Trade winds - what are they? Monsoons Monsoons are steady winds.

Already from the middle of the 17th century. Mariners knew in general terms the patterns in the zonal structure of the prevailing winds in the World Ocean. Modern science provides an explanation for this pattern in the zonal structure of atmospheric pressure over the Earth's surface (§8).

Rice. 17. Trade winds

Sailors have long known winds that are stable in their constancy or change directions: trade winds, monsoons, breezes, etc.

Trade winds- these are the stable winds of the tropics, northeast in the northern and southeast in the southern hemispheres, blowing on the side of the subtropical center of action of the atmosphere facing the equator (Fig. 17). The speed of the trade winds is low - on average 5–8 m/s at the earth's surface. The conditions for the distribution of atmospheric pressure change little in the tropics, so the trade winds have great directional stability. However, during the season, the subtropical center of atmospheric action may undergo certain changes. Thus, usually one anticyclone is formed over each ocean of both hemispheres in the subtropics. On daily weather maps there may be more of them - often two, sometimes three over each ocean; over the South Pacific - up to four. As a result, the trade winds of both hemispheres can change the above directions. The migration of the centers of subtropical anticyclones can have a similar effect on the direction of trade winds. Therefore, trade winds in the same place can change the northeast direction to the east and southeast, then again to the northeast, etc.

Monsoons– seasonal winds, most pronounced and stable in tropical latitudes, arising due to ocean-land thermal heterogeneity. Monsoons, like all other air currents on Earth, are associated with cyclonic activity. The tropical monsoon regime consists of a seasonal change in the position of subtropical anticyclones and equatorial depression. The stability of monsoons is associated with a stable distribution of atmospheric pressure during each season, and their seasonal change is associated with fundamental changes in the distribution of pressure from season to season. The total baric gradients change direction sharply from season to season, and along with this the direction of the prevailing winds also changes.

If there is an ocean on both sides of the equator, then the seasonal shifts of the subtropical center of action of the atmosphere are small and the monsoons do not develop much, for example, over the Pacific Ocean.

Another thing with continents. Over Africa, for example, atmospheric pressure varies greatly from January to June. An area of ​​high pressure dominates over the central regions of Africa in summer, and the crest of the Azores anticyclone in winter; over southern Africa in winter there is also an anticyclone, and in summer there is a deep depression. In this regard, the direction of pressure gradients over the coast of tropical Africa changes sharply from season to season over a wide zone, which is the cause of monsoon winds here.

The monsoon circulation is especially pronounced in the Indian Ocean basin, where seasonal changes in hemispheric temperature are amplified by the huge continent of Eurasia north of the equator, warmed in summer and very cool in winter. The winter monsoon in the Indian Ocean basin is called northeast, and the summer monsoon is called southwest. In eastern China and Korea, the winter monsoon is northern or northwestern, and the summer monsoon is southern or southeastern. This depends on the structure of the pressure field and the direction of the isobars and, consequently, the direction of the pressure gradients (Fig. 18).

Breezes– reversible winds of the coasts of seas and oceans, with a semi-diurnal periodicity of direction changes. Breezes are especially pronounced over the coasts in the zone of subtropical anticyclones, where they are observed in all seasons of the year. In temperate and high latitudes, breezes are observed only in the warm season. For example, on the Black, Azov and Caspian Seas, breezes are observed from April to September.

Breeze circulation is explained by the restructuring of the pressure field day and night over land and sea. Thermal heterogeneity of sea and land leads to a change in the direction of baric gradients and, consequently, to a change in wind direction (Fig. 19).

The speed of the sea breeze is slightly higher than the speed of the coastal breeze and is 3–5 m/s (in the tropics up to 8 m/s). Breezes are especially pronounced in clear, windless weather, which is typical for the central regions of anticyclones. Breeze circulation covers a layer of the troposphere up to 1–2 km vertically and extends deep into the sea or land to tens of kilometers from the coastline. The sea breeze reduces the average air temperature by 2–3° and increases humidity by 10–20%.

Bora- a strong and gusty wind blowing from low mountains towards the warm sea. Bora belongs to the so-called katabatic winds associated with the flow of cold dense air masses along mountain slopes towards the sea.

Winds similar to the Novorossiysk and Novaya Zemlya Bors are known in many other seas of the World Ocean: the Baku Nord on the Caspian Sea, the Mistral on the Mediterranean coast of France, the North Sea in the Gulf of Mexico (Mexico, USA), etc.

The bora is caused by the passage of a cold front through the coastal ranges. Cold air abruptly passes over the low mountains (the wind is especially strong on the passes) and rushes down in a dense stream towards the nearby warm sea.

In straits, narrows, fiords when sailing along the coast, at capes, ends of islands, etc., there may be features of the wind regime associated with the coastal (angular) effect. These features are described in detail in the hydrometeorological sketches of the sailing directions.

When powerful cumulonimbus (thunderstorm) clouds form, which is possible in conditions of particularly strong instability of air masses, vertical vortices of small diameter can arise. Emerging vortices over the sea are called tornadoes, and over land - blood clots (in the USA - tornadoes). A tornado has the appearance of a dark cloud column several tens of meters in diameter (a tornado is up to 100–200 m), descending in the form of a funnel from the lower base of the cloud to the surface of the water or land. Wind speeds in a tornado reach 50–100 m/s and, with a strong vertical component, can cause catastrophic destruction. The proximity of atmospheric fronts can stimulate the process of tornado formation, especially in continental tropical air (in the USA in maritime tropical air from the Gulf of Mexico).

Scheme of the general circulation of the atmosphere.

The Earth's atmosphere is in constant motion. Air currents differ in both speed and direction. Close interaction with the underlying surface, the properties of which quickly change in time and space, leads to the fact that the instantaneous picture of atmospheric movement turns out to be unusually complex.

The construction of average daily, seasonal and long-term synoptic maps allows us to identify general (predominant) patterns of atmospheric movements. The system of macroscale air currents over the globe is called the general circulation of the atmosphere.

Identification of the main patterns of general atmospheric circulation is the scientific basis for both long-term and short-term weather forecasts.

It has now been established that the reason for the stable, persistent features of the general circulation of the atmosphere is zonality in the distribution of pressure (§ 8) and the associated cyclonic activity on the planet.

Zonal transfers manifesting themselves in the troposphere are characterized by predominant easterly winds in the tropical zone (trade winds), westerlies in temperate latitudes, and again easterly winds in subpolar and polar latitudes (Fig. 20).

Questions for self-control:

1. Causes of wind. What is a pressure gradient? Explain its components.

2. What forces influence the characteristics of the pressure gradient?

3. What are geostrophic and gradient winds?

4. What is the essence of the Beaufort scale?

5. What types of air flows do you know?

6. What are local winds?

7. What is the peculiarity of the wind distribution on the globe?

We invite you to go on an unusual journey. Let us follow the winds of the seasons today. “Mausim” - in Arabic - season, time of year, this is where the word “monsoon” comes from. Winds of the seasons that blow from opposite directions in winter and summer.

Let's first Let's look at the situation in the summer: There is a lot of sun and it heats the land to a greater extent. But why? Everything is not so complicated, firstly, water has the property that it is difficult to heat and difficult to cool. Water, of all substances, is the most difficult to heat, so it is said that its heat capacity is equal to unity. The volumetric heat capacity of air is equal to 0.000307, ​​i.e., to heat the air it is necessary to apply 3257 times less heat than is required for water. Conversely, it is 3257 times easier to cool air than water.

Plus, water, unlike land, is also transparent, which means the sun’s rays penetrate into the water column and warm it, and not just the surface layers.

So, we settled on the fact that in the summer the sun heats the land more than the ocean. Therefore, the air over land is heated and rises, leaving behind an area of ​​low pressure. Above the ocean, the air is colder and, therefore, located closer to the ground, and here an area of ​​​​high pressure arises. That's almost all!!! A holy place is never empty and cold air is directed from the ocean to land to fill the “empty” space. Or in other words, high pressure forces air into areas of lower pressure.

Why is the air humid in summer? Here, too, everything is simple, it came from the ocean, and there is a lot of water there :) In the summer, under the influence of the sun, it evaporates and saturates the air.

Now let's consider what happens in winter. There is little sun here and it does not play an important role. But again, everything happens thanks to the amazing properties of water discussed earlier. Over the long summer, the water has absorbed a lot of heat, and in winter it begins to slowly release it, while the air above the land cools down almost as soon as the sun goes away. Therefore, now, all the air over the ocean is heated due to the heat accumulated in the water, and the air over land without the sun cools down.

And again, where the air is warm, the pressure is low, and where it is cold, the pressure is high. And the wind blows from an area of ​​high pressure to an area of ​​low pressure. Those. in our case, in winter the monsoon winds blow from land to the ocean, and I think it’s clear why they are dry :-).

For a better understanding, also watch the video: “Why does the wind blow?”

Monsoon climate areas.

Summer monsoons come from the sea and bring with them rain and dampness; in winter, the wind blows from the land and gives dry and clear weather.

India is classic monsoon territory. This natural phenomenon has long been known to sailors, because the correct change of winds was very important for navigation.

What does spring mean to us? Awakening of nature, rebirth. The onset of the rainy summer monsoon carries the same significance on the Indian mainland. Many poets have sung this season in their works. In addition to India, the South Asian monsoon also covers Indochina, and then China.

And finally, the Australian monsoons cover the northern part of Australia and the Malay Archipelago. These are the areas of the monsoon country.

Modern Russian physical map of the world with sea currents. Among other things, you can find the monsoon current that goes around India.

And now, we invite you to get acquainted with wet and variable-humid monsoon forests.

Permanently wet forests. Huge humidity and always hot air temperatures. The flora and fauna are very rich. These forests are impenetrable jungles, with several layers of plants that never shed their leaves. The animals are usually small in size, since large individuals would have difficulty making their way through difficult areas. For humans, these forests also pose a challenge. Even today you can find places untouched and unexplored by us.

Variably wet forests. Precipitation does not occur all year round, but only during the rainy season. Plants have to shed their leaves to protect themselves from excess evaporation. Animals also have to adapt, so the diversity of flora and fauna here is inferior to the constantly humid forests.

Unfortunately, these forests are increasingly threatened by our civilization. And restoring their previous appearance takes a lot of time. Therefore, it is worth thinking again about how to preserve this wonderful splendor of nature.

And finally, I suggest watching a video film: BBC: Natural World. Monsoon / Natural World. Monsoon.

The general circulation of the atmosphere includes trade winds, moderate westerly winds, eastern (katabatic) winds of the polar regions, and monsoons.

Wind occurs due to differences in atmospheric pressure. Since there are relatively constant belts on Earth, the prevailing winds(also called constant, predominant, dominant or predominant).

Air masses moving with stable winds move in a certain order. They also create a complex system of air currents on a global scale. It is called the general circulation of the atmosphere (from the Latin word circulation- rotation).

Between the earth's atmospheric pressure belts, relatively stable prevailing winds, or winds of predominant directions, are formed.

Trade winds

Among the constant winds, the most famous are trade winds.

Trade winds - winds that are stable throughout the year, directed from tropical latitudes to equatorial latitudes and generally having an eastern direction.

Passes are formed in a hot thermal zone and blow from an area of ​​high pressure in the region of 30° N. w. and 30° S. w. towards the equator - areas with lower pressure (Fig. 31). If the Earth did not rotate, then the winds in the Northern Hemisphere would blow exactly from north to south. But due to the rotation of the Earth, the winds deviate from the direction of their movement: in the Northern Hemisphere - to the right, and in the Southern Hemisphere - to the left. This phenomenon is called the Coriolis effect, named after the French scientist, and it manifests itself not only in relation to winds, but also, for example, sea currents and the erosion of the corresponding banks of large rivers (in the Northern Hemisphere - right, in the Southern - left).

The trade wind of the Northern Hemisphere is a northeast wind, and the trade wind of the Southern Hemisphere is a southeast wind.

The trade winds blow at a fairly high speed, approximately 5-6 m/s, and weaken, converging near the equator - a calm zone is formed there. The trade winds over the Ocean are particularly constant. This was noted by sailors of the past who sailed on sailing ships and were very dependent on the winds. It is believed that the name "passat" comes from the Spanish vientedepasada, which means “wind favorable to moving.” Indeed, during the time of the sailing fleet, they helped to travel from Europe to America.

Western winds of temperate latitudes

From the high-pressure area of ​​the hot zone, winds blow not only towards the equator, but also in the opposite direction - towards the temperate latitudes, where the low-pressure belt is also located. These winds, like the trade winds, are deflected by the Earth's rotation (Coriolis effect). In the Northern Hemisphere they blow from the southwest, and in the Southern Hemisphere they blow from the northwest. Therefore these winds are called westerly winds of temperate latitudes or western transfer(Fig. 31).

We constantly encounter the western transfer of air masses in our latitudes in Eastern Europe. With westerly winds, sea air of temperate latitudes most often comes to us from the Atlantic. In the Southern Hemisphere, latitudes where westerly winds form over the gigantic continuous surface of the Ocean and reach enormous speeds are called “roaring co-fate winds.” Material from the site

Eastern (katabatic) winds of the polar regions

Eastern (katabatic) winds of the polar regions blow towards low pressure belts of moderate latitudes.

Monsoons

Stable winds are often classified as monsoons. Monsoons occur due to unequal heating of land and ocean in summer and winter. The land area is much larger in the Northern Hemisphere. Therefore, monsoons are well expressed here on the eastern coasts of Eurasia and North America, where in the middle latitudes there is a significant contrast in the warming of land and ocean. A special type is the tropical monsoons, which dominate South and Southeast Asia.

Unlike other prevailing winds, monsoons are seasonal winds. They change direction twice a year. The summer monsoon blows from the ocean to the land and brings moisture (rainy season), and the winter monsoon blows from the land to the ocean (dry season).

On this page there is material on the following topics:

• Prevailing winds at the equator

• What are monsoons? in what directions do they blow?

• What are constant winds called?

• They helped make the journey from Europe to America, they are called

• On the map, mark the trade winds and the west winds of the temperate latitudes.

Questions about this material:

SOUTH AMERICA I. In terms of its position relative to the equator, South America most closely resembles... 1) North America

3) Australia

2) Africa 4) Antarctica

II. South America is being washed...

1) Indian Ocean from the west, Atlantic - from the east

2) Atlantic - from the east, Pacific - from the west

3) Quiet - from the east, Atlantic - from the west

4) Atlantic - from the east, Indian - from the west

III. In the central part of South America intersects...

1) Northern Tropic

2) Equator

3) South Tropic

4) The Antarctic Circle

IV. In places where the South American platform rises,...

1) lowlands

2) plateaus

3) high mountains

4) medium-high mountains

V. The greatest contrast and variety of relief is observed in...

1) South America

3) Australia

4) Antarctica

VI. The most intense action of the Earth's internal forces manifests itself within...

1) Brazilian plateau

2) Guiana Plateau

3) Andes mountains

4) Amazonian lowland

VII. The lowest temperatures in July are characteristic of... the mainland

VIII. Moisture for most of the continent comes from... the ocean

2) Atlantic

3) Indian

4) Arctic

IX. Humid air is brought to most of the continent...

2) monsoons

3) trade winds

4) westerly winds of temperate latitudes

X. The formation of large river systems is facilitated by... continents

1) soils and vegetation

2) vegetation and climate

3) climate and terrain

4) relief and fauna

1. What number on the map indicates Cape Agulhas?

A) 1 B) 2 C)3 D)4
2. What are the coordinates of the easternmost point of Africa?
A) 16° S 3°E
B) 10° N 51°E
B) 51° N 11 east
D) 16° N 3° W
3. What type of climate is indicated by shading on the map?
A) Subequatorial
B) Tropical desert
B) Tropical humid
D) Equatorial
4. Which country is indicated on the map by a contour line?
A) Congo
B) Egypt
B) Somalia
D) Ethiopia
5. What conclusion can be drawn about the climate of Africa based on the fact that the continent is crossed by the equator and both tropics?
A) Africa receives large amounts of heat all year round
B) Africa is in the zone of trade winds
C) Africa has tropical and equatorial climate zones
D) All of the above conclusions
6. Which researcher made a great contribution to the study of Africa - discovered Victoria Falls, studied Lake Nyasa?
A) Vasco da Gama B) V.V. Junker B) D. Livingston D) N.I. Vavilov
7. What is located north of the East African Plateau?
A) Cape Mountains B) Drakensberg Mountains C) Mount Kilimanjaro D) Ethiopian Highlands
8. In southern and eastern Africa more than in northern:
A) Oil B) Phosphorites C) Uranium ores D) Gas
9. In the subequatorial zone of the Northern Hemisphere in Africa, precipitation falls:
A) Throughout the year B) in summer C) In winter D) In ​​September and March
10. In the tropical latitudes of southern Africa, more precipitation falls along the east coast than along the west, because there:
A) humid equatorial air masses act
B) cold currents cool the air and promote the formation of precipitation
B) Monsoons occur in the southern hemisphere in summer.
D) Trade winds bring moist air from the Indian Ocean
11. The deepest river in Africa, deep throughout the year, does not form a delta, it is:
A) Nile, B) Congo C) Zambezi D) Niger
12. Which lake is the deepest in Africa?
A) Victoria B) Nyasa C) Tanganyika D) Chad
13. What plant or animal is not typical for the savannah zone?
A) Hippopotamus B) Gorilla C) Acacia D) Baobab
14. What peoples live in northern Africa?
A) Arab peoples B) Bushmen C) Negroids D) Pygmies
15. Which country in Africa is the largest in terms of population?
A) Egypt
B) South Africa
B) Algeria
D) Nigeria

Option 1 Match: pressure indicators a) 749 mm Hg;

1) below normal;

b) 760 mmHg; 2) normal;

c) 860 mmHg; 3) above normal.

The difference between the highest and lowest air temperatures

called:

a) pressure; b) air movement; c) amplitude; d) condensation.

3. The reason for the uneven distribution of solar heat on the Earth’s surface

is:

a) distance from the sun; b) spherical;

c) different thickness of the atmospheric layer;

4. Atmospheric pressure depends on:

a) wind force; b) wind direction; c) air temperature differences;

d) relief features.

The sun is at its zenith at the equator:

The ozone layer is located in:

a) troposphere; b) stratosphere; c) mesosphere; d) exosphere; e) thermosphere.

Fill in the blank: the air shell of the earth is - _________________

8. Where is the least power of the troposphere observed:

a) at the poles; b) in temperate latitudes; c) at the equator.

Place the heating steps in the correct sequence:

a) heating the air; b) sun rays; c) heating of the earth's surface.

At what time in the summer, in clear weather, is the highest temperature observed?

air: a) at noon; b) before noon; c) afternoon.

10. Fill in the blank: when climbing mountains, atmospheric pressure..., for every

10.5 m at….mmHg.

Calculate the atmospheric pressure in Narodnaya. (Find the height of the vertices at

map, take the blood pressure at the foot of the mountains as 760 mm Hg)

The following data was recorded during the day:

max t=+2’C, min t=-8’C; Determine the amplitude and average daily temperature.

Option 2

1. At the foot of the mountain, blood pressure is 760 mm Hg. What will the pressure be at an altitude of 800 m:

a) 840 mm Hg. Art.; b) 760 mm Hg. Art.; c) 700 mm Hg. Art.; d) 680 mm Hg. Art.

2. Average monthly temperatures are calculated:

a) by the sum of average daily temperatures;

b) dividing the sum of average daily temperatures by the number of days in a month;

c) from the difference in the sum of temperatures of the previous and subsequent months.

3. Match:

pressure indicators

a) 760 mm Hg. Art.; 1) below normal;

b) 732 mm Hg. Art.; 2) normal;

c) 832 mm Hg. Art. 3) above normal.

4. The reason for the uneven distribution of sunlight over the earth's surface

is: a) distance from the Sun; b) the sphericity of the Earth;

c) a thick layer of the atmosphere.

5. Daily amplitude is:

a) the total number of temperature readings during the day;

b) the difference between the highest and lowest air temperatures in

during the day;

c) temperature variation during the day.

6. What instrument is used to measure atmospheric pressure:

a) hygrometer; b) barometer; c) rulers; d) thermometer.

7. The sun is at its zenith at the equator:

8. The layer of the atmosphere where all weather phenomena occur:

a) stratosphere; b) troposphere; c) ozone; d) mesosphere.

9. A layer of the atmosphere that does not transmit ultraviolet rays:

a) troposphere; b) ozone; c) stratosphere; d) mesosphere.

10. At what time in summer in clear weather is the lowest air temperature:

a) at midnight; b) before sunrise; c) after sunset.

11. Calculate the blood pressure of Mount Elbrus. (Find the height of the peaks on the map, the blood pressure at the bottom

Take the mountains conditionally for 760 mm Hg. Art.)

12. At an altitude of 3 km, the air temperature = - 15 ‘C, which is the air temperature at

Earth's surface:

a) + 5’C; b) +3’C; c) 0’C; d) -4’C.

Answer the question) Very necessary) 1. how people discovered and studied the earth 2. Continents. Parts of the world 3. Name and show the major ones on the map

landforms

4.What does the geography of continents and oceans study?

5. Hypotheses of the origin of continents and oceans

6. determine the geographical coordinates of the extreme points of Australia

7.history of the discovery of Antarctica

8.describe the major river systems of South America on a map

9.characterize the climate zone

10. Regularities of the geographical envelope

11. Systematic belts of the earth

12. determine the geographic coordinates of the extreme points of continent Africa

13history of discovery and exploration of Central Asia

14characterize the Arctic Ocean

15Determine the extent of Africa from north to south

16climate maps, features of the distribution of heat and moisture on the surface of the earth

17reserves of Africa

18Describe the Amazon River

19physical and geographical characteristics of the Pacific Ocean

20value of natural resources (mineral, climatic, water, land, biological)

21show seas inhabiting continent Eurasia

22main types of air masses and their influence on climate

23need for international cooperation in the use of nature

24description of the Nile River according to plan

25 constant winds and conditions for their formation

26characteristics of southern European countries

27describe the population of mainland Australia

28waters of the world's oceans

29features of nature in Great Britain

30determine the geographical coordinates of Italy

31natural areas of Africa

32future of the oceans

34determine the geographic coordinates of the extreme points of the Eurasian continent

35originality of the organic world of Australia

36current formations and their types

37description of Italy according to plan

38changes in the nature of the continent of South America under the influence of human activity

39characterize any natural area

40determine the length of the Australian mainland from west to east in kilometers

41maps - the second language of geography

42inland waters of Eurasia

43determine the geographic coordinates of the extreme points of the continent of South America

45nature of Antarctica

46relief features of Australia

47seas washing the continent of North America

48development of the earth by man

49continental and oceanic crust

50show on political map

51features of the nature of Antarctica

52change of nature under the influence of human economic activity

53characteristics of the Don River according to plan

54natural complexes of land and ocean

56modern exploration of the continent of Antarctica

57show large lithospheric plates on the map

58role of the atmosphere in the life of the earth

59features of geographical oceania

60characteristics of a learned traveler (optional)

61climatic zones of the earth

62location of mineral deposits on the South American mainland

63characteristics of the Atlantic Ocean

64geographical shell our common home

65relief of the oceans

66describe the geographical location of the continent of South America according to plan

The greatest amount of precipitation falls in a) equatorial latitudes b) polar latitudes c) temperate latitudes d) tropical latitudes........ Which of

Are the listed winds constant? Write the answer as a sequence of letters in alphabetical order. a) monsoons b) breezes c) westerly winds d) trade winds...

Air flow is a fairly variable phenomenon in the natural world. The wind may subside or blow with renewed vigor, or change its original direction. But there are winds that always have one direction and change it quite rarely. In this article we will look in detail at what trade winds and monsoons are, what their activity is and their occurrence.

Types of winds

Wind is an air flow that moves horizontally over the ground. This natural phenomenon occurs due to differences in atmospheric pressure. Air flows always arise in an area of ​​high pressure, and from there they are directed to an area of ​​lower pressure.

When the globe rotates, the direction of the winds changes. Therefore, in the north, air flows deviate to the right, and in the southern hemisphere to the left. Wind may also occur randomly when the weather changes.

Experts in the field of meteorology also identify constant winds that almost never change direction. The most important of these are breezes, monsoons and trade winds.

Trade winds

Trade winds are steady winds that result from differences in atmospheric pressure in the two hemispheres and at the equator. But, interestingly, they are formed only in the tropical region.

In addition, trade winds are winds deflected due to the rotation of the globe. In the northern hemisphere, their flows are directed to the southwest from the northeast, and in the south there is a reverse deviation - from southeast to northwest.

It is worth noting that the definition of the word “trade winds” is the same in all encyclopedias. These are winds that are stable in humidity and temperature, which are the main factor in shaping the climate in a particular area.

From the above it became clear what trade winds are. But what is their origin?

What does the word "trade winds" mean?

In any explanatory dictionary, frivolity is characterized as changeability and inconstancy. But the trade winds are something that breaks this statement.

The ancient sailors knew the fact of their positive effects. With winds such as the trade winds, this influence was expressed in the fact that, according to signs, a smooth blow meant a successful outcome of the entire sea voyage. After all, air currents pushed the ships in the right direction.

Spanish travelers gave such winds a special name, which sounded like “viento de pasade” - something that has a beneficial effect on movement. German and Dutch navigators also included the term "pasade".

In the Russian language, the word “trade winds” appeared thanks to Peter the Great. It is worth noting that such natural phenomena are not typical for our country; they are most often found in tropical zones. Being far from the equatorial zone, the trade winds weaken and can only spread in open space above the water surface. But even in this case, the strength of the trade winds does not exceed 3 or 4 points. Near land, the trade winds gradually develop or transform into monsoons.

Origin of trade winds

Climatic and weather conditions in a certain area have a special influence on the process of wind formation. In some parts of our planet, such an impact is the result of the formation of a specific local cyclone wind. Such air masses, along with constant ones, play an important role in the circulation process, and also form climatic conditions in certain zones and regions of the Earth.

On the globe, the sun's rays warm up the equator and the closest zones to it the most, so the air there always has a high temperature. For this reason, in areas close to the equator, the upward air flow is stable.

From the northern and southern zones, cold air masses rush to the place where the air rises. The inertial force of rotation helps the air masses to deviate slightly to the side, and not move only straight along a given path. Therefore, trade winds are winds that blow with a slight deviation to the side.

Cold air, rising, continues to cool even more, which leads to its gradual descent, but the air outflow directs it back and the Coriolis law comes into play here. Then the upper trade winds arise (this phenomenon is also called counter-trade winds).

Monsoons

What are monsoons? Both trade winds in geography and monsoons are winds that differ in several features. Monsoons occur as a result of pressure changes caused by temperature differences. The main feature of these winds is that they have the opposite direction at any time of the year. Monsoons blow either from water to land or vice versa.

In the winter, the air above the water is warmer than above the land, and the pressure is lower, so the flows are directed towards the sea. In summer the reverse process occurs. Precipitation occurs because winds blow from the sea to the land.

In the tropics, monsoon activity is quite high. An example is India, where mountains help stop wet winds. This is why Burma, Northern India and Nepal suffer from high rainfall. In addition, India almost always experiences humid summers.

Origin of the monsoons

Monsoons owe their appearance to the annual cycle of atmospheric pressure distribution. During the hot period, the earth warms up faster than the water, and the heat penetrates into the lower layer of the atmosphere. The heated air masses rush upward, and a low pressure zone appears above the ground.

The air pocket is filled with cold air, which is distributed above the water surface. Winds moving from water to land bring precipitation. Unlike monsoons, trade winds cannot do this.

Influence of wind activity

It is not the wind itself that is of interest to specialists, but the reasons that can cause it and the places where its pronounced activity is observed. Monsoons and trade winds are winds of tropical zones. Moreover, trade winds can blow all year from one hemisphere to another and vice versa, but monsoons are considered seasonal winds, which have different directions at different times of the year. This is often the case in the Indian Ocean.

The described winds have a great influence on the climate. For example, Indochina suffers from dry weather in the summer due to northeastern air currents. The lifestyle of the population of those countries depends only on the changing seasons, each of which brings its own natural phenomena. Based on climatic conditions, people determine when to start agricultural work and when it can be completed.

In addition, the influence of trade winds and monsoons was known to ancient sailors. These air masses helped them make historical journeys across the seas and oceans.