Solid precipitation. Definition and types

Precipitation

Long-term, average monthly, seasonal, annual amount 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 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 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 falling in the warm season (at air temperatures above +10 °) in the form of pieces of ice various shapes and size: 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 a surface that has 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 hilly ice or icy snow, formed on the surface of the earth due to freezing of melt water, when, after a thaw, the temperature of air and soil decreases (transition to negative values temperature). 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.

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 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 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.

Water that falls on the Earth's surface in the form of rain, snow, hail or condensed on objects as frost or dew is called precipitation. Precipitation can be heavy rainfall associated with warm fronts or showers associated with cold fronts.

The appearance of rain is due to the merging of small droplets of water in a cloud into larger ones, which, overcoming gravity, fall to the Earth. In the event that the cloud contains small particles of solids (dust particles), the condensation process proceeds faster, since they act as condensation nuclei. At negative temperatures, the condensation of water vapor in the cloud leads to snowfall. If snowflakes from the upper layers of the cloud fall into the lower ones with a higher temperature, where a large number of cold drops of water, then the snowflakes are combined with water, losing their shape and turning into snowballs up to 3 mm in diameter.

Precipitation formation

Hail is formed in clouds of vertical development, characteristic features which is the presence of positive temperatures in the lower layer and negative - in the upper. In this case, spherical snowballs with ascending air currents rise to the upper parts of the cloud with lower temperatures and freeze with the formation of spherical ice - hailstones. Then, under the influence of gravity, the hailstones fall to the Earth. They usually vary in size and can be as small as a pea to a chicken egg.

Types of precipitation

Such types of precipitation as dew, hoarfrost, hoarfrost, ice, fog, are formed in the surface layers of the atmosphere due to the condensation of water vapor on objects. Dew appears at more high temperatures, frost and frost - with negative. At excessive concentration water vapor in the surface atmospheric layer, fog appears. If fog mixes with dust and dirt in industrial cities, it is called smog.
Precipitation is measured by the thickness of the water layer in millimeters. On our planet, on average, about 1000 mm of precipitation falls annually. A rain gauge is used to measure the amount of precipitation. For many years, observations have been made of the amount of precipitation in different regions of the planet, thanks to which the general patterns of their distribution over the earth's surface have been established.

The maximum amount of precipitation occurs in equatorial belt(up to 2000 mm per year), the minimum - in the tropics and polar regions (200-250 mm per year). In the temperate zone, the average annual rainfall is 500-600 mm per year.

In every climate zone there is also irregularity in precipitation. This is due to the peculiarities of the relief of a certain area and the prevailing wind direction. For example, on the western outskirts of the Scandinavian mountain range, 1000 mm falls per year, and on the eastern outskirts - more than two times less. Areas of land were identified, on which precipitation is almost completely absent. These are the Atacama Deserts, the central regions of the Sahara. In these regions, the average annual rainfall is less than 50 mm. A huge amount of precipitation is observed in the southern regions of the Himalayas, in Central Africa (up to 10,000 mm per year).

Thus, the determining features of the climate of a given area are the average monthly, seasonal, average annual precipitation, their distribution over the Earth's surface, and intensity. These climate features have a significant impact on many sectors of the human economy, including agriculture.

Related content:

Atmosphere

Atmosphere pressure

The value of the atmosphere

Types of precipitation

For precipitation there are different classifications.

Atmospheric precipitation and its chemical composition

A distinction is made between heavy rainfall, which is associated with warm fronts, and heavy rainfall, which is associated with cold fronts.

Precipitation is measured in millimeters - the thickness of the layer of fallen water. On average, about 250 mm per year falls in high latitudes and deserts, and on the globe as a whole, about 1000 mm of precipitation per year.

Precipitation measurement is essential for any geographical research. After all, precipitation is one of the most important links in the moisture cycle on the globe.

The determining characteristics for a particular climate are the average monthly, annual, seasonal and long-term precipitation, their daily and annual course, their frequency and intensity.

These indicators are extremely important for most sectors of the national (agricultural) economy.

Rain is a liquid precipitation - in the form of drops from 0.4 to 5-6 mm. Raindrops can leave a trace in the form of a wet spot on a dry object, on the surface of the water - in the form of a divergent circle.

Exist different types rain: icy, supercooled and rain with snow. Both supercooled rain and icy rain fall at negative air temperatures.

Supercooled rain is characterized by liquid precipitation, the diameter of which reaches 5 mm; after this type of rain, ice can form.

A freezing rain It is represented by precipitation in a solid state - these are balls of ice, inside of which there is frozen water. Snow is called precipitation, which falls in the form of flakes and snow crystals.

Horizontal visibility depends on the intensity of snowfall. Distinguish between sleet and sleet.

The concept of weather and its features

The state of the atmosphere in a particular place at a particular time is called the weather. Weather is the most variable phenomenon in environment. Sometimes it starts to rain, sometimes it starts to wind, and after a few hours the sun will shine and the wind will subside.

But even in the variability of the weather there are regularities, despite the fact that a huge number of factors influence the formation of the weather.

The main elements characterizing the weather can be called such meteorological indicators: solar radiation, Atmosphere pressure, air humidity and temperature, precipitation and wind direction, wind strength and cloud cover.

If we talk about the changeability of the weather, then most often it changes in temperate latitudes - in regions with a continental climate. And the weather is most stable in the polar and equatorial latitudes.

The change in weather is associated with the change of season, that is, the changes are periodic, and weather conditions repeat over time.

Every day we observe the daily change of the weather - the night follows the day, and for this reason the weather conditions change.

The concept of climate

The long-term weather regime is called the climate. The climate is determined in a particular area - thus, the weather regime must be stable for a certain geographical location.

In other words, climate can be called the average value of weather over a long period of time. Often this period is more than several decades.

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Heavy rainfall

Prolonged (from several hours to a day or more) atmospheric precipitation in the form of rain (common rain) or snow (common snow), falling over a large area with a fairly uniform intensity from nimbostratus and altostratus clouds on a warm front. Heavy rainfall keeps the soil moist.

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 out at negative air temperatures (most often 0 ... -10 °, sometimes up to -15 °) - falling on objects, the drops freeze and ice forms. Supercooled rain is formed when falling snowflakes hit a layer of warm air deep enough for the snowflakes to completely melt and turn into raindrops. As these droplets continue to fall, they pass through a thin layer of cold air above the earth's surface and become below freezing. However, the droplets themselves do not freeze, which is why this phenomenon is called supercooling (or the formation of "supercooled droplets").

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. Formed when raindrops freeze as they fall through a lower layer of sub-zero air. 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.

Precipitation

If rain with snow falls at a negative air temperature, particles of precipitation freeze on objects and ice forms.

Drizzling precipitation

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 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 out at negative air temperatures.

Fog- accumulation of condensation products (droplets or crystals, or both), suspended in the air, directly above the earth's surface. Cloudiness of the air caused by such accumulation. Usually these two meanings of the word mist do not differ. In fog, horizontal visibility is less than 1 km. Otherwise, haze is called haze.

heavy rainfall

Shower- short-term precipitation, usually in the form of rain (sometimes - wet snow, cereals), characterized by high intensity (up to 100 mm / h). Occur in unstable air masses on a cold front or as a result of convection. Typically, heavy rain covers a relatively small area.

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.

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.

Many factors determine how much rain or snow will fall on earth's surface. These are temperature, altitude, location of mountain ranges, etc.

Probably the rainiest place in the world is Mount Waialeale in Hawaii, on the island of Kauai. The average annual rainfall here is 1197 cm. Cherrapunji in India arguably ranks second in terms of rainfall with an average annual level of 1079 to 1143 cm. Once, 381 cm of rain fell in Cherrapunji in 5 days. And in 1861, the amount of precipitation reached 2300 cm!

To make it clearer, let's compare rainfall in some cities around the world, London gets 61 cm of rain per year, Edinburgh about 68 cm and Cardiff about 76 cm. New York gets about 101 cm of rain. Ottawa in Canada gets 86 cm, Madrid about 43 cm and Paris 55 cm. So you see what a contrast Cherrapunji is.

The driest place in the world is probably Arica in Chile. Here the rainfall is 0.05 cm per year. The driest place in the US is Greenland Ranch in Death Valley. There, the average annual rainfall is less than 3.75 cm.

In some vast regions of the Earth, heavy rainfall occurs all year round. For example, almost every point along the equator receives 152 cm or more of precipitation each year. The equator is the junction of two large streams of air. Throughout the equator, air moving down from the north meets air moving up from the south.

There is a main upward movement of hot air mixed with water vapor. As the air rises to colder altitudes, a large amount of water vapor condenses and falls as rain.

Most of the rain falls on the windward side of the mountains. The other side, called the leeward side, receives much less precipitation. An example is the Cascade Mountains in California. West winds carrying water vapor move from Pacific Ocean. Having reached the coast, the air rises along the western slopes of the mountains, cooling.

Precipitation. Scheme and types of precipitation

Cooling causes the condensation of water vapor, which falls as rain or snow.

Depending on the nature of the cloudiness and the mode of precipitation, there are two types of them. daily course: continental and marine. The continental type is characterized by two maxima: the main one - in the afternoon from convective cumulonimbus, and at the equator from cumulus clouds, and insignificant - early in the morning from stratus clouds, between them there are minima: at night and before noon.

What is precipitation? What types of precipitation do you know?

In the marine (coastal) type, there is one precipitation maximum at night (due to unstable air stratification and convection) and one minimum during the day. These types of daily precipitation patterns are observed throughout the year in the hot zone, while in the temperate zones they are possible only in summer.

The annual course of precipitation, i.e., their change by months during the year, is very different in different places on the Earth. This depends on many factors: the radiation regime, the general circulation of the atmosphere, the specific physical and geographical situation, etc. Several main types of annual precipitation can be identified and expressed in the form of bar graphs (Fig. 47).

Rice. 47. Types of the annual course of precipitation on the example of the northern hemisphere

Equatorial type - heavy precipitation falls fairly evenly throughout the year, there are no dry months, there are two small maximums - in April and October, after the days of the equinoxes, and two small minimums in July and January, after the days of the solstices.

Monsoon type - maximum precipitation in summer, minimum - in winter. It is characteristic of subequatorial latitudes, where the annual course of precipitation is very pronounced due to the dryness of winter, as well as the eastern coasts of continents in subtropical and temperate latitudes. However, the annual precipitation amplitude is somewhat smoothed here, especially in the subtropics, where frontal rains also fall in winter. The annual amount of precipitation at the same time gradually decreases from the subequatorial to the temperate zone.

Mediterranean type - maximum precipitation in winter due to active frontal activity, minimum - in summer. It is observed in subtropical latitudes on the western coasts and inland.

In temperate latitudes, two main types of annual precipitation are distinguished: continental and marine. The continental (inland) type is distinguished by the fact that two to three times more precipitation falls here in summer than in winter, due to frontal and convective precipitation.

Marine type - precipitation is distributed evenly throughout the year with a small maximum in autumn and winter. Their number is greater than in the previous type.

The Mediterranean and temperate continental types are characterized by a decrease in the total amount of precipitation as one moves deeper into the continents.

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Atmospheric precipitation is one of the meteorological elements strongly dependent on a number of local landscape features.

Let us try, however, to trace what conditions influence their distribution.

First of all, it is necessary to note the value of air temperature. The temperature decreases from the equator to the poles; consequently, both the intensity of evaporation and the moisture capacity of the air decrease in the same direction. In cold regions, evaporation is small, and cold air is not able to dissolve much water vapor in itself; therefore, during condensation, a large amount of precipitation cannot be released from it. In warm regions, strong evaporation and a high moisture capacity of air lead, when water vapor condenses, to abundant precipitation. Thus, a regularity must inevitably manifest itself on Earth, which consists in the fact that in warm regions there is especially a lot of precipitation, while in cold regions there is little of it. This regularity actually manifests itself, but, like other phenomena in nature, it is complicated, and in some places completely obscured by a number of other influences, and above all by the circulation of the atmosphere, the nature of the distribution of land and sea, relief, height above ocean level and sea currents.

Knowing the conditions necessary for the condensation of water vapor, it is possible to predict how the circulation of the atmosphere affects the distribution of precipitation. Since air is a carrier of moisture, and its movement covers vast areas on Earth, this inevitably leads to a smoothing of differences in the amount of precipitation due to the distribution of temperatures in areas where the air experiences uplifts (above the equator, in cyclones, on the windward slopes of mountain ranges), an environment favorable for precipitation is created, and all other factors become subordinate. In those places where descending air movements predominate (in subtropical maxima, in anticyclones in general, in the area of ​​the trade winds, on the leeward slopes of mountains, etc.), precipitation is much less.

It is generally accepted that the amount of precipitation in a given area is highly dependent on its proximity to the sea or its distance from the sea. In fact, many examples are known when very dry regions of the Earth are located on the ocean coasts and, conversely, far from the sea, inland (as, for example, on the eastern slope of the Andes in the upper reaches of the Amazon), a huge amount of precipitation falls. The point here is not so much in the distance from the sea, but in the nature of the circulation of the atmosphere and the structure of the surface, that is, in the absence or presence of mountain ranges that interfere with the movement of air masses carrying moisture. During the southwestern monsoon in India, air masses pass over the Thar Desert without irrigating it with rain, since the flat relief does not impede the movement of air, and the heated desert has a rather drying effect on the air masses.

Types of precipitation.

But the same monsoon on the windward slope of the Western Ghats, not to mention the southern slopes of the Himalayas, leaves a huge amount of moisture.

The need to single out orographic precipitation as a special type testifies to the exceptionally large role of the structure of the earth's surface in the distribution of precipitation. True, in this case, as in all others, the relief is important not only in itself, as a mechanical obstacle, but in combination with absolute height and atmospheric circulation.

The penetration of warm sea currents into high latitudes contributes to the formation of precipitation due to the fact that cyclonic circulation of the atmosphere is associated with warm currents. Cold currents have the opposite effect, since spurs of high pressure usually develop above them.

Of course, none of these factors affects the distribution of precipitation independently of the others. In each case, the precipitation of atmospheric moisture is regulated by a complex and sometimes contradictory interaction of both general and local agents. However, leaving aside the details, one of the main conditions determining the distribution of precipitation in the landscape envelope is still temperature, general circulation atmosphere and relief.

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Water molecules continuously evaporating 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. Water vapor is always present in the air, which is usually impossible to see, but the humidity of the air depends on its amount.

Humidity is different in all areas the globe, in the heat it rises when evaporation from the surface of water bodies into the atmosphere increases. Low humidity is usually observed over desert areas, as there is little water vapor, so the air in deserts is very dry.

Water vapor overcomes many challenges 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 are much lighter than cold ones, they rise. Tiny water droplets that formed in the air continue to travel further with it into precipitation.

Types of precipitation, fog and clouds.

To imagine how the further transformation of water vapor in the atmosphere occurs, a fairly simple experiment can be carried out. It is necessary 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 droplets will form on it. The released steam turned into water, which means that a phenomenon called condensation has 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 drops form, which can be observed from the earth in the form of clouds.

When flying on an airplane, you can see how the clouds sometimes appear below the aircraft. And you can even be among the clouds if you climb a high mountain with low cloud cover. At this moment, the surrounding objects and people will turn into invisible people, who were swallowed up by a thick veil of fog. Fog is the same clouds, but only located near the 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 from thunderclouds rain falls on the ground in precipitation.

Dew and frost as types of precipitation.

In the summer near water bodies, a lot of steam is formed in the air and it becomes highly saturated with water pores. With the onset of night, coolness comes and at this time a smaller amount of 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 can be seen covering various objects.

With coming late autumn the temperature during the night can drop below 0 ° C, then the dew drops freeze and turn into amazing transparent crystals, which are called frost.

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

• tree branches;
• loose surface of the earth;
• wooden benches.

Snow and hail as types of precipitation.

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

When air currents bring water vapor to a height of about 5 km, then water droplets begin to settle on dust particles, while they instantly freeze. The formed ice crystals begin to increase in size, and reaching heavy weight I start to fall. But a new stream of warm air comes from the earth 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, only after gaining enough heavy weight they fall to the ground.

The size of such types of precipitation(hailstones) usually ranges from 1 to 5 mm in diameter. Although there were cases when the size of hailstones exceeded egg, and the weight reached about 400-800 g.

Hail can cause a lot of damage agriculture, it damages gardens and crops, and also leads to the death of small animals. Large hailstones can damage cars and even pierce the skin of aircraft.

To reduce the likelihood of hail falling to the ground, scientists are constantly developing new substances that, with the help of special rockets, are thrown into thunderclouds and thus they are dispersed.

With the advent of winter, the earth is enveloped in a snow-white blanket, consisting of the smallest ice crystals, which are called snow. Due to low temperatures, water droplets freeze and ice crystals form in the clouds, then new water molecules are attached 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. If the snowflakes are affected by the current of the wind, they stick together and form snow flakes. Walking on the snow in frosty weather, we often hear a crunch under our feet, it is ice crystals that break in the snowflakes.

Such types of precipitation, as snow brings many problems, because of snow, traffic is difficult on roads, power lines are torn under its weight, and snowmelt leads to floods. But due to the fact that the plants are covered with a snow blanket, they are able to endure even severe frosts.

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

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

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

Types of precipitation

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

Liquid precipitation

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

Rain

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

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

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

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

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

Dew

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

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

Solid atmospheric precipitation

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

Snow

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

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

hail

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

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

Frost

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

rainy seasons

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

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

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