The temperature and precipitation are the most. Precipitation, their forms and types

PRECIPITATION

PRECIPITATION, in meteorology, all forms of water, liquid or solid, that fall out of the atmosphere onto the earth. Precipitation differs from CLOUD, FOG, DEW and FROST in that it falls and reaches the ground. Includes rain, drizzle, SNOW and hail. They are measured by the thickness of the layer of precipitated water and are expressed in millimeters. Precipitation occurs due to the CONDENSATION of cloud water vapor into small water particles, which merge into large drops with a diameter of about 7 mm. Precipitation also forms from melting ice crystals in clouds. Drizzle consists of very small droplets, and snow - of ice crystals, mainly in the form of hexagonal plates and six-pointed stars. Groats formed when raindrops freeze and turn into small ice balls, and hail - when concentric layers of ice in cumulonimbus clouds freeze, forming fairly large rounded pieces irregular shape, from 0.5 to 10 cm in diameter.

Precipitation. Thin clouds and clouds in the tropics do not reach freezing height, so ice crystals do not form in them (A). Instead, a larger-than-usual water particle in a cloud can combine with several million other water particles, resulting in the size of a raindrop. Electric charges can contribute to the association of water particles if they have opposite charges. Some of the droplets break apart, forming water particles large enough to start a chain reaction that creates a stream of raindrops. Most mid-latitude rainfall, however, is the result of falling snowflakes that melt before they reach the ground (B). Many millions of small water particles and ice crystals must combine to form a single drop or snowflake, heavy enough to fall from the cloud to the ground. However, a snowflake can grow from ice crystals in as little as 20 minutes. In order to form large hailstones, strong air currents (C) are required (hailstones with a diameter of 30 mm are formed at an air velocity of 100 km/h). Vortex air currents during a thunderstorm turn frozen water particles into initial hailstones. Abundant supercooled wet water particles easily freeze to its surface. The hailstone is thrown from side to side by air currents, as a result of which numerous dense layers of ice are concentrated on it, which can be transparent or white. An opaque layer is formed when air bubbles, and sometimes ice crystals, enter the hailstone during rapid freezing in the cold upper tiers of the cloud. Transparent layers form in the warmer lower layers of the cloud, where the water freezes much more slowly. There can be up to 25 or more layers (D) in a hailstone, with the last - a transparent layer of ice, often the thickest - formed when the hailstone falls through the moist and warm lower the edge of the cloud. The largest hailstone was registered on September 3, 1970 in Coffeeville, Kansas. Its diameter was 190 mm, and its weight was 766 g.

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Modern Encyclopedia

Atmospheric water in a liquid or solid state (rain, snow, grains, ground-based hydrometeors, etc.), falling out of clouds or deposited from the air on the earth's surface and on objects. Precipitation is measured by the thickness of the layer of precipitated water in mm. IN… … Big Encyclopedic Dictionary

Groats, snow, drizzle, hydrometeor, lotions, rain Dictionary of Russian synonyms. precipitation n., number of synonyms: 8 hydrometeor (6) ... Synonym dictionary

Precipitation- atmospheric, see Hydrometeors. Ecological encyclopedic dictionary. Chisinau: Main edition of the Moldavian Soviet encyclopedia. I.I. Grandpa. 1989. Precipitation water coming from the atmosphere to the earth's surface (in liquid or solid ... Ecological dictionary

Precipitation- atmospheric, water in a liquid or solid state, falling out of clouds (rain, snow, grain, hail) or deposited on the earth's surface and objects (dew, frost, hoarfrost) as a result of condensation of water vapor in the air. Precipitation is measured ... ... Illustrated Encyclopedic Dictionary

In geology, loose formations deposited in a suitable environment as a result of physical, chemical and biological processes ... Geological terms

PRECIPITATION, ov. Atmospheric moisture that falls to the ground in the form of rain or snow. Abundant, weak o. No precipitation today (no rain, no snow). | adj. sedimentary, oh, oh. Dictionary Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

- (meteor.). This name is used to denote the moisture that falls on the surface of the earth, being isolated from the air or from the soil in liquid or solid form. This release of moisture occurs every time water vapor is constantly ... ... Encyclopedia of Brockhaus and Efron

1) atmospheric water in a liquid or solid state, falling out of clouds or deposited from the air on the surface of the earth and on objects. O. falls out of the clouds in the form of rain, drizzle, snow, sleet, snow and ice pellets, snow grains, ... ... Emergencies Dictionary

PRECIPITATION- meteorological, liquid and solid bodies released from the air onto the surface of the soil and solid objects due to the condensation of water vapor contained in the atmosphere. If O. fall from a certain height, then hail and snow are obtained for rain; if they… … Big Medical Encyclopedia

Books

• Precipitation and thunderstorms from December 1870 to November 1871, A. Voeikov. Reproduced in the original author's spelling of the 1875 edition (publishing house `St. Petersburg`). IN…

In the understanding of the common man, precipitation Is it 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 which lead to beautiful effects. What kind of precipitation are there?

Rain

Rain is the fall of drops of water from the sky to the ground as a result of its condensation from the air. In the process of evaporation, water collects into clouds, which later turn into clouds. At a certain moment, the smallest droplets of steam increase, turning into the size of raindrops. Under their own weight, they fall to the surface of the earth.

Rains are heavy, torrential and drizzling. The continuous rain is observed for a long time, it is distinguished by a smooth beginning and end. The intensity of the fall of drops during the rain practically does not change.

Heavy rains are characterized by short duration and big size drops. They can reach five millimeters in diameter. A drizzle has drops less than 1 mm in diameter. It is practically 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 residue, since falling on a cold surface, snowflakes do not leave wet traces.

In most cases, heavy snowfalls develop gradually. They are characterized by smoothness and the absence of a sharp change in the intensity of precipitation. In a severe frost, the situation of the appearance of snow from a seemingly clear sky is possible. In this case, snowflakes are formed in the thinnest cloud layer, which is practically invisible to the eye. Such a snowfall is always very light, since a large snow load requires appropriate clouds.

Rain with snow

This is a classic type of precipitation in autumn and spring. It is characterized by the simultaneous fall of both raindrops and snowflakes. This happens due to small fluctuations in air temperature around 0 degrees. IN different layers the clouds get a different temperature, it also differs 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 called pieces of ice, into which, under certain conditions, water turns before falling to the ground. The size of the hailstones ranges from 2 to 50 millimeters. This phenomenon occurs in summer, when the air temperature is above +10 degrees and is accompanied by heavy rain with a thunderstorm. Large hailstones can cause damage to vehicles, vegetation, buildings and people.

snow grits

Snow groats are called dry precipitation in the form of dense frozen snow grains. They differ from ordinary snow in high density, small size (up to 4 millimeters) and almost round shape. Such croup appears at temperatures around 0 degrees, while it may be accompanied by rain or real snow.

Dew

Dew drops 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 the appearance of dew, a positive temperature, high humidity, and the absence of strong winds are required. Abundant dew can lead to water leaks on the surfaces of buildings, structures, and transport bodies.

Frost

This is winter dew. Hoarfrost is water that has condensed from the air, but at the same time the past stage of the liquid state. It looks like a lot of white crystals covering, as a rule, horizontal surfaces.

frost

It is a type of frost, but it does not appear on horizontal surfaces, but on thin and long objects. As a rule, hoarfrost in wet and frosty weather covers umbrella plants, wires of power lines, tree branches.

Ice

Icing is a layer of ice on any horizontal surfaces, which appears as a result of cooling fog, drizzle, rain or sleet with a subsequent drop in temperature in the range below 0 degrees. As a result of ice buildup, weak structures can collapse, and power lines can be torn.

Black ice is a special case of ice that forms only on the surface of the earth. Most often, it is formed after a thaw and a subsequent decrease in temperature.

ice needles

This is another type of precipitation, which is the smallest crystals floating in the air. Ice needles are perhaps one of the most beautiful winter atmospheric phenomena, as they often lead to different lighting effects. They are formed at air temperatures below -15 degrees and refract transmitted light in their structure. This results in halos around the sun, or beautiful "pillars" of light that extend from streetlights into clear, frosty skies.

Lately in different parts The globe is increasingly facing problems related to the amount and nature of precipitation. This year in Ukraine there was a very snowy winter, but at the same time, an unprecedented drought was observed in Australia. How does precipitation occur? What determines the nature of the fallout and many other issues are relevant and important today. Therefore, I chose the topic of my work "Formation and types of precipitation."

Thus, the main goal of this work is to study the formation and types of precipitation.

In the course of work, the following tasks are distinguished:

• Definition of the concept of precipitation
• Investigation of existing types of precipitation
• · Consideration of the problem and consequences of acid rain.

The main method of research in this work is the method of research and analysis of literary sources.

Atmospheric precipitation (Greek atmos - steam and Russian to precipitate - fall to the ground) - water in liquid (drizzle, rain) and solid (grain, snow, hail) form, falling out of clouds as a result of condensation of vapor rising in mainly from the oceans and seas (evaporated water from land is about 10% of precipitation). Precipitation also includes frost, hoarfrost, dew, deposited on the surface of terrestrial objects during the condensation of vapors in moisture-saturated air. Atmospheric precipitation is a link in the general moisture cycle of the Earth. With the onset of a warm front, heavy and drizzling rains are common, and with a cold front, showers. Atmospheric precipitation is measured using a precipitation gauge at meteorological stations with the thickness of the water layer (in mm) that fell during the day, month, year. The average amount of precipitation on the Earth is about 1000 mm/year, but less than 100 and even 50 mm/year falls in deserts, and in equatorial zone and on some windward slopes of the mountains - up to 12000 mm / year (Charranuja weather station at an altitude of 1300 m). Atmospheric precipitation is the main supplier of water to streams that feed the entire organic world into soils.

The main condition for the formation of precipitation is the cooling of warm air, leading to the condensation of the vapor contained in it.

When warm air rises and cools, clouds are formed, consisting of water droplets. Colliding in a cloud, the drops are connected, their mass increases. The bottom of the cloud turns blue and it rains. At negative air temperatures, water droplets in the clouds freeze and turn into snowflakes. Snowflakes stick together into flakes and fall to the ground. During a snowfall, they can melt a little, and then it snows. It happens that air currents repeatedly lower and raise frozen drops, at which time ice layers grow on them. Finally, the drops become so heavy that they fall to the ground like hail. Sometimes hailstones reach the size chicken egg. IN summer time in clear weather, the earth's surface cools. It cools the surface layers of air. Water vapor begins to condense on cold objects - leaves, grass, stones. This is how dew forms. If the surface temperature was negative, then the water droplets freeze, forming frost. Dew usually falls in summer, frost in spring and autumn. At the same time, both dew and frost can form only in clear weather. If the sky is covered with clouds, then the earth's surface cools slightly and cannot cool the air.

According to the method of formation, convective, frontal and orographic precipitation are distinguished. General condition precipitation is the upward movement of air and its cooling. In the first case, the reason for the rise of air is its heating from a warm surface (convection). Such precipitation falls all year round in the hot zone and in summer in temperate latitudes. If warm air rises when it interacts with colder air, then frontal precipitation is formed. They are more characteristic of temperate and cold zones, where warm and cold air masses are more common. The reason for the rise of warm air may be its collision with the mountains. In this case, orographic precipitation is formed. They are characteristic of the windward slopes of mountains, and the amount of precipitation on the slopes is greater than on the adjacent parts of the plains.

The amount of precipitation is measured in millimeters. On average per year for earth's surface about 1100 mm of precipitation falls.

Precipitation falling from clouds: rain, drizzle, hail, snow, grains.

Distinguish:

• heavy precipitation associated mainly with warm fronts;
• showers associated with cold fronts. Precipitation from the air: dew, frost, frost, ice. Precipitation is measured by the thickness of the layer of fallen water in millimeters. On average for the globe about 1000 mm of precipitation falls per year, and in deserts and at high latitudes - less than 250 mm per year.

Precipitation measurement is carried out by rain gauges, precipitation gauges, pluviographs at meteorological stations, and for large areas - with the help of radar.

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

The greatest amount of precipitation on the globe should be expected where atmospheric humidity is high and where there are conditions for raising and cooling the air. The amount of precipitation depends: 1) on latitude, 2) on general circulation atmosphere and related processes; 3) relief.

The greatest amount of precipitation both on land and on the sea falls near the equator, in the zone between 10 ° N. sh. and 10°S sh. Further north and south, precipitation decreases in the trade winds, with precipitation minima more or less coinciding with subtropical pressure maxima. At sea, precipitation minima are located closer to the equator than on land. However, the figures illustrating the amount of precipitation at sea cannot be particularly trusted due to the small number of observations.

From the subtropical pressure maxima and precipitation minima, the amount of these latter increases again and reaches a second maximum at approximately 40-50° latitudes, and from here decreases towards the poles.

A large amount of precipitation under the equator is explained by the fact that here, due to thermal causes, an area is created reduced pressure with ascending currents, air with a high content of water vapor (on average e = 25 mm), rising, cools and condenses moisture. The low rainfall in the trade winds is due to these last winds.

The lowest amount of precipitation observed in the area of ​​subtropical pressure maxima is explained by the fact that these areas are characterized by downward movement of air. As the air descends, it heats up and becomes dry. Further to the north and south, we enter the area of ​​prevailing southwestern and northwestern winds, i.e. winds moving from over warm countries to colder ones. Here, in addition, cyclones often occur, therefore, conditions are created that are favorable for raising the air and cooling it. All this entails an increase in precipitation.

As for the decrease in the amount of precipitation in the polar region, it must be borne in mind that they refer only to measured precipitation - rain, snow, croup, but frost deposition is not taken into account; meanwhile, it must be assumed that the formation of frost in polar countries, where, due to low temperatures relative humidity very large, occurs in large numbers. Indeed, some polar travelers observed that condensation occurs here mainly from the lower layers of air in contact with the surface in the form of hoarfrost or ice needles, settling on the surface of snow and ice and significantly increasing their power.

Relief has a huge influence on the amount of moisture falling out. Mountains, forcing the air to rise, cause its cooling and condensation of vapors.

One can especially clearly trace the dependence of the amount of precipitation on height in such settlements that are located on the slopes of the mountains, and their lower quarters are at sea level, and the upper ones are located quite high. Indeed, in each locality, depending on the totality of meteorological conditions, there is a certain zone, or height, at which the maximum condensation of vapor occurs, and above this zone the air becomes drier. So, on Mont Blanc, the zone of greatest condensation lies at an altitude of 2600 m, in the Himalayas on the southern slope - an average of 2400 m, in the Pamirs and Tibet - at an altitude of 4500 m. Even in the Sahara, mountains condense moisture.

By drop time maximum number rainfall all countries can be divided into two categories: 1) countries with prevailing summer and 2) countries with prevailing winter precipitation. The first category includes the tropical region, more continental regions of temperate latitudes and the northern margins of the land. northern hemisphere. Winter precipitation prevails in subtropical countries, then in the oceans and seas, as well as in countries with a maritime climate in temperate latitudes. In winter, the oceans and seas are warmer than the land, the pressure decreases, favorable conditions are created for the occurrence of cyclones and increased precipitation. We can establish the following divisions on the globe based on the distribution of precipitation.

Types of precipitation. Hail - called a special kind of ice formations that sometimes fall out of the atmosphere and are classified as precipitation, otherwise hydrometeors. The type, structure and size of hailstones are extremely diverse. One of the most common forms is conical or pyramidal with sharp or slightly truncated tops and a rounded base. The upper part of such is usually softer, matte, as if snowy; medium - translucent, consisting of concentric, alternating transparent and opaque layers; the lower one, the widest one, is transparent.

No less common is a spherical shape, consisting of an inner snow core (sometimes, although less often, the central part consists of clear ice) surrounded by one or more transparent shells. The phenomenon of hail is accompanied by a special characteristic noise from the impact of hailstones, reminiscent of the noise that comes from the spilling of nuts. Most of the hail falls during the summer and during the day. Hail at night is a very rare occurrence. It lasts several minutes, usually less than a quarter of an hour; but there are times when it lasts longer. The distribution of hail on earth depends on latitude, but mainly on local conditions. In tropical countries, hail is a very rare phenomenon, and there it falls almost only on high plateaus and mountains.

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. 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 out 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 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 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 that falls (most often at a 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.

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.

Fog is 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 mist do not differ. In fog, horizontal visibility is less than 1 km. Otherwise, haze is called haze.

Downpour - 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. Shower snow - snow of a shower character. 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") . Snow groats - 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 pellets - 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.

Dew (Latin 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.

Hoarfrost - loose ice crystals that grow on tree branches, wires and other objects, usually when drops of supercooled fog freeze. It is formed in winter, more often in quiet frosty weather as a result of sublimation of water vapor with a decrease in air temperature.

Hoarfrost is a thin layer of ice crystals that form on cold, clear and quiet nights on the surface of the earth, grasses and objects with a negative temperature, and lower than the air temperature. Frost crystals, like frost crystals, are formed by sublimation of water vapor.

Acid rain was first observed in Western Europe, in particular Scandinavia, and North America in the 1950s Now this problem exists throughout the industrial world and has acquired particular importance in connection with the increased technogenic emissions of sulfur and nitrogen oxides. precipitation acid rain

When power plants and industrial plants burn coal and oil, huge amounts of sulfur dioxide, particulate matter and nitrogen oxides are emitted from their stacks. In the United States, power plants and factories account for 90 to 95% of sulfur dioxide emissions. and 57% nitrogen oxides, with almost 60% sulfur dioxide emitted by tall pipes, which facilitates their transport over long distances.

As discharges of sulfur dioxide and nitric oxide from stationary sources are blown over long distances, they form secondary pollutants such as nitrogen dioxide, vapours. nitric acid and droplets containing solutions of sulfuric acid, sulfate and nitrate salts. These chemical substances fall on the earth's surface in the form of acid rain or snow, and also in the form of gases, veils, dew or solid particles. These gases can be directly absorbed by the foliage. The combination of dry and wet precipitation and the absorption of acids and acid-forming substances from near or on the earth's surface is called acid precipitation or acid rain. Another cause of acid rain is the release of nitric oxide to large numbers of cars in large cities. This type of pollution poses a threat to both urban and rural areas. After all, water droplets and most solid particles are quickly removed from the atmosphere, acid precipitation is more of a regional or continental problem than a global one.

Effects of acid rain:

• Damage to statues, buildings, metals and car trim.
• · Loss of fish, aquatic plants and microorganisms in lakes and rivers.
• Weakening or loss of trees, especially conifers that grow at high altitudes, due to leaching of calcium, sodium and other nutrients Damage to tree roots and loss of numerous fish species due to the release of aluminum, lead, mercury and cadmium ions from soils and milk precipitation
• · Weakening trees and increasing their susceptibility to diseases, insects, droughts, fungi and mosses that bloom in an acidic environment.
• · Decreased growth of crops such as tomatoes, soybeans, beans, tobacco, spinach, carrots, broccoli and cotton.

Acid precipitation is already a major problem in northern and central Europe, the northeastern United States, southeastern Canada, parts of China, Brazil and Nigeria. They are beginning to pose a growing threat in the industrial regions of Asia, Latin America and Africa and in some places in the western United States (mainly due to dry precipitation). Acid precipitation also falls into the ranks of tropical regions, where industry is practically not developed, mainly due to the release of nitrogen oxides during the combustion of biomass. Most of the acid-forming substances produced by a water country are transported by predominant surface winds to the territory of another. More than three-quarters of acid precipitation in Norway, Switzerland, Austria, Sweden, the Netherlands and Finland is brought to these countries by wind from the industrial regions of Western and Eastern Europe.

List of used literature

• 1. Akimova, T. A., Kuzmin, A. P., Khaskin, V. V., Ecology. Nature - Man - Technique: A textbook for universities. - M .: UNITI - DANA, 2001. - 343s.
• 2. Vronsky, V. A. acid rain: environmental aspect / / Biology at school. - 2006. - No. 3. - p. 3-6
• 3. Isaev, A. A. Ecological climatology. - 2nd ed. correct and additional .- M .: Scientific world, 2003.- 470s.
• 5. Nikolaykin, N. I., Nikolaykina N. E., Melekhova O. P. ecology. - 3rd ed. revised and additional .- M .: Bustard, 2004.- 624 p.
• 6. Novikov, Yu. V. Ecology, environment, people: Textbook.- M .: Grand: Fair - press, 2000.- 316s.

What is water vapor? What properties does it have?

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

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

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

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

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

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

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

Questions and tasks

1. How is precipitation formed?

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

2. Name the types of precipitation.

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

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

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

4. Why doesn't it always rain on cloudy days?

Precipitation occurs only when the air is saturated with moisture.

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

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

6. What is the annual rainfall in your area?

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

Precipitation 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 does a lot of damage 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 it falls exorbitantly. a large number of precipitation. 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.