What is water vapor? What properties does it have?
Water vapor - gaseous state water. It has no color, taste or smell. Contained in the troposphere. Formed by water molecules during its evaporation. When water vapor cools, it turns into water droplets.
In what seasons of the year does it rain in your area? When does it snow?
Rain falls in summer, autumn, and spring. Snowfalls - winter, end of autumn, beginning of spring.
Using Figure 119, compare the average annual precipitation in Algeria and Vladivostok. Is precipitation distributed equally across months?
The annual precipitation in Algeria and Vladivostok is almost the same - 712 and 685 mm, respectively. However, their distribution throughout the year differs. In Algeria, maximum precipitation occurs in late autumn and winter. Minimum - at summer months. In Vladivostok, most of the precipitation falls in summer and early autumn, with the minimum falling in winter.
Look at the picture and tell us about the alternation of belts with different annual precipitation amounts.
The distribution of precipitation generally shows changes in the direction from the equator to the poles. In a wide strip along the equator, the largest amount of precipitation falls - over 2000 mm per year. In tropical latitudes there is very little precipitation - on average 250-300 mm, and in temperate latitudes it again becomes more. With further approach to the poles, the amount of precipitation again decreases to 250 mm per year or less.
Questions and tasks
1. How are precipitation formed?
Atmospheric precipitation is water that falls to the ground from clouds (rain, snow, hail) or directly from the air (dew, frost, frost). Clouds are made up of tiny droplets of water and ice crystals. They are so small that they are held by air currents and do not fall to the ground. But droplets and snowflakes can merge with each other. Then they increase in size, become heavy and fall to the ground in the form of precipitation.
2. Name the types of precipitation.
Precipitation can be liquid (rain), solid (snow, hail, pellets) and mixed (snow and rain)
3. Why does the collision of warm and cold air lead to precipitation?
When faced with cold air warm air, displaced by the heavy cold, rises up and begins to cool. Water vapor in warm air condenses. This leads to the formation of clouds and precipitation.
4. Why does precipitation not always fall in cloudy weather?
Precipitation only occurs if the air is oversaturated with moisture.
5. How can you explain that there is a lot of precipitation near the equator, but very little near the poles?
Large amounts of precipitation fall near the equator, as high temperatures cause large amounts of moisture to evaporate. The air quickly becomes saturated and precipitation occurs. At the poles, low air temperatures prevent evaporation.
6. How much precipitation falls per year in your area?
In the European part of Russia, an average of about 500 mm will fall per year.
Water 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 solids(dust particles), the condensation process proceeds faster, since they act as condensation nuclei. At subzero 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, 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 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 their distribution have been established. 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 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, high latitudes and deserts receive about 250 mm of precipitation per year, and the globe as a whole receives about 1,000 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.
And freezing rain is represented by precipitation 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 the 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, atmospheric 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 a continental climate. And most stable weather occurs in polar and equatorial latitudes.
Changes in weather are associated with changes in seasons, that is, changes are periodic, and weather conditions repeat over time.
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 raindrops leave a mark on the surface of water in the form of a diverging circle, and on the surface of dry objects - in the form of a wet spot.
Freezing rain- liquid precipitation in the form of drops with a diameter of 0.5 to 5 mm, falling at negative air temperatures (most often 0...-10°, sometimes up to -15°) - falling on objects, the drops freeze and ice forms. Freezing rain 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. They are formed when raindrops freeze as they fall through the lower layer of air with a negative temperature. 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 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 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. 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.
Some large regions of the Earth experience heavy rainfall 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 from the 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 are observed throughout the year in the hot zone, and in temperate zones they are possible only in summer.
The annual course of precipitation, i.e., its change by month during the year, is very different in different places on the Earth. This depends on many factors: radiation regime, general atmospheric circulation, specific physical-geographical situation, etc. Several main types of annual precipitation can be outlined and expressed in the form of bar charts (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 very pronounced, 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.
The Mediterranean and temperate continental types are characterized by a decrease in the total amount of precipitation as one moves inland.
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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 unable to dissolve a lot of 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 highly 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 precipitation into a special type indicates the extremely important role of the structure 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 warm currents associated cyclonic circulation of the atmosphere. 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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In understanding ordinary person, precipitation is rain or snow. In fact, there are many more species and all of them, one way or another, are found throughout the year. Among them there are very unusual phenomena that lead to beautiful effects. What kind of precipitation occurs?
Rain
Rain is the fall of water drops from the sky to the ground as a result of its condensation from the air. During the process of evaporation, water collects into clouds, which later turn into clouds. At a certain moment, the smallest droplets of steam increase, becoming the size of raindrops. Under own weight, they fall to the surface of the earth.
Rains can be continuous, torrential and drizzle. Covering rain occurs over a long period of time and is characterized by a smooth beginning and end. The intensity of falling drops remains virtually unchanged throughout the rain.
Rainfall is characterized by short duration and large droplet size. They can reach five millimeters in diameter. Drizzling rain has droplets less than 1 mm in diameter. It is practically a fog that hangs above the surface of the earth.
Snow
Snow is the precipitation of frozen water, in the form of flakes or frozen crystals. In another way, snow is called dry residues, since snowflakes falling on a cold surface do not leave wet marks.
In most cases, heavy snowfalls develop gradually. They are characterized by smoothness and lack of sudden change intensity of loss. In severe frost, snow may appear from a seemingly clear sky. In this case, snowflakes are formed in the thinnest cloud layer, which is practically invisible to the eye. Such snowfall is always very light, since a large snow charge requires appropriate clouds.
Rain with snow
This classic look precipitation in autumn and spring. It is characterized by the simultaneous fall of both raindrops and snowflakes. This happens due to slight fluctuations in air temperature around 0 degrees. Different layers of clouds produce different temperatures, and they also differ on the way to the ground. As a result, some of the drops freeze into snow flakes, and some fly in a liquid state.
hail
Hail is the name given to pieces of ice into which, under certain conditions, water turns before falling to the ground. The size of hailstones ranges from 2 to 50 millimeters. This phenomenon occurs in the summer, when the air temperature is above +10 degrees and is accompanied by heavy rain and thunderstorms. Large hailstones can cause damage to vehicles, vegetation, buildings and people.
Snow pellets
Snow pellets are dry precipitation in the form of dense, frozen snow grains. They differ from ordinary snow in their high density, small size (up to 4 millimeters) and almost round shape. Such grain appears at temperatures around 0 degrees, and may be accompanied by rain or real snow.
Dew
Dew droplets are also considered precipitation, but they do not fall from the sky, but appear on various surfaces as a result of condensation from the air. For dew to appear, a positive temperature, high humidity, and absence of strong wind. Heavy dew can lead to water flowing over the surfaces of buildings, structures, and vehicle bodies.
Frost
This is "winter dew". Frost is water that has condensed from the air but has passed the liquid stage. It looks like a lot of white crystals covering, as a rule, horizontal surfaces.
frost
It is a type of frost, but does not appear on horizontal surfaces, but on thin and long objects. As a rule, in humid and frosty weather they become covered with frost. umbrella plants, power line wires, tree branches.
Ice
Glaze is a layer of ice on any horizontal surfaces that appears as a result of cooling fog, drizzle, rain or sleet with subsequent temperature drops below 0 degrees. As a result of ice buildup, weak structures can collapse and power line wires can break.
Black ice is a special case of ice that forms only on the surface of the earth. Most often, it forms after a thaw and subsequent drop in temperature.
Ice needles
This is another type of precipitation, which consists of tiny crystals floating in the air. Ice needles are perhaps one of the most beautiful winter atmospheric phenomena, as they often lead to various light effects. They are formed at air temperatures below -15 degrees and refract passing light in their structure. The result is halos around the sun, or beautiful "pillars" of light extending from street lamps into clear, frosty skies.
Atmospheric precipitation is usually understood as water falling from the atmosphere to the surface of the earth. They are measured in millimeters. For measurements, special instruments are used - precipitation gauges or weather radars, which allow measuring different types of precipitation over a large area.
On average, the planet receives about a thousand millimeters of precipitation per year. All of them are not evenly distributed across the Earth. The exact level depends on the weather, terrain, climate zone, proximity of water bodies and other indicators.
What types of precipitation are there?
From the atmosphere, water reaches the surface of the earth in two states: liquid and solid. Because of this feature, all types of precipitation are divided into:
- Liquid. These include rain and dew.
- Solids are snow, hail, frost.
There is a classification of precipitation types according to their shape. This is how rain is released in drops of 0.5 mm or more. Anything less than 0.5 mm is considered drizzle. Snow is ice crystals with six corners, but round solid sediments are graupel. It consists of round-shaped kernels of different diameters, which are easily compressed in the hand. Most often, such precipitation occurs at temperatures close to zero.
Hail and ice pellets are of great interest to scientists. These two types of sediment are difficult to crush with your fingers. The grain has an icy surface; when it falls, it hits the ground and bounces off. Hail is large ice that can reach eight centimeters or more in diameter. This type of precipitation usually forms in cumulonimbus clouds.
Other types
The finest type of precipitation is dew. These are tiny droplets of water that form during the process of condensation on the soil surface. When they come together, you can see dew on various objects. Favorable conditions for its formation are clear nights, when ground objects cool. And the higher the thermal conductivity of an object, the more dew forms on it. If the temperature environment falls below zero, a thin layer of ice crystals or frost appears.
In weather forecasting, precipitation most often refers to rain and snow. However, not only these types are included in the concept of precipitation. This also includes liquid plaque, which forms in the form of drops of water or in the form of a continuous film of water in cloudy, windy weather. This type of precipitation is observed on the vertical surface of cold objects. At sub-zero temperatures, the coating becomes hard, and thin ice is most often observed.
The loose white sediment that forms on wires, ships, and more is called rime. This phenomenon is observed in foggy frosty weather with low winds. Frost can quickly build up, breaking wires and light ship equipment.
Freezing rain is another unusual sight. It occurs at subzero temperatures, most often from -10 to -15 degrees. This type has some peculiarity: the drops look like balls, covered with ice on the outside. When they fall, their shell breaks and the water inside splashes out. Under the influence of negative temperatures, it freezes, forming ice.
Precipitation is also classified according to other criteria. They are divided by the nature of the loss, by origin and more.
Character of loss
According to this qualification, all precipitation is divided into drizzle, shower, and heavy precipitation. The latter are intense, uniform rains that can last for a long time - a day or longer. This phenomenon covers quite large areas.
Drizzle falls over small areas and consists of small drops of water. Rainfall refers to rainfall. It is intense, does not last long, and covers a small area.
Origin
Based on their origin, precipitation is divided into frontal, orographic and convective precipitation.
Orographic fall out on mountain slopes. They flow most abundantly if warm air with relative humidity comes from the sea.
The convective type is characteristic of the hot zone, where heating and evaporation occur with high intensity. The same species is found in the temperate zone.
Frontal precipitation is formed when air masses with different temperatures meet. This species is concentrated in cold, temperate climates.
Quantity
Meteorologists long time monitor precipitation and its quantity, indicating its intensity on climate maps. So, if you look at annual maps, you can trace the unevenness of precipitation around the world. The rains are most intense in the area of the Amazon River, but in the Sahara Desert there is little rainfall.
The unevenness is explained by the fact that precipitation is brought by moist air masses that form over the oceans. This is most clearly visible in areas with a monsoon climate. Most moisture comes into summer time with the monsoons. There are continuous rains over land, such as on the Pacific coast of Europe.
Winds play a significant role. Blowing from the continent, they carry dry air to northern Africa, where the world's largest desert is located. And winds bring rain from the Atlantic to European countries.
Precipitation in the form of showers is influenced by sea currents. Warm promotes their appearance, while cold, on the contrary, prevents them.
The terrain plays an important role. The Himalayan mountains do not allow moist winds from the ocean to pass to the north, which is why up to 20 thousand millimeters of precipitation falls on their slopes, but on the other hand, there is practically none.
Scientists have found that there is a relationship between atmospheric pressure and amount of precipitation. On the equator, in the low pressure zone, the air is constantly heated, it forms clouds and heavy rains. Large amounts of precipitation also occur in other areas of the Earth. However, where low temperature air, precipitation does not often occur in the form freezing rain and snow.
Fixed data
Scientists are constantly recording rainfall amounts around the world. to the globe. The highest recorded precipitation is in the Hawaiian Islands, located in Pacific Ocean, in India. Over 11,000 millimeters fell in these areas during the year. The minimum was recorded in the Libyan Desert and Atakami - less than 45 millimeters per year, sometimes in these areas there is no precipitation at all for several years.
Precipitation- water in a liquid or solid state that falls from clouds or precipitates directly from the air onto the surface of the Earth. These include:
Rain. The smallest droplets of water, with a diameter of 0.05 to 0.1 mm, that make up the clouds, merging with each other, gradually increase in size, become heavy and fall to the ground in the form of rain. The stronger the ascending jets of air from the sun-heated surface, the larger the falling drops should be. Therefore, in the summer, when the surface air is heated by the earth and rapidly rises, rain usually falls in the form of large drops, and in the spring and autumn - drizzle. If rain falls from stratus clouds, then such rain is blanket rain, and if it falls from stratus clouds, it is torrential. It is necessary to distinguish drizzle from rain. This type of precipitation usually falls from stratus clouds. The droplets are much smaller in size than raindrops. The speed of their fall is so slow that they appear suspended in the air.
Snow. It is formed when the cloud is in air with a temperature below 0°. Snow consists of crystals of various shapes. The most 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 upward air currents in the warm season. Droplets of water, falling to great heights 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 hail reaches the size of a chicken egg, usually with varying layers of density. Typically, hail falls from powerful cumulonimbus clouds during rainfall. The frequency of hail varies: in it 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 causes great material damage: it destroys crops, vineyards, and if the hailstones are large in size, then it can cause the destruction of houses and the death of people. In our country, methods for identifying hail clouds have been developed and hail control services have been created. Dangerous clouds are “shot” with special chemicals.
Rain, snow, and hail are called hydrometeorites. In addition to them, precipitation also includes those that are deposited directly from the air. These include dew, fog, frost, etc.
Dew(Latin ros - moisture, liquid) - precipitation in the form of water droplets deposited on the surface of the earth and ground objects when the air cools. In this case, water vapor, cooling, changes from a state to liquid and settles. Most often, dew is observed 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. visibility is sometimes reduced to several meters. Advective fogs are distinguished by their origin (due to the cooling of warm humid air above the colder surface of land or water) and radiation (formed as a result of cooling of the earth's surface). In a number of regions of the Earth there are often fogs on the coasts in places where cold currents pass. For example, Atacama is located on the coast. It's cold 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.
