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What is atmospheric precipitation, what types. Precipitation. What is precipitation? What types of precipitation do you know

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 the air layer, and are also associated with the transition of water dispersion to various states of aggregation and precipitation on 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 is based on the fact that in a certain volume of air there can be 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 temperatures, 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 is 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. This is mainly due to the very low relative humidity of the 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 are applied), 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. The decrease in 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 geographic zones. Conditional division is carried out depending on seasonality, however, it should be remembered that combinations can occur in the off-season. Precipitation is also the most important element of water circulation on the planet.

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.

According to aggregate state 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 of daily precipitation patterns - 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 is different at 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 of the Pacific Ocean, precipitation is 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. In 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.

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 air masses with different temperatures and other physical properties meet, fall out of warmer air that forms cyclonic eddies, are typical of the 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 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. 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. 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. 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, 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.

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 clouds, merge 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 surface 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 is rainfall, it is torrential. 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 of various shapes. 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 of a hen's egg, usually with varying layers of 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.

What is water vapor? What properties does it have?

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

What seasons of the year does it rain in your area? What are the snowfalls?

Rains fall in summer, autumn, spring. Snowfalls - winter, late autumn, early spring.

Compare the average annual rainfall in Algeria and Vladivostok using Figure 119. Is rainfall distributed equally over the months?

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

Look at the picture and talk about the alternation of belts with different annual rainfall.

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

Questions and tasks

1. How is precipitation formed?

Precipitation is water that falls to the ground from clouds (rain, snow, hail) or directly from the air (dew, hoarfrost, frost). Clouds are made up of tiny water droplets 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 of precipitation.

2. Name the types of precipitation.

Precipitation is liquid (rain), solid (snow, hail, grains) and mixed (snow with rain)

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

When it collides with cold air, warm air, displaced by 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 doesn't it always rain on cloudy days?

Precipitation occurs only when the air is saturated with moisture.

5. How can one explain that there is a lot of precipitation near the equator, and very little in the regions of the poles?

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

6. What is the annual rainfall in your area?

In the European part of Russia, about 500 mm falls on average per year.

Precipitation

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

Precipitation classification

Precipitation falling on the earth's surface

Heavy rainfall

They are characterized by monotony of precipitation without significant fluctuations in intensity. 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 or an hour. They usually fall out of nimbostratus or altostratus clouds; at the same time, 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-hour) precipitation is observed from stratus, stratocumulus, altocumulus clouds, while the number of clouds is 7-10 points. In frosty weather (air temperature below -10 ... -15 °), light snow can fall from a cloudy sky.

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

supercooled 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 falling at negative air temperature (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 - falling on objects, the balls break into shells, water flows out and ice forms.

Snow- solid precipitation falling (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 1-3 km, with heavy snow - less than 1000 m (at the same time, snowfall intensifies gradually, so that 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 can fall from a cloudy sky. Separately, the phenomenon of wet snow is noted - mixed precipitation that falls at a positive air temperature in the form of flakes of melting snow.

Rain with snow- mixed precipitation falling (most often at positive air temperature) in the form of a mixture of drops and snowflakes. If rain with snow falls at a negative air temperature, particles of precipitation freeze on objects and ice forms.

Drizzling precipitation

They are characterized by low intensity, monotony of precipitation without a change in intensity; start and stop gradually. The duration of continuous precipitation is usually several hours (and sometimes 1-2 days). Fall out of stratus clouds or fog; at the same time, 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 a deterioration in 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 gets wet slowly and evenly. Settling on the surface of the water does not form diverging circles on it.

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

heavy rainfall

They are characterized by the suddenness of the beginning and end of the fallout, a sharp change in intensity. The duration of continuous fallout is usually 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 out of cumulonimbus clouds, while 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 sign of rain showers is not their high intensity (rain showers can be weak), but the very fact of falling out of convective (most often cumulonimbus) clouds, which determines the fluctuations in precipitation intensity. In hot weather, light showers can fall from powerful cumulus, and sometimes (very light showers) even from medium cumulus.

torrential rain- torrential rain.

shower snow- heavy 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").

Heavy rain with snow- Mixed precipitation of a shower character, falling out (most often at positive air temperature) in the form of a mixture of drops and snowflakes. If heavy rain with snow falls at a negative air temperature, particles of precipitation freeze on objects and ice forms.

snow grits- solid precipitation of a shower character, falling out at an air temperature of about zero ° and having the form of opaque white grains with a diameter of 2-5 mm; grains are fragile, easily crushed by fingers. It often falls before or at the same time as heavy snow.

ice grits- solid precipitation of a shower character, falling out at an air temperature of -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 is an opaque core. The grains are quite hard (they are crushed with fingers with some effort), and when they fall on a hard surface, they bounce off. In some cases, the grains can be covered with a water film (or fall out together with water droplets), 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 an air temperature 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 panes, etc.). The duration of the hail is usually small - from 1-2 to 10-20 minutes. In most cases, hail is accompanied by heavy rain 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 rays of the sun, at night - in the rays of the moon or in the light of lanterns. Quite often, ice needles form beautiful luminous "pillars" at night, going from the lanterns up into the sky. They are observed most often in clear or slightly cloudy skies, sometimes they fall out of cirrostratus or cirrus clouds.

Isolation- precipitation in the form of rare and large (up to 3 cm) water bubbles. A rare occurrence 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 the condensation of water vapor contained in the air at positive air and soil temperatures, cloudy skies and light winds. Most often observed at night and early morning hours, may be accompanied by haze or fog. Abundant dew can cause measurable precipitation (up to 0.5 mm per night), runoff of water from roofs to the ground.

Frost- a white crystalline precipitate that forms 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, cloudy skies and light winds. It is observed in the evening, night and morning hours, may be accompanied by haze or fog. In fact, this is an analogue of dew, formed at a negative temperature. On branches of trees, wires, frost is deposited weakly (unlike frost) - on the wire of an icing machine (diameter 5 mm), the thickness of frost deposition does not exceed 3 mm.

Crystal frost- a white crystalline precipitate, 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 slightly cloudy (clear, or clouds of the upper and middle tiers, or broken-stratified) frosty weather (air temperature is below -10 ... -15 °), with haze or fog (and sometimes without them) with light wind or calm. Hoarfrost usually occurs within a few hours at night, during the day it gradually crumbles under the influence of sunlight, but in cloudy weather and in shade it can persist throughout the day. On the surface of objects, roofs of buildings and cars, frost is deposited very weakly (unlike hoarfrost). 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 the fog droplets become larger, it can turn into ice, and when the air temperature drops, combined with a weakening of the wind and a decrease in the amount of cloudiness at night, it can turn into crystalline frost. The growth of granular frost lasts as long as the fog and wind last (usually several hours, and sometimes several days). Preservation of the deposited granular hoarfrost can last several days.

ice- a layer of dense vitreous ice (smooth or slightly bumpy) formed on plants, wires, objects, the earth's surface as a result of freezing of precipitation particles (supercooled drizzle, supercooled 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 a sharp 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, vehicles, can lead to wire breaks and breaking of tree branches (and sometimes to a massive fall of trees and power line masts). The growth of ice continues as long as supercooled precipitation lasts (usually several hours, and sometimes with drizzle and fog - several days). Preservation of the deposited ice can last several days.

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

Links

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