the number of clouds being 7-10 points. In frosty weather (air temperature below −10...-15°), light snow may fall from a partly cloudy sky.

Rain- liquid precipitation in the form of droplets with a diameter of 0.5 to 5 mm. Individual raindrops leave a mark on the surface of water in the form of a diverging circle, and on the surface of dry objects - in the form of a wet spot.

Freezing rain- liquid precipitation in the form of drops with a diameter of 0.5 to 5 mm, falling at negative air temperatures (most often 0...-10°, sometimes up to −15°) - falling on objects, the drops freeze and ice forms.

freezing rain- solid precipitation that falls at negative air temperatures (most often 0...-10°, sometimes up to −15°) in the form of solid transparent ice balls with a diameter of 1-3 mm. There is unfrozen water inside the balls - when falling on objects, the balls break into shells, the water flows out and ice forms.

Snow- solid precipitation that falls (most often at negative air temperatures) in the form of snow crystals (snowflakes) or flakes. With light snow, horizontal visibility (if there are no other phenomena - haze, fog, etc.) is 4-10 km, with moderate snow 1-3 km, with heavy snow - less than 1000 m (in this case, snowfall increases gradually, so Visibility values of 1-2 km or less are observed no earlier than an hour after the start of snowfall). In frosty weather (air temperature below −10...-15°), light snow may fall from a partly cloudy sky. Separately, the phenomenon of wet snow is noted - mixed precipitation, falling at positive air temperatures in the form of flakes of melting snow.

Sleet- mixed precipitation that falls (most often at positive air temperatures) in the form of a mixture of drops and snowflakes. If rain and snow fall at subzero air temperatures, precipitation particles freeze onto objects and ice forms.

Drizzle

Characterized by low intensity, monotonous loss without changing intensity; start and stop gradually. The duration of continuous loss is usually several hours (and sometimes 1-2 days). Fall out of stratus clouds or fog; Moreover, in most cases the cloudiness is continuous (10 points) and only occasionally significant (7-9 points, usually at the beginning or end of the precipitation period). Often accompanied by decreased visibility (haze, fog).

Drizzle- liquid precipitation in the form of very small drops (less than 0.5 mm in diameter), as if floating in the air. A dry surface becomes wet slowly and evenly. When deposited on the surface of the water, it does not form diverging circles on it.

Freezing drizzle- liquid precipitation in the form of very small drops (less than 0.5 mm in diameter), as if floating in the air, falling at negative air temperatures (most often 0...-10°, sometimes up to −15°) - settling on objects, the drops freeze and ice forms.

Snow grains- solid precipitation in the form of small opaque white particles (sticks, grains, grains) with a diameter of less than 2 mm, falling at negative air temperatures.

Rainfall

They are characterized by the suddenness of the beginning and end of the loss, and a sharp change in intensity. The duration of continuous loss usually ranges from several minutes to 1-2 hours (sometimes several hours, in the tropics - up to 1-2 days). Often accompanied by a thunderstorm and a short-term increase in wind (squall). They fall from cumulonimbus clouds, and the amount of clouds can be both significant (7-10 points) and small (4-6 points, and in some cases even 2-3 points). The main feature of rainfall precipitation is not its high intensity (rainfall can be weak), but the very fact of precipitation from convective (most often cumulonimbus) clouds, which determines fluctuations in precipitation intensity. IN hot weather light showers can fall from powerful cumulus clouds, and sometimes (very light showers) even from mid cumulus clouds.

Rain shower- torrential rain.

Shower snow- shower snow. It is characterized by sharp fluctuations in horizontal visibility from 6-10 km to 2-4 km (and sometimes up to 500-1000 m, in some cases even 100-200 m) over a period of time from several minutes to half an hour (snow “charges”).

Shower rain with snow- mixed rainfall precipitation, falling (most often at positive air temperatures) in the form of a mixture of drops and snowflakes. If heavy rain with snow falls at sub-zero air temperatures, precipitation particles freeze onto objects and ice forms.

Snow pellets- solid rainfall precipitation that falls at an air temperature of about zero degrees and has the appearance of opaque white grains with a diameter of 2-5 mm; The grains are fragile and easily crushed by fingers. Often falls before or simultaneously with heavy snow.

Ice grains- solid rainfall precipitation that falls at air temperatures from −5 to +10° in the form of transparent (or translucent) ice grains with a diameter of 1-3 mm; in the center of the grains there is an opaque core. The grains are quite hard (they can be crushed with your fingers with some effort), and when they fall on a hard surface they bounce off. In some cases, grains may be covered with a film of water (or fall out along with droplets of water), and if the air temperature is below zero, then falling on objects, the grains freeze and ice forms.

hail- solid precipitation that falls in the warm season (at air temperatures above +10°) in the form of pieces of ice various shapes and sizes: usually the diameter of hailstones is 2-5 mm, but in some cases individual hailstones reach the size of a pigeon and even chicken egg(then hail causes significant damage to vegetation, car surfaces, breaks window glass, etc.). The duration of hail is usually short - from 1-2 to 10-20 minutes. In most cases, hail is accompanied by rain showers and thunderstorms.

Unclassified precipitation

Ice needles- solid precipitation in the form of tiny ice crystals floating in the air, formed in frosty weather (air temperature below −10…-15°). During the day they sparkle in the light of the sun's rays, at night - in the rays of the moon or in the light of lanterns. Quite often, ice needles form beautiful glowing “pillars” at night, extending from the lanterns upward into the sky. They are most often observed in clear or partly cloudy skies, sometimes falling from cirrostratus or cirrus clouds.

Insulation- precipitation in the form of rare and large (up to 3 cm) water bubbles. A rare phenomenon that occurs during light thunderstorms.

Precipitation formed on the surface of the earth and on objects

Dew- water droplets formed on the surface of the earth, plants, objects, roofs of buildings and cars as a result of condensation of water vapor contained in the air at positive air and soil temperatures, partly cloudy skies and weak winds. Most often observed at night and early morning hours, and may be accompanied by haze or fog. Heavy dew can cause measurable amounts of precipitation (up to 0.5 mm per night), running off water from roofs onto the ground.

Frost- a white crystalline sediment formed on the surface of the earth, grass, objects, roofs of buildings and cars, snow cover as a result of desublimation of water vapor contained in the air at negative soil temperatures, partly cloudy skies and weak winds. It is observed in the evening, night and morning hours, and may be accompanied by haze or fog. In fact, it is an analogue of dew, formed at negative temperatures. On tree branches and wires, frost is deposited weakly (unlike frost) - on the wire of an ice machine (diameter 5 mm), the thickness of frost deposits does not exceed 3 mm.

Crystal frost- a white crystalline sediment consisting of small, fine-structured shiny particles of ice, formed as a result of desublimation of water vapor contained in the air on tree branches and wires in the form of fluffy garlands (easily crumbling when shaken). It is observed in lightly cloudy (clear, or clouds of the upper and middle tier, or broken-stratified) frosty weather (air temperature below −10 ... -15 °), with haze or fog (and sometimes without them) with weak wind or calm. Frost deposition occurs, as a rule, within several hours at night; during the day it gradually crumbles under the influence of sun rays, however, in cloudy weather and in the shade it can persist throughout the day. On the surface of objects, roofs of buildings and cars, frost is deposited very weakly (unlike frost). However, frost is often accompanied by frost.

Grainy frost- white loose snow-like sediment formed as a result of the settling of small droplets of supercooled fog on tree branches and wires in cloudy, foggy weather (at any time of the day) at air temperatures from zero to −10° and moderate or strong wind. When fog droplets become larger, it can turn into ice, and when the air temperature drops in combination with weakening winds and a decrease in the amount of clouds at night, it can turn into crystalline frost. The growth of grainy frost continues as long as the fog and wind last (usually several hours, and sometimes several days). The deposited granular frost may persist for several days.

Ice- a layer of dense glassy ice (smooth or slightly lumpy), formed on plants, wires, objects, the surface of the earth as a result of the freezing of precipitation particles (supercooled drizzle, freezing rain, freezing rain, ice pellets, sometimes rain with snow) in contact with the surface, having negative temperature. It is observed at air temperatures most often from zero to −10° (sometimes up to −15°), and during sudden warming (when the earth and objects still maintain a negative temperature) - at an air temperature of 0…+3°. It greatly complicates the movement of people, animals, and vehicles, and can lead to broken wires and breaking off tree branches (and sometimes to massive falls of trees and power line masts). The growth of ice continues as long as the supercooled precipitation lasts (usually several hours, and sometimes with drizzle and fog - several days). The deposited ice may persist for several days.

Black ice- a layer of lumpy ice or icy snow formed on the surface of the earth due to the freezing of melt water when, after a thaw, the temperature of the air and soil decreases (transition to negative values temperature). Unlike ice, black ice is observed only on the earth's surface, most often on roads, sidewalks and paths. The resulting ice can persist for many days in a row until it is covered with freshly fallen snow or melts completely as a result of an intense increase in air and soil temperatures.

Links

// Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional ones). - St. Petersburg. , 1890-1907.

Atmospheric precipitation Atmospheric precipitation is water in a droplet-liquid (rain, drizzle) and solid (snow, pellets, hail) state, falling from clouds or depositing directly from the air onto the surface of the Earth and objects (dew, drizzle, frost, ice) as a result of condensation of water vapor, in the air.

Atmospheric precipitation is also the amount of water that falls in certain place over a certain period of time (usually measured by the thickness of the layer of fallen water in mm). The amount of precipitation depends on air temperature, atmospheric circulation, relief, and sea currents.

There are continuous precipitation associated mainly with warm fronts, and rainfall associated with cold fronts. Precipitation deposited from the air: dew, frost, frost, ice.

Precipitation is measured by the thickness of the layer of fallen water in millimeters. On average per globe falls out approx. 1000 mm of precipitation per year: from 2500 mm in humid equatorial forests up to 10 mm in deserts and 250 mm in high latitudes. Precipitation measurements are carried out using rain gauges, precipitation gauges, pluviographs on weather stations, and for large areas- using radar.

Classification of precipitation

Precipitation falling on the earth's surface

Cover precipitation- characterized by monotony of loss without significant fluctuations in intensity. They start and stop gradually. The duration of continuous precipitation is usually several hours (and sometimes 1-2 days), but in some cases light precipitation can last half an hour to an hour. Usually fall from nimbostratus or altostratus clouds; Moreover, in most cases the cloudiness is continuous (10 points) and only occasionally significant (7-9 points, usually at the beginning or end of the precipitation period). Sometimes weak short-term (half an hour to an hour) precipitation is observed from stratus, stratocumulus, altocumulus clouds, with the number of clouds being 7-10 points. In frosty weather (air temperature below −10...-15°), light snow may fall from a partly cloudy sky.

Rain- liquid precipitation in the form of droplets with a diameter of 0.5 to 5 mm. Individual raindrops leave a mark on the surface of water in the form of a diverging circle, and on the surface of dry objects - in the form of a wet spot.

Freezing rain- liquid precipitation in the form of drops with a diameter of 0.5 to 5 mm, falling at negative air temperatures (most often 0...-10°, sometimes up to −15°) - falling on objects, the drops freeze and ice forms.

freezing rain- solid precipitation that falls at negative air temperatures (most often 0...-10°, sometimes up to −15°) in the form of solid transparent ice balls with a diameter of 1-3 mm. There is unfrozen water inside the balls - when falling on objects, the balls break into shells, the water flows out and ice forms.

Snow- solid precipitation that falls (most often at negative air temperatures) in the form of snow crystals (snowflakes) or flakes. With light snow, horizontal visibility (if there are no other phenomena - haze, fog, etc.) is 4-10 km, with moderate snow 1-3 km, with heavy snow - less than 1000 m (in this case, snowfall increases gradually, so Visibility values of 1-2 km or less are observed no earlier than an hour after the start of snowfall). In frosty weather (air temperature below −10...-15°), light snow may fall from a partly cloudy sky. Separately, the phenomenon of wet snow is noted - mixed precipitation that falls at positive air temperatures in the form of flakes of melting snow.

Sleet- mixed precipitation that falls (most often at positive air temperatures) in the form of a mixture of drops and snowflakes. If rain and snow fall at subzero air temperatures, precipitation particles freeze onto objects and ice forms.

Drizzle- characterized by low intensity, monotony of loss without changing intensity; start and stop gradually. The duration of continuous loss is usually several hours (and sometimes 1-2 days). Fall out of stratus clouds or fog; Moreover, in most cases the cloudiness is continuous (10 points) and only occasionally significant (7-9 points, usually at the beginning or end of the precipitation period). Often accompanied by decreased visibility (haze, fog).

Drizzle- liquid precipitation in the form of very small drops (less than 0.5 mm in diameter), as if floating in the air. A dry surface becomes wet slowly and evenly. When deposited on the surface of the water, it does not form diverging circles on it.

Freezing drizzle- liquid precipitation in the form of very small drops (with a diameter of less than 0.5 mm), as if floating in the air, falling at negative air temperatures (most often 0 ... -10 °, sometimes up to −15 °) - settling on objects, the drops freeze and form ice

Snow grains- solid precipitation in the form of small opaque white particles (sticks, grains, grains) with a diameter of less than 2 mm, falling at negative air temperatures.

Rainfall- characterized by the suddenness of the beginning and end of the loss, a sharp change in intensity. The duration of continuous loss usually ranges from several minutes to 1-2 hours (sometimes several hours, in the tropics - up to 1-2 days). Often accompanied by a thunderstorm and a short-term increase in wind (squall). They fall from cumulonimbus clouds, and the amount of clouds can be both significant (7-10 points) and small (4-6 points, and in some cases even 2-3 points). The main feature of rainfall precipitation is not its high intensity (rainfall can be weak), but the very fact of precipitation from convective (most often cumulonimbus) clouds, which determines fluctuations in precipitation intensity. In hot weather, light showers can fall from powerful cumulus clouds, and sometimes (very light showers) even from mid-cumulus clouds.

shower rain- torrential rain.

Shower snow- shower snow. It is characterized by sharp fluctuations in horizontal visibility from 6-10 km to 2-4 km (and sometimes up to 500-1000 m, in some cases even 100-200 m) over a period of time from several minutes to half an hour (snow “charges”).

Shower rain with snow- mixed rainfall precipitation, falling (most often at positive air temperatures) in the form of a mixture of drops and snowflakes. If heavy rain with snow falls at sub-zero air temperatures, precipitation particles freeze onto objects and ice forms.

Snow pellets- solid precipitation of a storm nature, falling at an air temperature of about zero degrees and having the appearance of opaque white grains with a diameter of 2-5 mm; The grains are fragile and easily crushed by fingers. Often falls before or simultaneously with heavy snow.

Ice grains- solid rainfall precipitation, falling at air temperatures from −5 to +10° in the form of transparent (or translucent) ice grains with a diameter of 1-3 mm; in the center of the grains there is an opaque core. The grains are quite hard (they can be crushed with your fingers with some effort), and when they fall on a hard surface they bounce off. In some cases, grains may be covered with a film of water (or fall out along with droplets of water), and if the air temperature is below zero, then falling on objects, the grains freeze and ice forms.

hail- solid precipitation that falls in the warm season (at air temperatures above +10°) in the form of pieces of ice of various shapes and sizes: usually the diameter of hailstones is 2-5 mm, but in some cases individual hailstones reach the size of a pigeon and even a chicken egg ( then hail causes significant damage to vegetation, car surfaces, breaks window glass, etc.). The duration of hail is usually short - from 1-2 to 10-20 minutes. In most cases, hail is accompanied by rain showers and thunderstorms.

Unclassified precipitation

Ice needles- solid precipitation in the form of tiny ice crystals floating in the air, formed in frosty weather (air temperature below −10…-15°). During the day they sparkle in the light of the sun's rays, at night - in the rays of the moon or in the light of lanterns. Quite often, ice needles form beautiful glowing “pillars” at night, extending from the lanterns upward into the sky. They are most often observed in clear or partly cloudy skies, sometimes falling from cirrostratus or cirrus clouds. Ice needles

Precipitation formed on the surface of the earth and on the surface metax

Dew- water droplets formed on the surface of the earth, plants, objects, roofs of buildings and cars as a result of condensation of water vapor contained in the air at positive air and soil temperatures, partly cloudy skies and weak winds. Most often observed at night and early morning hours, and may be accompanied by haze or fog. Heavy dew can cause measurable amounts of precipitation (up to 0.5 mm per night), draining water from roofs onto the ground.

Frost- a white crystalline sediment formed on the surface of the earth, grass, objects, roofs of buildings and cars, snow cover as a result of sublimation of water vapor contained in the air at negative soil temperatures, partly cloudy skies and weak winds. It is observed in the evening, night and morning hours, and may be accompanied by haze or fog. In fact, it is an analogue of dew, formed at negative temperatures. On tree branches and wires, frost is deposited weakly (unlike frost) - on the wire of an ice machine (diameter 5 mm), the thickness of frost deposits does not exceed 3 mm.

Crystal frost- a white crystalline sediment consisting of small, fine-structured shiny particles of ice, formed as a result of sublimation of water vapor contained in the air on tree branches and wires in the form of fluffy garlands (easily crumbling when shaken). It is observed in lightly cloudy (clear, or clouds of the upper and middle tier, or broken-stratified) frosty weather (air temperature below −10...-15°), with haze or fog (and sometimes without them) with weak wind or calm. Frost deposits usually occur over several hours at night; during the day, it gradually crumbles under the influence of sunlight, but in cloudy weather and in the shade it can persist throughout the day. On the surface of objects, roofs of buildings and cars, frost is deposited very weakly (unlike frost). However, frost is often accompanied by frost.

Grainy frost- white loose snow-like sediment formed as a result of the settling of small droplets of supercooled fog on tree branches and wires in cloudy, foggy weather (at any time of the day) at air temperatures from zero to −10° and moderate or strong wind. When fog droplets become larger, it can turn into ice, and when the air temperature drops in combination with weakening winds and a decrease in the amount of clouds at night, it can turn into crystalline frost. The growth of grainy frost continues as long as the fog and wind last (usually several hours, and sometimes several days). The deposited granular frost may persist for several days.

Ice- a layer of dense glassy ice (smooth or slightly lumpy), formed on plants, wires, objects, the surface of the earth as a result of the freezing of precipitation particles (supercooled drizzle, freezing rain, freezing rain, ice pellets, sometimes rain with snow) in contact with the surface, having a negative temperature. It is observed at air temperatures most often from zero to −10° (sometimes up to −15°), and during sudden warming (when the earth and objects still maintain a negative temperature) - at an air temperature of 0…+3°. It greatly impedes the movement of people, animals, and vehicles, and can lead to broken wires and breaking off tree branches (and sometimes to massive falls of trees and power line masts). The growth of ice continues as long as the supercooled precipitation lasts (usually several hours, and sometimes with drizzle and fog - several days). The deposited ice may persist for several days.

Black ice- a layer of lumpy ice or icy snow formed on the surface of the earth due to the freezing of melt water when, after a thaw, the temperature of the air and soil decreases (transition to negative temperature values). Unlike ice, black ice is observed only on the earth's surface, most often on roads, sidewalks and paths. The resulting ice can persist for many days in a row until it is covered with freshly fallen snow or melts completely as a result of an intense increase in air and soil temperatures.