Message precipitation. How is precipitation formed? Precipitation. Pattern and types of precipitation

Precipitation - water in a liquid or solid state that falls from clouds or settles from the air onto the earth's surface.

Rain

Under certain conditions, cloud droplets begin to merge into larger and heavier ones. They can no longer stay in the atmosphere and fall to the ground in the form rain.

hail

It happens that in the summer the air quickly rises and picks up rain clouds and carries them to a height where the temperature is below 0°. Raindrops freeze and fall out as hail(Fig. 1).

Rice. 1. Origin of the hail

Snow

IN winter time in temperate and high latitudes precipitation falls in the form snow. Clouds at this time do not consist of water droplets, but of tiny crystals - needles, which, joining together, form snowflakes.

Dew and frost

Precipitation falling onto the earth's surface not only from clouds, but also directly from the air is dew And frost.

The amount of precipitation is measured by a precipitation gauge or rain gauge (Fig. 2).

Rice. 2. Structure of the rain gauge: 1 - outer casing; 2 - funnel; 3 - container for collecting oxen; 4-dimensional tank

Classification and types of precipitation

Precipitation is distinguished by the nature of precipitation, by origin, by physical state, by seasons of precipitation, etc. (Fig. 3).

According to the nature of precipitation, precipitation can be torrential, heavy and drizzling. Rainfall - intense, short-lived, cover a small area. Cover precipitation - medium intensity, uniform, long-term (can last for days, involving large areas). Drizzle - fine precipitation falling over a small area.

Precipitation is classified according to its origin:

• convective - characteristic of the hot zone, where heating and evaporation are intense, but often occur in the temperate zone;
• frontal - are formed when two air masses meet different temperatures and fall out of more warm air. Characteristic for temperate and cold zones;
• orographic - fall on the windward slopes of the mountains. They are very abundant if the air comes from the side warm sea and has high absolute and relative humidity.

Rice. 3. Types of precipitation

Comparing to climate map annual quantity atmospheric precipitation in the Amazonian lowland and in the Sahara desert, one can see their uneven distribution (Fig. 4). What explains this?

Precipitation comes from moist air masses that form over the ocean. This is clearly seen in areas with a monsoon climate. Summer monsoon brings a lot of moisture from the ocean. And there are continuous rains over the land, as on the Pacific coast of Eurasia.

Constant winds also play a big role in the distribution of precipitation. Thus, trade winds blowing from the continent bring dry air to northern Africa, where the largest desert in the world is located - the Sahara. Western winds bring rain to Europe from the Atlantic Ocean.

Rice. 4. Average annual distribution of precipitation on Earth's land

As you already know, sea currents affect precipitation in the coastal parts of continents: warm currents contribute to their appearance (Mozambique Current off the eastern coast of Africa, Gulf Stream off the coast of Europe), cold currents, on the contrary, prevent precipitation (Peruvian Current off the western coast of South America) .

Relief also affects the distribution of precipitation, for example, the Himalayan mountains do not allow moist winds blowing from the Indian Ocean to pass to the north. Therefore, on their southern slopes sometimes up to 20,000 mm of precipitation falls per year. Moist air masses, rising along the mountain slopes (ascending air currents), cool, become saturated, and precipitation falls from them. The territory north of the Himalayan mountains resembles a desert: only 200 mm of precipitation falls there per year.

There is a relationship between belts and precipitation. At the equator - in the belt low pressure— constantly heated air; rising upward, it cools and becomes saturated. Therefore, in the equator region there are many clouds and heavy rainfall. A lot of precipitation also falls in other areas of the globe where low pressure prevails. Wherein great importance has an air temperature: the lower it is, the less precipitation falls.

In belts high pressure downward air currents predominate. As the air descends, it heats up and loses the properties of its saturation state. Therefore, at latitudes 25-30° precipitation occurs rarely and in small quantities. Areas of high pressure near the poles also receive little precipitation.

Absolute maximum precipitation registered on o. Hawaii (Pacific Ocean) - 11,684 mm/year and in Cherrapunji (India) - 11,600 mm/year. The absolute minimum - in the Atacama Desert and the Libyan Desert - less than 50 mm/year; Sometimes there is no precipitation at all for years.

The moisture content of the area is characterized by humidification coefficient— the ratio of annual precipitation and evaporation for the same period. The humidification coefficient is denoted by the letter K, the annual amount of precipitation by the letter O, and evaporation by the letter I; then K = O: I.

The lower the humidification coefficient, the drier the climate. If the annual precipitation is approximately equal to evaporation, then the humidification coefficient is close to unity. In this case, hydration is considered sufficient. If the moisture index is greater than one, then the moisture excessive, less than one - insufficient. When the humidification coefficient is less than 0.3, humidification is considered meager. Zones with sufficient moisture include forest-steppes and steppes, and zones with insufficient moisture include deserts.

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

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

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 temperatures in the upper layer. In this case, spherical snowballs with rising air currents rise to the upper parts of the cloud with more low temperatures and freeze to form spherical pieces of ice - hailstones. Then, under the influence of gravity, the hailstones fall to the Earth. They usually vary in size and can range in diameter from a pea to a chicken egg.

Types of precipitation

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

Maximum precipitation is observed in equatorial belt(up to 2000 mm per year), minimum - in the tropics and polar regions (200-250 mm per year). In the temperate zone, the average annual precipitation is 500-600 mm per year.

In every climatic zone There is also unevenness in precipitation. This is explained by the terrain features 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 edges it falls more than half as much. Areas of land have been identified where there is almost no precipitation. These are the Atacama Desert, the central regions of the Sahara. In these regions, the average annual precipitation is less than 50 mm. Huge amounts of rainfall are observed in the southern regions of the Himalayas, in Central Africa(up to 10,000 mm per year).

Thus, the defining features of the climate of a given area are the average monthly, seasonal, and average annual precipitation, its 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 materials:

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 loss is usually several hours (and sometimes 1-2 days), but in 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 drops of rain 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 (the 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.

Rain with snow- 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 precipitation of a torrential nature is not its high intensity (storm precipitation can be weak), but the very fact of precipitation from convective (most often cumulonimbus) clouds, which determines fluctuations in the intensity of precipitation. In hot weather, light showers may 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, the 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 event, which occurs during weak 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 sunlight, but in cloudy weather and can remain in the shade 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 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 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.

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

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

Precipitation formation

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

Types of precipitation

Such types of precipitation as dew, frost, frost, ice, fog are formed in the surface layers of the atmosphere due to the condensation of water vapor on objects. Dew appears at higher temperatures, frost and frost - at negative temperatures. When there is an excessive concentration of water vapor in the surface atmospheric layer, fog appears. When 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 average, our planet receives approximately 1000 mm of precipitation per year. To measure the amount of precipitation, a device such as a rain gauge is used. For many years, observations have been made of the amount of precipitation in different regions of the planet, thanks to which general patterns of its distribution over the earth's surface have been established.

The maximum amount of precipitation is observed in the 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 precipitation is 500-600 mm per year.

In each climate zone, there is also unevenness in precipitation. This is explained by the terrain features 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 edges it falls more than half as much. Areas of land have been identified where there is almost no precipitation. These are the Atacama Desert, the central regions of the Sahara. In these regions, the average annual precipitation is less than 50 mm. Huge amounts of precipitation are observed in the southern regions of the Himalayas and Central Africa (up to 10,000 mm per year).

Thus, the defining features of the climate of a given area are the average monthly, seasonal, and average annual precipitation, its 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 materials:

Atmosphere

Atmosphere pressure

The meaning of atmosphere

Types of precipitation

There are different classifications for precipitation.

Atmospheric precipitation and its chemical composition

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

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

Measuring precipitation is essential for any geographic research. After all, precipitation is one of the most important links in moisture circulation on the globe.

The defining characteristics for a particular climate are considered to be the average monthly, annual, seasonal and long-term amount of precipitation, its daily and annual cycle, its frequency and intensity.

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

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

Exist different types rain: icy, freezing and rain with snow. Both freezing rain and ice rain fall at subzero air temperatures.

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

A freezing rain represented by sediments in a solid state - these are ice balls with frozen water inside. Snow is precipitation that falls in the form of flakes and snow crystals.

Horizontal visibility depends on the intensity of snowfall. A distinction is made 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 weather. Weather is the most variable phenomenon in environment. It will start to rain, then the wind will start, and after a few hours the sun will shine and the wind will subside.

But even the variability of weather has its own patterns, despite the fact that the formation of weather is influenced by a huge number of factors.

The main elements characterizing the weather include the following meteorological indicators: solar radiation, Atmosphere pressure, air humidity and temperature, precipitation and wind direction, wind strength and cloudiness.

If we talk about weather variability, then most often it changes in temperate latitudes - in regions with continental climate. And most stable weather occurs in polar and equatorial latitudes.

Weather changes are associated with the change of season, that is, changes are periodic, and over time weather are repeated.

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

Climate concept

The long-term weather pattern is called climate. Climate is determined in a specific area - thus, the weather pattern 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 over several decades.

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Cover precipitation

Long-term (from several hours to a day or more) precipitation in the form of rain (covered rain) or snow (covered snow), falling over a large area with a fairly uniform intensity from nimbostratus and altostratus clouds on a warm front. Continuous precipitation moisturizes the soil well.

Rain- liquid precipitation in the form of droplets with a diameter of 0.5 to 5 mm. Individual drops of rain 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 forms when falling snowflakes hit a layer of warm air deep enough for the snowflakes to completely melt and become raindrops. As these droplets continue to fall, they pass through a thin layer of cold air above the earth's surface and their temperature drops below freezing. However, the droplets themselves do not freeze, so this phenomenon is called supercooling (or the formation of “supercooled droplets”).

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. Formed when raindrops freeze as they fall through bottom layer air with negative temperatures. 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 (the 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.

Rain with snow- mixed precipitation that falls (most often at positive air temperatures) in the form of a mixture of drops and snowflakes.

Precipitation

If rain and snow fall at subzero air temperatures, precipitation particles freeze onto objects and ice forms.

Drizzle

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.

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

Rainfall

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

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 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, the 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.

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.

Many factors determine how much rain or snow will fall on the earth's surface. These are temperature, altitude, location 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. Cherrapunjee in India has perhaps the second highest rainfall with an average annual rainfall ranging from 1079 to 1143 cm. Once 381 cm of rain fell in Cherrapunjee in 5 days. And in 1861 the amount of precipitation reached 2300 cm!

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

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

In some vast regions of the Earth heavy showers there are all year round. For example, almost every point along the equator receives 152 cm or more of precipitation every year. The equator is the junction point of two large air currents. Everywhere along the equator, air moving down from the north meets air moving up from the south.

There is a basic upward movement of hot air mixed with water vapor. As air rises to colder heights, large amounts of water vapor condense and fall as rain.

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

Precipitation. Pattern and types of precipitation

Cooling causes water vapor to condense, which falls as rain or snow.

Depending on the nature of cloudiness and precipitation regime, two types of their daily cycle are distinguished: continental and maritime. The continental type is characterized by two maxima: the main one - in the afternoon from convective cumulonimbus, and at the equator and from cumulus clouds and a minor one - in the early 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 maximum of precipitation 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, and in temperate zones possible only in summer.

The annual course of precipitation, i.e., its change by month during the year, in different places The earth is very different. This depends on many factors: radiation regime, general atmospheric circulation, specific physical-geographical situation, etc. Several main types can be outlined annual progress precipitation and express them in the form of bar graphs (Fig. 47).

Rice. 47. Types of annual precipitation using the example of the northern hemisphere

Equatorial type - heavy precipitation falls fairly evenly throughout the year, there are no dry months, two small maximums are noted - 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 variation of precipitation due to the dryness of winter is expressed very sharply, as well as the eastern coasts of continents in subtropical and temperate latitudes. However, the annual amplitude of precipitation here is somewhat smoothed out, especially in the subtropics, where frontal rains also occur in winter. The annual amount of precipitation 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, there are two main types of annual precipitation: continental and marine. The continental (inland) type is distinguished by the fact that in summer there is two to three times more precipitation than in winter, due to frontal and convective precipitation.

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

Mediterranean and temperate continental types are characterized by a decrease total number precipitation as we move deeper into the continents.

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Publication date: 2014-11-19; Read: 2576 | Page copyright infringement

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

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

First of all, it is necessary to note the air temperature. 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 areas, evaporation is small, and cold air is not able to dissolve much water vapor; therefore, during condensation, a large amount of precipitation cannot be released from it. In warm regions, strong evaporation and high moisture capacity of the air lead to the condensation of water vapor to abundant precipitation. Thus, a pattern must inevitably appear on Earth, namely that in warm regions there is especially a lot of precipitation, while in cold regions there is little of it. This pattern 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 atmospheric circulation, the nature of the distribution of land and sea, relief, altitude and sea currents.

Knowing the conditions necessary for the condensation of water vapor, it is possible to predict how atmospheric circulation affects the distribution of precipitation. Since air is a carrier of moisture, and its movement covers vast spaces on Earth, this inevitably leads to smoothing out differences in the amount of precipitation caused by temperature distribution in areas where the air experiences rises (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 downward air movements predominate (in subtropical highs, in anticyclones in general, in the area of ​​trade winds, on the leeward slopes of mountains, etc.), there is much less precipitation.

It is generally accepted that the amount of precipitation in a given area in high degree depends on its proximity to the sea or distance from the sea. In fact, there are many examples where very dry areas 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), huge amounts of precipitation fall. The point here is not so much the distance from the sea, but the nature of atmospheric circulation and surface structure, i.e., the absence or presence of mountain ranges that interfere with the movement of air masses carrying moisture. During the southwest monsoon in India, air masses pass over the Thar Desert without irrigating it with rain, since the flat terrain 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 distinguish orographic sediments into a special type indicates exclusively big role arrangement of the earth's surface in the distribution of precipitation. True, in this case, as in all others, the relief matters 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 high pressure spurs usually develop above them.

Of course, none of these factors affects the distribution of precipitation independently of the others. In each case, the loss of atmospheric moisture is regulated by a complex and sometimes contradictory interaction of both general and local agents. However, if we ignore the details, the main conditions that determine the placement of precipitation in the landscape envelope still include temperature, general atmospheric circulation and relief.

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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 physical and chemical 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 2nd grade in the subject “The World Around us”.

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 air layer, and are also associated with the transition of water dispersion into various states of aggregation and precipitation onto the surface of the planet.

The main classification of precipitation is separation by temperature of atmospheric fronts:

• cover– associated with warm air currents;
• stormwater– associated with cold air masses.

To take into account the amount of precipitation that falls on the surface of the Earth in a certain region, meteorologists use special equipment - precipitation gauges, which provide data measured in the thickness of the layer of liquid water falling on a solid surface. Units of measurement are millimeters per year.

Natural precipitation plays a key role in the formation of the earth's climate and shapes the circulation of water in nature.

Types of precipitation

The types of precipitation can be conditionally divided based on the aggregate state of water in which it falls on 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);
• hard- (snow, hail and frost).

Let's figure out what each type of precipitation is.

The most common type of precipitation is rain(refers to convective precipitation). This phenomenon is formed under the influence of the radiant energy of the Sun, which heats the moisture located on the surface of the Earth and evaporates it.

Once in 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 divided depending on the size of the drops, which in turn is related to air currents and temperature.

A type of rain is formed like this - if the air is warm, then it forms larger drops, and if it is cold, then light drizzle (supercooled rain) can be observed. When the temperature drops, rain and snow fall.

Another process associated with condensation is dew fall. This physical phenomenon based on the fact that a certain volume of air can contain a strictly defined amount of steam at a given temperature.

Until the maximum volume of steam 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 early in the morning on the street, looking at the dew, flowers and other solid objects.

Another common type of precipitation is snow. Fundamentally, its formation is similar to the formation of rain, but 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 snowflake formation occurs in the air and under the influence different temperatures, then this causes a large number of shapes and crystals of snowflakes.

If the temperature is very low, then cover snow forms; if it is closer to zero, then shower snow. Wet snow forms at temperatures just above freezing.

One of the dangerous atmospheric phenomena- This hail Its formation occurs mainly in the summer, when heated air currents carry vaporous moisture into 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 often cause 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 rate relative humidity air.

At the same time, given the negative temperature, the condensed moisture immediately freezes on hard surfaces, forming frost.

Types of precipitation by season

A characteristic based on the seasonality of precipitation is often used.

So, there are:

• precipitation that falls mainly during the warm season– rain, drizzle (subtype of rain), dew, hail;
• precipitation that occurs during the cold season– snow, groats (a subtype of snow), hoarfrost, hoarfrost, ice.

Types of precipitation by formation height

A more accurate classification is one that takes into account the altitude at which the condensate was converted into one of the types of precipitation:

• Precipitation that forms in the upper and middle layers of the atmosphere includes rain, drizzle, hail, pellets 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 from the air.

How is precipitation measured?

You can often hear in the weather forecast that 2 millimeters of precipitation fell per day. Meteorologists and weather forecasters determine such data at weather stations using special equipment - precipitation gauges.

These are graduated buckets (on which conventional signs), made in a certain standard size, which are installed outdoors.

Every day, in the period 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 measuring cylinder (cylinder divisions are made in mm).

The obtained values ​​are entered into the accounting journal, forming a precipitation table. If the precipitation was solid, then it is allowed to melt it.

To build a visual picture, points with measured precipitation amounts are indicated on the map. These points are connected into a diagram by lines - isohyets, and the space is painted with the colors of precipitation with increasing intensity.

How precipitation affects aviation operations

There are a number of very important atmospheric factors that make aviation difficult. First of all, this is related to ensuring flight safety.

The main ones:

1. First of all, this is a deterioration in visibility for aircraft pilots. Visibility in heavy rain or snow storm decreases to 1.5-2 km, which makes visual control of the course difficult.
2. During takeoff or landing, moisture condensation on glass or optical reflectors can lead to a distorted perception of information by the pilot.
3. A large amount of fine water dust entering the engine can hinder and disrupt its operation.
4. When the aerodynamic elements of an aircraft (wings, steering elements) become icy, a loss of flight characteristics occurs.
5. When there is a significant amount of precipitation, contact with the runway surface becomes difficult.

Thus, all precipitation, as applied to aviation, is extremely unfavorable.

Precipitation is a key factor in shaping the Earth's climate, and geographical 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 water cycle on the planet.