Wind formation

Although the air is invisible to the eye, we always feel its movement - the wind. The main cause of the occurrence of wind is the difference in atmospheric pressure over parts of the earth's surface. As soon as the pressure decreases or increases somewhere, the air will go from the place of greater pressure to the direction of less. And the pressure balance is disturbed by the unequal heating of various parts of the earth's surface, from which the air heats up differently.

Let's try to imagine how this happens on the example of the wind that occurs on the coasts of the seas and is called a breeze. Land plots - land and water - are heated differently. Sukhodol heats up faster. Therefore, the air above it heats up faster. It rises, the pressure decreases. Above the sea at this time, the air is colder and accordingly higher pressure. Therefore, air from the sea moves to land in place of warm. So the wind blew - daytime breeze. At night, everything happens the other way around: dry land cools faster than water. Above it, cold air creates more pressure. And above water, it retains heat for a long time and cools slowly, the pressure will be lower. Cold air from land from the high-pressure area moves towards the sea, where the pressure is less. Arises night breeze.

Therefore, the difference in atmospheric pressure acts as a force, causing horizontal movement of air from the high-pressure region to the low-pressure region. So the wind is born.

Determining wind direction and speed

The direction of the wind is determined beyond the side of the horizon from where it blows. If, for example, the wind blows from an event, it is called western. This means that air moves from west to east.

Wind speed depends on atmospheric pressure: the greater the difference in pressure between parts of the earth's surface, the stronger the wind. It is measured in meters per second. At the earth's surface, winds often blow at a speed of 4-8 m / s. In ancient times, when there were no devices yet, wind speed and strength were determined by local signs: in the sea - due to the effect of wind on water and ship sails, on land - from the tops of trees, smoke deviation from pipes. For many reasons, a 12-point scale was developed. It allows you to determine the strength of the wind in points, and then its speed. If there is no wind, there is its strength and speed equal to zero, then this calm. 1 point wind, barely swaying the leaves of trees, called quiet. Next on the scale: 4 points - moderate wind (5 m / s), 6 points - strong wind (10 m / s), 9 points - storm (18 m / s), 12 points - hurricane (Over 29 m / s). At weather stations, the strength and direction of the wind is determined using weather vaneand speed anemometer.

The strongest winds near the Earth's surface are blowing in Antarctica: 87 m / s (individual gusts reached 90 m / s). The highest wind speed in Ukraine was recorded in Crimea at woe - 50 m / s.

Monsoon - periodic wind carrying a large number of moisture blowing in winter from land to ocean, in summer from ocean to land. Monsoons are observed mainly in the tropical zone. Monsoons are seasonal winds that last several months of every year in tropical areas. This term originated in British India and surrounding countries as the name for seasonal winds that blow from the Indian Ocean and Arabian sea to the northeast, bringing significant rainfall to the region. Their movement towards the poles is caused by the formation of low pressure areas as a result of heating of the tropical areas in the summer months, that is, Asia, Africa and North America from May to July and in Australia in December.

Trade winds - constant windsblowing with a fairly constant force of three to four points; their direction practically does not change, only slightly deviating. The trade winds are the near-surface part of the Hadley cell - the predominant near-surface winds that blow in the tropical regions of the Earth in a westerly direction, approaching the equator, that is, northeast winds in the Northern Hemisphere, and southeast winds in the South. The constant movement of the trade winds leads to the mixing of the Earth’s air masses, which can manifest itself on a large scale: for example, trade winds blowing over the Atlantic Ocean are able to carry dust from the African deserts to the West Indies and parts of North America.

Local winds:

Breeze - a warm wind blowing from shore to sea at night and from sea to shore during the day; in the first case it is called the coastal breeze, and in the second - the sea. Important effects of the formation of predominant winds in coastal areas are sea and continental breezes. The sea (or a smaller body of water) heats more slowly than land due to the greater heat capacity of the water. Warmer (and therefore lighter) air rises above the land, creating zones of reduced pressure. The result is a pressure differential between land and sea, which is usually 0.002 atm. Due to this pressure drop, cool air above the sea moves to land, creating a cool sea breeze on the coast. Due to the lack of stronger winds, the speed of the sea breeze is proportional to the temperature difference. If there is wind from the land side at a speed of more than 4 m / s, the sea breeze usually does not form.

At night, due to its lower heat capacity, the land cools faster than the sea, and the sea breeze stops. When the land temperature drops below the surface temperature of the reservoir, a reverse pressure drop occurs, causing (in the absence of a strong wind from the sea) a continental breeze that blows from land to sea.

Bora - cold harsh wind blowing from the mountains to the coast or valley.

Fönn - a strong warm and dry wind blowing from the mountains to the coast or valley.

Cirocco is the Italian name for the strong south or southwest wind originating in the Sahara.

Variable and constant winds

Variable winds change their direction. These are the spray you already know (with the French "Breeze" - a light breeze). They change their direction twice a day (Day and night). Spray occurs not only on the coasts of the seas, but also on the shores of large lakes and rivers. However, they cover only a narrow strip of the coast, penetrating deep into the land or sea for several kilometers.

Monsoon are formed in the same way as breezes. But they change their direction twice a year according to the seasons (summer and winter). Translated from Arabic, "monsoon" means "Season". In summer, when the air over the ocean heats up slowly and the pressure over it is higher, moist sea air penetrates the land. This is a summer monsoon that carries daily thunderstorms. And in winter, when high air pressure is set above land, the winter monsoon begins to act. It blows from land towards the ocean and brings cold, dry weather. So, the reason for the formation of monsoons is not daily, but seasonal fluctuations in air temperature and atmospheric pressure over the mainland and the ocean. Monsoons penetrate land and ocean for hundreds and thousands of kilometers. They are especially common on the southeast coast of Eurasia.

Unlike variables, constant winds blow in one direction throughout the year. Their formation is associated with high and low pressure belts on Earth.

Trade winds - Winds that blow throughout the year from high pressure belts near the 30 tropical latitudes of each hemisphere to a low pressure belt at the equator. Under the influence of the Earth's rotation around its axis, they are directed not directly to the equator, but deviate and blow from the northeast in the Northern Hemisphere and from the southeast to the South. The trade winds, characterized by uniform speed and amazing constancy, were the seafarers' favorite winds.

From tropical belts high pressure winds blow not only to the equator, but also in the opposite direction - to the 60th latitudes with low pressure. Under the influence of the deflecting force of the Earth's rotation with distance from tropical latitudes, they gradually deviate to the east. So there is a movement of air from west to east and these winds in temperate latitudes become western.

SECTION 3 GEOGRAPHICAL SHELL

Theme 2. Atmosphere

§ 36. Wind. Constant and variable winds

Remember

How do you watch the wind?

Which winds prevail in your area?

Wind is the movement of air in a horizontal or close direction. In this case, air moves from a zone of high atmospheric pressure to an area with low atmospheric pressure. Wind is characterized by speed, strength and direction. Wind speed is measured in meters per second (m / s) or in kilometers per hour (km / h). To convert meters per second to kilometers per hour, you need to multiply the speed in meters per second by 3.6.

The strength of the wind is determined by the pressure of moving air on objects. It is measured in kilograms per square meter (kg / m2). The strength of the wind depends on its speed. So, the wind at a speed of 100 km / h has a force 10 times greater than at a speed of 10 km / h. The greater the difference in atmospheric pressure, the stronger and faster the wind blows. The absence of any signs of wind is called calm.

Modern Facts

The strongest winds. Outlying parts of Antarctica, where the winds blow for 340 days a year, are considered the “pole of winds" on Earth. The highest wind speed - 371 km / h - was recorded in 1934 in the United States, on a mountain in the state of New Hampshire. In Ukraine, the strongest wind was in the city of Ai-Petri in the Crimea (its speed reached 180 km / h).

The direction of the wind is determined by the position of that side of the horizon from where it blows. To indicate the direction of the wind in practice, the horizon is divided into eight directions. Of these, four head - North (Mon), South (South), East (Cx) and West (W) and four intermediate - North-East (North-East), North-West (North-West), South-East Front-Cx) and southwestern (Front-Zx).

For example, when the wind blows from a location located between the south and east, it is called southeastern (PD-Cx). The direction and speed of the wind is determined using a weather vane (Fig. 97). A clear idea of \u200b\u200bthe directions of the winds that prevail in a given area is given by a special diagram - a rose of winds (Fig. 98). This is a graphical representation of the repeatability of wind directions. The length of its rays is proportional to the frequency of winds in a given direction.

Fig. 97. Weather vane

PRACTICAL WORK No. 8(continued)

Weather Observations: composing a wind rose

Using the data in the table, build a wind rose. To do this, first draw the coordinates, indicating four wind directions and four intermediate. At the scale of your choice, set aside the number of lines corresponding to each direction. The ends of the segments are connected in series. Paint the resulting wind rose and indicate which direction the wind prevailed. In Figure 98, note how the winds of various directions denote.

Fig. 98. Wind rose

Constant and variable winds. On the the globe there is not a single windless place. There are many different types of winds. There are winds that blow constantly, and there are those that change their direction during the day or year. Permanent winds - trade winds - arise between the high tropical and equatorial low zones of atmospheric pressure in the Northern and Southern hemispheres of the Earth (Fig. 99). Due to the rotation of the globe, trade winds in the Northern Hemisphere are moving from the northeast to the southwest, and in the South from the southeast to the northwest. The trade winds hardly change their direction during the year. their speed is on average 5-6 m / s, and the vertical thickness reaches 2-4 km and increases towards the equator.

In temperate latitudes, westerly winds blow. They are also permanent.

Fig. 99. The trade winds

Fig. 100. Education day (a) and night (b) breeze

There are much more variable winds on the globe than constant ones. Distributed only in certain territories, they are called local.

Local winds blow over a relatively small area (from hundreds of meters to tens of kilometers) and significantly affect the weather in this area. An example of a local breeze wind. Translated from French, this word means "a breeze." Its speed is really insignificant - up to 4 m / s. The breeze blows with daily intervals on the coast of the seas, large lakes and some large rivers. This wind changes direction twice a day, which is caused by uneven heating of the land surface and the reservoir. The daytime, or sea, breeze moves from the water surface to land, and the night, or coastal, moves from the chilled coast of land to the body of water (Fig. 100).

The breeze occurs mainly in the summer, when the temperature difference between land and water reaches its highest value. In Ukraine, breezes are observed on the coast of reservoirs, the Black and Azov Seas.

Amazing phenomena

Wind from the mountain peaks.

Interesting local winds are fiones, which do not have a certain periodicity. They are not constant and last on average from one to two days.

Fion is a strong, gusty, dry and warm wind blowing from mountain peaks into valleys. It arises when air passes over the crest of a mountain range and, descending the slope, quickly heats up (Fig. 101). In this case, the temperature can reach maximum values for a given time of the year. So, with a strong fion on the icy island of Greenland, the temperature rises by 20-25 ° C. The fion causes snowmelt in the mountains in winter, and droughts and fires in summer. In the mountainous regions of Ukraine, fiones, which blow from the southeastern slopes of the Crimean mountains near Alushta, can suddenly raise the temperature here to 28 ° С. Fioni in the Ukrainian Carpathians have a speed of up to 25 m / s.

Fig. 101. Education fionov

Fig. 102. The movement of monsoons

To the winds that change their direction, include the monsoon. The word "monsoon" is translated from Arabic as "season". This name is not accidental, because the monsoon changes its direction twice a year: in winter it blows from land to ocean, and in summer, on the contrary, from ocean to land (Fig. 102). (Think about why the monsoon changes direction in the seasons.) Monsoon winds are best expressed in the south and east of Asia, in the north of the Indian and in the west of the Pacific Ocean. Especially powerful is the Asian summer monsoon. It contains a large amount of moisture and heat, and heavy rainfall is associated with it.

Wind is the horizontal movement of air, resulting from the difference in atmospheric pressure.

Wind is characterized by speed, strength and direction.

Constant winds blow constantly, variable winds change their direction during the day or year.

Questions and tasks for self-testing

Build a wind rose from your observations. Explain which winds prevail in your area. Schematically draw the direction of the wind according to the following data: a) the pressure in point A is 760 mm Hg. Art., and in paragraph B - 784 mm RT. st .; b) on the coast, the pressure is 758 mm Hg. Art., and above the lake - 752 mm RT. Art. In which case will the wind be stronger?

Choose from the listed winds one that almost does not change its direction: a) trade wind; b) monsoon c) breeze.

What is the cause of the wind? What determines the strength and speed of the wind?

The wind is one of the most unique natural phenomena. We cannot see it, touch it, but we are able to observe the results of its manifestation, for example, how it slowly or quickly drives clouds and clouds through the sky, tilts trees to the ground with its force, or slightly rubs foliage.

Wind concept

What is the wind? The definition from the point of view of meteorology is as follows: this is the horizontal movement of layers of air from a zone with high atmospheric pressure to a zone of low, accompanied by a certain speed. This movement occurs because during the day the sun penetrates the air layer of the Earth. Some rays, reaching the surface, heat the oceans, seas, rivers, mountains, soil, rocks and stones that give off heat to the air, thereby heating it. For the same amount of time, dark objects absorb more heat and get warmer.

But what does it matter how heat is given off and how fast? And how does this help us figure out what the wind is? The definition is as follows: the land heats faster than water, which means that the air accumulated above it receives heat from it and rises, therefore, the atmospheric pressure above this section drops. With water, everything is exactly the opposite: above it, the air masses are colder and the pressure is higher. As a result, cold air is displaced from the high-pressure section to the low-pressure section, forming a wind. The larger the difference between these pressures, the stronger it is.

Types of winds

Having figured out what the wind is, you need to find out how many species there are and how they differ from each other. There are three main groups of winds:

• local
• permanent
• regional.

Local winds correspond to their name and blow only in certain areas of our planet. Their appearance is associated with the specifics of local reliefs and temperature changes in relatively short intervals. These winds are characterized by short length and daily frequency.

What is the wind of local origin, it is now clear, but it is divided into its subspecies:

• A breeze is a light breeze that changes direction twice a day. During the day, it blows from the sea to land, and vice versa at night.
• Bora is a high-speed cold air stream blowing from the tops of mountains to valleys or coasts. He is fickle.
• Foehn is a warm and light spring wind.
• Dry wind - a dry wind prevailing in the steppe regions during the warm period under conditions of an anticyclone. He portends a drought.
• Sirocco - the rapid southern, southwest air currents that form in the Sahara.
• And what is the hamsin wind? These are dusty, dry and hot air masses prevailing in northeast Africa and the east of the Mediterranean.

Permanent winds include those that depend on the total air circulation. They are stable, uniform, permanent and strong. They include:

• trade winds - winds from the east, differ in constancy, not changing direction and strength of 3-4 points;
• anti-trade winds - winds from the west, carrying huge air masses.

Regional wind appears as a result of pressure drops, a bit like a local one, but more stable and powerful. Bright representative This species is considered a monsoon, which originates in the tropics, at the turn of the ocean. It blows periodically, but with large-scale flows, changing its direction a couple of times a year: in the summer season - from water to land, in the winter - vice versa. Monsoon brings a lot of moisture in the form of rains.

A strong wind is ...

What is a strong wind and how does it differ from other streams? Its main feature is its high speed, which ranges from 14-32 m / s. It produces devastating actions or brings damage, destruction. In addition to speed, temperature, direction, location and duration also matter.

Types of Strong Winds

• A typhoon (hurricane) is accompanied by intense rainfall and a drop in temperature, great strength, speed (177 km / h or more), blowing at a distance of 20-200 m for several days.
• What is a wind called a flurry? This is a sharp, sudden stream at a speed of 72-108 km / h, formed in the hot period as a result of the powerful penetration of cold air into the warm zone. It blows for a couple of seconds or tens of minutes, changing direction, and brings a decrease in temperature.
• Storm: its speed is 103-120 km / h. It is characterized by high duration, strength. It is a source of strong sea oscillations and destruction on the earth.

• Tornado (tornado) is an air vortex visually resembling a dark pillar along which a curved axis passes. At the bottom and top of the column there are extensions similar to a funnel. The air in a whirlwind rotates counterclockwise at a speed of 300 km / h and draws all nearby objects and objects into its funnel. The pressure inside the tornado is reduced. The pillar reaches a height of 1,500 m, and its diameter is from a dozen (above water) to hundreds of meters (above the ground). A tornado can go from a couple of hundred meters to tens of kilometers at a speed of 60 km / h.
• A storm is an air mass whose speed is in the range of 62-100 km / h. Storms abundantly cover the area with sand, dust, snow, earth, causing harm to people and the household.

Description of wind power

Answering the question of what wind power is, it will be appropriate to note that here the concept of force is interconnected with speed: the higher it is, the stronger the wind. This indicator is measured on a 13-point Beaufort scale. Zero value characterizes calm, 3 points - light, weak wind, 7 - powerful, 9 - the appearance of a storm, over nine - merciless storms, hurricanes. Strong winds often blow over the sea, the ocean, because nothing prevents them here, unlike rocky mountains, hills, forests.

Solar wind definition

What is a solar wind? This is an amazing phenomenon. Ionized plasma particles flow from the solar corona (outer layer) into space with a speed range of 300-1200 km / s, which depends on the activity of the Sun.

There are slow (400 km / s), fast (700 km / s), high-speed (up to 1200 km / s) solar winds. They form a region with a space around the central celestial body that protects the solar system from interstellar gas entering it. In addition, thanks to them, such phenomena as the radiation belt and aurora occur on our planet. This is what the solar wind is.

Name the constant winds above the earth's surface and explain their formation. and got the best answer

Reply from исaisiyaKonovalova [guru]
trade winds, monsoons, breezes.

Answer from 2 answers[guru]

Hello! Here is a selection of topics with answers to your question: Name the constant winds above the earth's surface and explain their formation.

Answer from Ѓrazaeva Tamila[newbie]
At some latitudes of the Earth there are high and low pressure belts. For example, atmospheric pressure is lower above the equator because the earth's surface there is very hot. Strong global winds, called Westerly winds and trade winds, are blowing from the high pressure belts towards the low pressure belts. However, they do not move directly from south to north and from north to south. This is due to the fact that the rotation of the Earth forces global winds to turn to the side.

Answer from DEMENKOVA AVATARIA[newbie]
about

Answer from Kazimagomed Hajibeyov[master]
google to help .. but in general this is an easy question ... topic is 6th grade.

Answer from skyrim skairim[newbie]
trade winds, monsoons, breezes.
The trade winds are formed due to the pressure drop in the tropical regions of both hemispheres and at the equator. These winds are deflected by the rotation of the Earth: the trade winds of the northern hemisphere blow from the northeast to the southwest, and the trade winds of the south - from the southeast to northwest. They are quite stable in temperature and humidity and are one of the most important factors in climate formation.
Monsoons are formed due to pressure drops resulting from temperature differences. A distinctive feature of monsoons is that in the warm and cold season they are directed in opposite directions: from sea to land and from land to sea. In winter, air is warmer above the sea than above land, atmospheric pressure above the sea is lower, therefore, monsoons are directed from land to sea. In the warm season, the opposite is true: the air is warmer over land, a low pressure region forms there. Monsoons at this time blow to land and bring with them heavy rainfall.
In the tropical zone, monsoons are especially active, but they exist outside the tropics. Areas dominated by monsoons are characterized by very humid summers. A great example of the influence of monsoons is India, where the Himalayan mountains are stopped by a humid wind, so in northern India, Burma, Nepal there is a huge amount of rainfall.
Breezes, like monsoons, change their direction to the opposite, but this happens with a frequency of one day. These are not very large-scale winds, they are formed near the seas, oceans, large lakes, rivers. In the afternoon, air over land heats up, warm air rises, and in its place comes cooler, with water. At night, on the contrary, it is warmer above the water; colder air masses come here from land. Thus, a breeze blows from water to land during the day, and from land to water at night.

Education local winds due to the nature of the underlying surface (orography, surface type - water or land) and temperature. Local winds of thermal origin include breezes. They are better expressed in cloudless anticyclone weather and are especially common on the western coasts of the tropics, where heated continents are washed by the waters of cold currents. Depending on their properties and origin (temperature or type of landscape over which they are formed), we grouped other local winds into three groups: cold, mountain-valley and desert. Separately, the local names of the Baikal winds were given.

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A source of information: Romashova T.V. Geography in figures and facts: Textbook / - Tomsk: 2008.