What is precipitation types of precipitation. Atmospheric precipitation and phenomena

The atmosphere of our planet is constantly in motion - it is not for nothing that it is called the fifth ocean. In its thickness, movements of warm and cold air masses are observed - winds blow at different speeds and directions.


Sometimes the moisture in the atmosphere condenses and falls to the earth's surface in the form of rain or snow. Forecasters call it precipitation.

Scientific definition of precipitation

Precipitation in the scientific community is called ordinary water, which in liquid (rain) or solid (snow, hoarfrost, hail) form falls from the atmosphere to the surface of the Earth.

Precipitation can fall from clouds, which themselves are water condensed into tiny droplets, or form directly in air masses when two atmospheric flows with different temperatures collide.

Precipitation determines climatic features terrain, and also serves as the basis for crop yields. Therefore, meteorologists constantly measure how much precipitation fell in a particular area for a certain period. This information forms the basis of yields, etc.

Precipitation is measured in millimeters of the layer of water that would cover the surface of the earth if the water had not been absorbed and evaporated. On average, 1000 millimeters of precipitation falls per year, but some areas get more and others less.

So, in the Atacama Desert, only 3 mm of precipitation falls in a whole year, and in Tutunendo (Colombia) a layer of more than 11.3 meters of rainwater is collected per year.

Precipitation types

Meteorologists distinguish three main types of precipitation - rain, snow and hail. Rain is a drop of water in a liquid state, hail and - in a solid state. However, there are also transitional forms of precipitation:

- rain with snow - a frequent occurrence in autumn, when both snowflakes and drops of water alternately fall from the sky;

- freezing rain - enough rare view precipitation, which is ice balls filled with water. Falling to the ground, they break, the water flows out and immediately freezes, covering the asphalt, trees, roofs of houses, wires, etc. with a layer of ice;

- snow groats - small white balls, resembling groats, falling from the sky when the air temperature is close to zero. The balls consist of ice crystals slightly frozen together and are easily crushed in the fingers.

Precipitation can be torrential, continuous and drizzling.

- Heavy precipitation usually falls suddenly and is characterized by high intensity. They can last from several minutes to several days (in tropical climates), often accompanied by lightning and strong winds.

- Heavy precipitation falls for a long time, several hours or even days in a row. They begin with a weak intensity, gradually increase and then continue without changing the intensity, all the time until the end.

— Drizzling precipitation is very different from small size drops and those that fall not only from the clouds, but also from the fog. Quite often, drizzling precipitation is observed at the beginning and end of extensive precipitation, but can last for several hours or days as an independent phenomenon.

Precipitation formed on the surface of the earth

Some types of precipitation do not fall from above, but are formed directly in the lowest layer of the atmosphere in contact with the earth's surface. In the total amount of precipitation, they occupy a small percentage, but are also taken into account by meteorologists.

- Frost - ice crystals that freeze in the early morning on protruding objects and the ground surface if the night temperature drops below zero.

- Dew - drops of water that condense in the warm season as a result of night air cooling. Dew falls on plants, protruding objects, stones, walls of houses, etc.

- Rime - ice crystals that form in winter at a temperature of -10 to -15 degrees on tree branches, wires in the form of fluffy fringe. Appears at night and disappears during the day.

- Icing and ice - freezing of the ice layer on the surface of the earth, trees, walls of buildings, etc. as a result of rapid air cooling during or after sleet and freezing rain.


All types precipitation formed as a result of the condensation of water evaporated from the surface of the planet. The most powerful "source" of precipitation is the surface of the seas and oceans, land gives no more than 14% of all atmospheric moisture.

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, different kinds 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 physical and chemical properties water and its ability to be in three states of aggregation - liquid, solid and vapor (3 types of precipitation).

At school, this topic is taught in the 2nd grade in the subject "World around".

What is precipitation

A strict definition of precipitation in geography is usually given as follows. This term refers to such phenomena that occur in the Earth's atmosphere, which are based on the concentration of water in the air layer, and are also associated with the transition of water dispersion to various states of aggregation and precipitation on the surface of the planet.

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

• obligatory– associated with warm air currents;
• storm associated with cold air masses.

To account for the amount of precipitation that falls on the Earth's surface in a certain region, meteorologists use special equipment - rain gauges, which provide data measured in the thickness of the layer of liquid water that has fallen on a solid surface. The units of measurement are millimeters per year.

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

Types of precipitation

It is possible to conditionally divide the types of precipitation on the basis of the state of aggregation of water in which it enters the Earth. In principle, this is possible in only two versions - solid and liquid form.

Based on this, the classification is as follows:

• liquid- (rain and dew);
• solid- (snow, hail and frost).

Let's figure out what each type of such precipitation represents.

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

Getting into the upper layers of the atmosphere, which are noticeably colder, water condenses, forming a cluster of tiny droplets. As soon as the amount of condensate reaches a large mass, the water spills onto the ground in the form of heavy rain.

Types of rain are classified according to the size of the drops, which in turn is related to the currents and air temperature.

A variety of rains is formed as follows - if the air is warm, then it forms larger drops, and if it is cold, then drizzling light rain (supercooled rain) can be observed. When the temperature drops, it rains with snow.

Another process related to condensation is dew drop. This physical phenomenon is based on the fact that in a certain volume of air there can be a strictly defined amount of steam at a given temperature.

Until the limiting volume of vapor is reached, condensation does not occur, but as soon as the amount exceeds the desired value, the excess precipitates into a liquid state. We can observe this in the early morning on the street, looking at the dew, flowers and other solid objects.

Another common type of precipitation is snow. In principle, its formation is similar to the formation of rain, however, rain differs from snow in that when it falls on the ground, the drops are significantly cooled by air jets that have a negative temperature, and microscopic ice crystals form.

Since the process of formation of snowflakes occurs in the air and under the influence of different temperatures, this causes a large number of shapes and crystals of snowflakes.

If the temperature is very low, then blanket snow forms, if it is closer to zero, then heavy snow. Wet snow forms at temperatures slightly above freezing.

One of the dangerous atmospheric phenomena- This deg. Its formation occurs mainly in summer, when heated air flows carry vaporous moisture to the upper layers of the atmosphere, where, supercooling, the water freezes, forming ice pieces.

They do not have time to melt when flying before earth's surface and are often the cause of crop destruction or damage to buildings.

Condensation of water from steam is also possible in winter. This is mainly due to the very low relative humidity of the air.

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

Types of precipitation by seasons of the year

Often a characteristic based on the seasonality of precipitation is used.

So, there are:

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

Types of precipitation by formation height

More accurate is the classification, which takes into account at what height the condensate turned into one of the types of precipitation:

• precipitation that forms in the upper and middle layers of the atmosphere includes rain, drizzle, hail, grains and snow - falling from clouds;
• Precipitation that forms in the immediate vicinity of the earth's surface (orographic precipitation) includes mainly condensation phenomena (examples - dew, hoarfrost, frost and ice) - falling out of the air.

How precipitation is measured

Often in the weather forecast you can hear that 2 millimeters of precipitation fell per day. Such data are determined by meteorologists and weather forecasters at weather stations using special equipment - precipitation gauges.

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

Every day, in the time interval from 9-00 to 21-00 (time is taken according to the GMT 0 time zone), the meteorologist collects all the moisture that accumulates in the bucket and pours it into a graduated cylinder (cylinder divisions are made in mm).

The obtained values ​​are recorded in the log book, forming a table of precipitation. If the precipitates were solid, then it is allowed to melt them.

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

How precipitation affects aviation operations

There are a number of very important atmospheric factors that hinder the operation of aviation. First of all, it is connected with ensuring flight safety.

The main ones are:

1. First of all, this is a deterioration in visibility for aircraft pilots. The decrease in visibility in heavy rain or a snowstorm occurs up to 1.5-2 km, which makes it difficult to visually control the course.
2. During takeoff or landing, moisture condensation on windows or optical reflectors can lead to a distorted perception of information by the pilot.
3. A large amount of water fine dust, if it enters the engine, can make it difficult and disrupt its operation.
4. When the aerodynamic elements of the aircraft (wings, steering elements) are iced, there is a loss of flight characteristics.
5. When a significant amount of precipitation falls, contact with the runway coating is difficult.

Thus, all precipitation, in relation to aviation, is extremely unfavorable.

Precipitation is a key factor contributing to the formation of the Earth's climate, as well as geographical areas. Conditional division is carried out depending on seasonality, however, it should be remembered that combinations can occur in the off-season. Also, precipitation is essential element water circulation on the planet.

Not every cloud carries precipitation, because for the formation of both prerequisite is the presence of water in three states: gaseous, liquid and solid, characteristic of mixed clouds. Precipitation occurs only when the cloud begins to rise higher and cool. By origin, precipitation is divided into the following types: convective, frontal and orographic.

Convective type of precipitation It is typical for hot climatic zones, in which intense heating takes place throughout the year, as a result of which water evaporates. At this time, the ascending movement of moist and warm air prevails. Such processes can be observed in summer in temperate zones.

Frontal precipitation are formed in the event of a meeting of two air masses of different temperatures and other factors. Frontal precipitation is observed in the temperate and cold zones.

Orographic precipitation characteristic of windward mountain slopes, forcing the air to rise higher. With the loss of moisture, the air descends, bypassing the mountain range, but after it warms up, and relative humidity moves away from saturation.

According to the nature of precipitation, precipitation is divided into showers (short, but intense precipitation over a small area), overcast (long-term and uniform precipitation of medium intensity, covering a rather large area) and drizzling (they are characterized by small and small rainfall).

Measuring the amount of precipitation.

Precipitation determined by measuring the thickness of a millimeter layer of water formed as a result of their falling onto a horizontal surface and further infiltration into the soil. In order to measure the amount of precipitation, a metal cylinder with a diaphragm installed is used - a rain gauge, as well as a rain gauge with special protection. Precipitation of the solid type is preliminarily melted, and the resulting amount of water is measured by a cylindrical vessel, the bottom area of ​​which is ten times smaller than the bottom of the rain gauge. When the layer of water in the vessel reaches a figure of 20 mm, this will mean that the layer that has fallen to the Earth is 2 m 2 mm in height.

• 1 - Rain gauge installed on the meteorological platform for measuring liquid precipitation;
• 2 - Soil rain gauge, dug in flush with the ground, there is also a bucket installed inside to collect precipitation;
• 3 - Field rain gauge - a glass tall glass with divisions, for assessing precipitation in agricultural fields;
• 4 - Rain gauge - for collecting liquid and solid precipitation(snow, cereals ...);
• 5 - Pluviograph - recorder of the amount of liquid precipitation;
• 6 - Total precipitation gauge - for collecting precipitation over a long period (a week, 10 days, ...) in hard-to-reach places;
• 7 - Radio rain gauge.

All measurements are taken into account for a specific month to derive monthly indicators, and subsequently annual ones. The longer the observation, the more accurate the calculation will be. rainfall for different time intervals for a particular observation site. Those lines on the map, the points of which are connected with the same amount of precipitation in millimeters, are called isohyets and indicate the amount of precipitation for a certain period of time (for example, for a year).

Distribution of precipitation on the Earth's surface.

On geographical position precipitation on the earth's surface is influenced by many factors: temperature, evaporation, humidity, cloud cover, atmospheric pressure, ocean currents, wind, and the location of land and sea. Temperature is the dominant factor, as it affects the rate of evaporation and the amount of moisture.

In cold latitudes, the level of evaporation is negligible, since the air in these latitudes contains very little water vapor. Even though the relative humidity can be quite high, there will be little precipitation in any case when the steam condenses. In warm regions, the opposite situation is observed, in which, with a large level of evaporation, there is a huge rainfall. That is why precipitation is usually distributed zonal.

The greatest amount of precipitation (1000-2000 mm and more) is observed in equatorial belt, where year-round high temperatures, high evaporation and the predominance of ascending air currents.

In tropical latitudes rainfall less - from 300 to 500 mm, and in desert continental areas less than 100 mm. The reason for this was the dominance of high pressure in combination with downdrafts. The eastern coasts, which are washed by warm currents, are characterized by a large amount of precipitation, especially in summer.

In temperate latitudes, the amount of precipitation increases to 500-1000 mm and the greatest amount of precipitation falls on the western coasts, with prevailing western winds from the oceans. Huge rainfall also caused by warm currents and the presence of mountainous terrain.

In the polar zones, the amount of precipitation is quite low - from 100 to 200 mm. This is due to low humidity in the air, but with a lot of cloudiness.

The amount of precipitation does not always determine the conditions of moisture. The nature of moisture is expressed using the moisture coefficient - the ratio of precipitation to evaporation for the same period - K \u003d O / B, where is the moisture coefficient, O is the annual amount of precipitation, and B is the evaporation value. If K=1, then moisture is sufficient, if more - excessive, and if less - insufficient. Humidification implies one type or another natural areas: with excessive and sufficient moisture, forests can grow, insufficient and close to unity moisture is typical for forest-steppes and savannahs, low and closer to zero indicators imply steppes, deserts and semi-deserts.

Precipitation is commonly 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 meteorological radars, which allow measuring different types rainfall over a large area.

On average, the planet receives about a thousand millimeters of precipitation per year. All of them are not evenly distributed over the Earth. The exact level depends on the weather, terrain, climate zone, proximity to water bodies and other indicators.

What are the precipitation

From the atmosphere, water enters the earth's surface in two states: liquid and solid. Because of this feature, all types of precipitation are divided into:

1. Liquid. These include rain, dew.
2. Solid ones are snow, hail, frost.

There is a classification of precipitation types according to their shape. So they emit rain with drops of 0.5 mm or more. Anything less than 0.5 mm refers to drizzle. Snow is ice crystals with six corners, but round solid precipitation is grits. It is a round-shaped core of different diameters, which are easily compressed in the hand. Most often, such precipitation falls at temperatures close to zero.

Of great interest to scientists is hail and ice pellets. These two types of sediment are difficult to crush with your fingers. The croup has an icy surface, when it falls, it hits the ground and bounces off. Hail - large ice, which can reach a diameter of eight or more centimeters. This type of precipitation usually forms in cumulonimbus clouds.

Other types

The smallest type of precipitation is dew. These are the smallest droplets of water that form in the process of condensation on the surface of the soil. When they come together, dew can be seen 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, then a thin layer of ice crystals or frost appears.

In weather forecasting, precipitation is most often understood as rain and snow. However, not only these species are included in the concept of precipitation. This also includes liquid plaque, which is formed in the form of water droplets or in the form of a continuous water film in cloudy, windy weather. This type of precipitation is observed on the vertical surface of cold objects. At sub-zero temperatures, the plaque becomes solid, most often thin ice is observed.

The loose white deposit that forms on wires, ships, and more is called frost. This phenomenon is observed in foggy frosty weather with light wind. Hoarfrost can quickly build up, breaking wires, light ship equipment.

Freezing rain is another one unusual view. It occurs at negative temperatures, most often from -10 to -15 degrees. This species has some peculiarity: the drops look like balls covered with ice on the outside. When they fall, their shell breaks, and the water inside is sprayed. Under the influence of negative temperatures, it freezes, forming ice.

The classification of precipitation is also carried out according to other criteria. They are divided according to the nature of the fallout, by origin and not only.

The nature of the fallout

According to this qualification, all precipitation is divided into drizzling, torrential, overcast. The latter are intense, uniform rains that can last for a long time - a day or longer. This phenomenon covers quite large areas.

Drizzling precipitation falls in small areas and is small drops of water. Heavy rain refers to heavy rainfall. It goes intensively, not for long, captures a small area.

Origin

By origin, there are frontal, orographic and convective precipitation.

Orographic fall on the slopes of the mountains. They are most abundant if warm air of 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 observe precipitation, their amount, pointing to climate maps their intensity. So, if you look at annual maps, you can trace the unevenness of precipitation around the world. It rains most intensively in the Amazon region, but in the Sahara desert there is little rainfall.

The unevenness is explained by the fact that precipitation brings moist air masses that form over the oceans. This is most clearly seen in the territory with a monsoonal climate. Most moisture comes from summer time with the monsoons. Over land, there are prolonged rains, such as on the Pacific coast in Europe.

Winds play an important role. Blowing from the continent, they carry dry air to the northern territories of Africa, where the world's largest desert is located. And in the countries of Europe, the winds carry rain from the Atlantic.

Precipitation in the form of heavy rains is influenced by sea currents. Warm contributes to their appearance, and cold, on the contrary, prevents them.

The terrain plays an important role. The Himalayan mountains do not allow wet winds from the ocean to pass north, which is why up to 20 thousand millimeters of precipitation falls on their slopes, and on the other hand, they practically do not happen.

Scientists have found that there is a relationship between atmospheric pressure and the amount of precipitation. On the territory of the equator in the belt low pressure the air is constantly heated, it forms clouds and heavy rains. A large amount of precipitation occurs in other areas of the Earth. However, where the air temperature is low, precipitation is not often in the form of freezing rain and snow.

Fixed data

Scientists are constantly recording rainfall around the world. the globe. Most of the precipitation is recorded in the Hawaiian Islands, located in pacific ocean, in India. Over 11,000 millimeters of rain fell in these territories during the year. The minimum is registered in the Libyan desert and in Atakami - less than 45 millimeters per year, sometimes in these territories there is no precipitation at all for several years.

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- this is water that has fallen 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 evaporation occurs a large number moisture. 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.