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Distribution of light and heat on Earth

Find a match: Climate Weather a) average annual precipitation b) average daily temperature c) wind direction and speed d) wind rose e) type of precipitation f) cloudiness g) average long-term temperature h) temperature of the warmest and coldest month

Why is there a change of seasons on Earth?

Solstice (summer solstice and winter solstice) Moments when the Sun's height above the horizon at noon is highest (summer solstice, June 22) or lowest (winter solstice, December 22). In some years, the solstice shifts to the 21st, as the length of the calendar year changes (365 or 366 days).

Summer solstice On the day of the summer solstice, the longest day in the Northern Hemisphere, the entire region beyond the Arctic Circle is illuminated, the Sun does not set. In the Southern Hemisphere at this time, the shortest day, the entire region beyond the Arctic Circle is in the shadow, the Sun does not rise.

Winter solstice On the winter solstice, the picture is reversed: the shortest day in the Northern Hemisphere, the longest in the Southern. On days close to the solstice, the length of the day and the midday height of the Sun change little, hence the term "solstice".

Equinox (vernal equinox and autumnal equinox) Moments when the sun's rays touch both poles, and the earth's axis is perpendicular to the rays. The vernal equinox occurs on March 21, the autumn equinox on September 23; in some years, the equinox is shifted to the 22nd. The northern and southern hemispheres are equally illuminated, at all latitudes the day is equal to night, at one pole the Sun rises, at the other it sets.

Tropics Tropics - Northern Tropic and Southern Tropic - parallels, respectively, with latitude north and south about 23.5 °. On the summer solstice (June 22), the Sun at noon stands at its zenith over the Tropic of the North, or the Tropic of Cancer; On the day of the winter solstice (December 22) - over the Southern Tropic, or Tropic of Capricorn. At any latitude between the tropics, the Sun is at its zenith twice a year; North of the Northern Tropic and south of the Southern Tropic, the sun is never at its zenith.

Polar circles The polar circles (the Arctic Circle and the Antarctic Circle) are parallels, respectively, with the north and south latitude of about 66.5 °. North of the Arctic Circle and south of the Antarctic Circle, there is a polar day (in summer) and a polar night (in winter). The area from the Arctic Circle to the Pole in both hemispheres is called the Arctic Circle.

Obelisk to the Arctic Circle Residents of Salekhard can be proud of the unique geographical position of their city. The fact is that Salekhard is located on the Arctic Circle and is divided by it into two parts. In the center of the city, on a symbolic dividing line, the world's only obelisk to the Arctic Circle is erected.

Polar day Polar day is a period when the Sun at high latitudes does not descend beyond the horizon around the clock. The duration of the polar day is the longer, the further to the pole from the Arctic circle. In the polar circles, the Sun does not set only on the solstice, at 68 ° latitude the polar day lasts about 40 days, at the North Pole 189 days, at the South Pole slightly less, due to the unequal speed of the Earth's orbit in the winter and summer semesters. Latitude Length of polar day Length of polar night 66.5 ° 1 1 70 ° 64 60 80 ° 133 126 90 ° 186 179 Length of polar day and polar night at different latitudes of the Northern Hemisphere (days).

Polar night Polar night is a period when the Sun at high latitudes does not rise above the horizon around the clock - a phenomenon opposite to the polar day is observed simultaneously with it at the corresponding latitudes of the other hemisphere. Latitude Length of polar day Length of polar night 66.5 ° 1 1 70 ° 64 60 80 ° 133 126 90 ° 186 179 Length of polar day and polar night at different latitudes of the Northern Hemisphere (days).

Illumination belts Illumination belts are parts of the Earth's surface bounded by the tropics and polar circles and differing in terms of illumination conditions. There is a tropical belt between the tropics; here twice a year (and in the tropics - once a year) you can observe the midday Sun at its zenith. From the Arctic Circle to the Pole, there are polar belts in each hemisphere; there is a polar day and a polar night. In the temperate zones, located in the Northern and Southern Hemispheres between the tropic and the polar circle, the sun does not exist at its zenith, the polar day and polar night are not observed.

Illumination belts Belt name Belt characteristics Boundaries between belts North polar There is a polar night and a polar day at 66.5 ° N. - Arctic Circle 23.5 ° N - Northern Tropic 23.5 ° S lat. - Southern Tropic 66.5 ° S lat. - Antarctic circle Northern temperate There is no polar day or polar night, the Sun never stands at its zenith Tropical Sun is at its zenith twice a year at any latitude and once at a latitude of the tropics Southern temperate Sun is never at its zenith, not there is neither a polar day nor a polar night South polar There is a polar night and a polar day

Fill in the table Date Northern Hemisphere Southern Hemisphere June 22 Day… nights At a parallel of 23.5 ° N. -… At parallel 66.5 ° N -… Day… nights At parallel 23.5 ° S. -… At parallel 66.5 ° S -… September 23 1. Day… night 2. At the equator… 1. Day… night 2. At the equator… December 22 Day… night At parallel 23.5 ° N ... -… At parallel 66.5 ° N -… Day… nights At parallel 23.5 ° S. - ... At the parallel 66.5 ° S - ... March 21 1. Day ... night 2. At the equator ... 1. Day ... night 2. At the equator ...

Checking the Date Northern Hemisphere Southern Hemisphere June 22 Summer solstice Day longer than night Parallel 23.5 ° N The sun is at its zenith At the parallel 66.5 ° N-polar day Day of winter solstice Day is shorter than night At parallel 66.5 ° S. –Polar night September 23 Day is equal to night At the equator - the sun is at its zenith Day is equal to night At the equator - the sun is at its zenith December 22 The day is shorter than night At 66.5 ° N. - polar night The day is longer than the night At 23.5 ° S lat. Sun at zenith At 66.5 ° S latitude - polar day March 21 Day is equal to night At the equator The sun is at its zenith Day is equal to night At the equator The sun is at its zenith

Introduction

climate equatorial tropical latitude

Travelers and navigators of antiquity drew attention to the difference in the climates of those or other countries that they happened to visit. The first attempt to establish the Earth's climate system belongs to Greek scientists. It is said that the historian Polybius (204 - 121 BC) was the first to divide the entire earth into 6 climatic zones - two hot (uninhabited), two temperate and two cold. At that time it was already clear that the degree of cold or warmth on the earth depends on the angle of inclination of the incident sunlight. Hence the very word "climate" (klima - slope) arose, which for many centuries meant a certain belt of the earth's surface, bounded by two latitudinal circles.

In our time, the relevance of studying the climate has not faded away. To date, the distribution of heat and its factors have been studied in detail, many classifications of climates have been given, including the Alisov classification, which is most used in the territory of the former USSR, and Köppen, which is widespread in the world. But the climate changes over time, so at the moment the study of the climate is also relevant. Climatologists are studying climate change and the causes of these changes in detail.

The purpose of the course work: to study the distribution of heat on Earth as the main climate-forming factor.

Coursework objectives:

1) Study the factors of heat distribution over the Earth's surface;

2) Consider the main climatic zones of the Earth.

Heat distribution factors

The sun as a source of heat

The Sun is the closest star to Earth and is a huge ball of incandescent plasma at the center of the solar system.

Any body in nature has its own temperature, and, therefore, its own intensity of energy radiation. The higher the radiation intensity, the higher the temperature. With extremely high temperatures, the Sun is a very strong source of radiation. Inside the sun, processes take place in which helium atoms are synthesized from hydrogen atoms. These processes are called nuclear fusion processes. They are accompanied by the release of a huge amount of energy. This energy causes the Sun to heat up to 15 million degrees Celsius at its core. On the surface of the Sun (photosphere), the temperature reaches 5500 ° C (11) (3, p. 40-42).

Thus, the Sun emits a huge amount of energy that brings heat to the Earth, but the Earth is located at such a distance from the Sun that only a small part of this radiation reaches the surface, which allows living organisms to live comfortably on our planet.

Earth rotation and latitude

The shape of the globe and its movement in a certain way affect the flow of solar energy to the earth's surface. Only part of the sun's rays falls vertically on the surface of the globe. When the Earth rotates, the rays fall vertically only in a narrow belt located at an equal distance from the poles. Such a belt on the globe is the equatorial belt. With distance from the equator, the surface of the Earth becomes more and more inclined in relation to the rays of the Sun. At the equator, where the sun's rays fall almost vertically, the greatest heating is observed. The hottest belt of the Earth is located here. At the poles, where the sun's rays fall very obliquely, there is eternal snow and ice. In middle latitudes, the amount of heat decreases with distance from the equator, that is, as the height of the Sun above the horizon decreases with approaching the poles (Fig. 1, 2).

Rice. 1. The distribution of sunlight on the surface of the Earth on the days of the equinox

Rice. 2.

Rice. 3. The rotation of the earth around the sun

If the earth's axis were perpendicular to the plane of the earth's orbit, then the inclination of the sun's rays would be constant for each latitude, and the conditions of illumination and heating of the earth would not change during the year. In reality, the earth's axis makes an angle of 66 ° 33 "with the plane of the earth's orbit. This leads to the fact that, while maintaining the axis orientation in world space, each point of the earth's surface meets the sun's rays at angles that change during the year (Fig. 1-3). On March 21 and September 23, the sun's rays fall vertically above the equator at noon.Due to the diurnal rotation and perpendicular position in relation to the plane of the Earth's orbit, at all latitudes day is equal to night. These are the days of the spring and autumn equinoxes (Fig. 1). June 22 are solar rays at noon fall vertically over the parallel of 23 ° 27 "N. sh., which is called the northern tropic. Above the surface north of 66 ° 33 "N. The sun does not set over the horizon and there is a polar day. This parallel is called the Arctic Circle, and the date June 22 - the day of the summer solstice. The surface south of 66 ° 33" S. NS. is not illuminated by the Sun at all and the polar night reigns there. This parallel is called the South Arctic Circle. On December 22, the sun's rays fall at noon vertically over the parallel of 23 ° 27 "S, which is called the southern tropic, and the date of December 22 is the day of the winter solstice. At this time, the polar night sets north of the Arctic Circle, and south of southern polar circle - polar day (Fig. 2) (12).

Since the tropics and polar circles are the boundaries of the change in the illumination regime and the heating of the earth's surface during the year, they are taken for the astronomical boundaries of the heat zones on Earth. Between the tropics there is a hot zone, from the tropics to the polar circles - two temperate zones, from the polar circles to the poles - two cold zones. This pattern of distribution of illumination and heat is actually complicated by the influence of various geographic patterns, which will be considered below (12).

Changes in the heating conditions of the earth's surface during the year are the reason for the change in seasons (winter, summer, and transitional seasons) and determine the annual rhythm of processes in the geographic envelope (annual variation of soil and air temperature, life processes, etc.) (12).

The daily rotation of the Earth around its axis causes significant temperature fluctuations. In the morning, with the rising of the sun, the arrival of solar radiation begins to exceed the own radiation of the earth's surface, so the temperature of the earth's surface increases. The greatest heating will be observed when the Sun is at its highest position. As the sun approaches the horizon, its rays become more inclined to the earth's surface and heat it up less. After the sun sets, the flow of heat stops. Night cooling of the earth's surface continues until a new sunrise (8).

Video tutorial 2: Atmosphere structure, meaning, study

Lecture: Atmosphere. Composition, structure, circulation. Distribution of heat and moisture on the Earth. Weather and climate

Atmosphere

Atmosphere can be called an all-pervading shell. Its gaseous state allows it to fill microscopic holes in the soil, water is dissolved in water, animals, plants and humans cannot exist without air.

The conditional thickness of the envelope is 1500 km. Its upper boundaries dissolve in space and are not clearly marked. The atmospheric pressure at sea level at 0 ° C is 760 mm. rt. Art. The gas shell consists of 78% nitrogen, 21% oxygen, 1% other gases (ozone, helium, water vapor, carbon dioxide). The density of the air envelope changes with rise in height: the higher, the more rarefied the air. This is why climbers can experience oxygen deprivation. The very surface of the earth has the greatest density.

Composition, structure, circulation

Layers are distinguished in the shell:

Troposphere, 8-20 km thick. Moreover, at the poles, the thickness of the troposphere is less than at the equator. This small layer contains about 80% of the entire mass of air. The troposphere tends to heat up from the surface of the earth, therefore its temperature is higher near the earth itself. With a rise up 1 km. the temperature of the air envelope decreases by 6 ° C. In the troposphere, there is an active movement of air masses in the vertical and horizontal directions. It is this shell that is the "factory" of the weather. Cyclones and anticyclones are formed in it, westerly and easterly winds blow. All water vapor is concentrated in it, which condenses and sheds rain or snow. This layer of the atmosphere contains impurities: smoke, ash, dust, soot, everything we breathe. The layer bordering the stratosphere is called the tropopause. This is where the temperature drop ends.

Approximate boundaries stratosphere 11-55 km. Up to 25 km. There are minor changes in temperature, and above it begins to rise from -56 ° C to 0 ° C at an altitude of 40 km. Another 15 kilometers, the temperature does not change, this layer was called the stratopause. The stratosphere contains ozone (O3), a protective barrier for the Earth. Due to the presence of the ozone layer, harmful ultraviolet rays do not penetrate the earth's surface. Recently, anthropogenic activity has led to the destruction of this layer and the formation of "ozone holes". Scientists claim that the cause of the "holes" is the increased concentration of free radicals and freon. Under the influence of solar radiation, gas molecules are destroyed, this process is accompanied by glow (northern lights).

From 50-55 km. the next layer begins - mesosphere, which rises to 80-90 km. In this layer, the temperature decreases, at an altitude of 80 km it is -90 ° С. In the troposphere, the temperature rises again to several hundred degrees. Thermosphere stretches up to 800 km. Upper bounds exosphere are not determined, since the gas is scattered and partially escapes into outer space.

Heat and moisture

The distribution of solar heat on the planet depends on the latitude of the place. The equator and the tropics receive more solar energy, since the angle of incidence of the sun's rays is about 90 °. The closer to the poles, the angle of incidence of the rays decreases, respectively, the amount of heat also decreases. The sun's rays passing through the air shell do not heat it up. Only when it hits the ground, the sun's heat is absorbed by the surface of the earth, and then the air is heated from the underlying surface. The same happens in the ocean, except that water heats up more slowly than land and cools more slowly. Therefore, the proximity of seas and oceans affects the formation of the climate. In summer, the sea air brings us coolness and precipitation, in winter it warms, since the surface of the ocean has not yet spent its heat accumulated over the summer, and the earth's surface has cooled down quickly. Marine air masses form above the surface of the water, therefore, they are saturated with water vapor. Moving over land, air masses lose moisture, bringing precipitation. Continental air masses, formed above the earth's surface, are usually dry. The presence of continental air masses brings hot weather in summer and clear frosty in winter.

Weather and climate

Weather- the state of the troposphere in a given place for a certain period of time.

Climate- long-term weather regime, typical for a given area.

The weather can change during the day. Climate is a more constant characteristic. Each physical-geographical region is characterized by a certain type of climate. The climate is formed as a result of the interaction and mutual influence of several factors: the latitude of the place, the prevailing air masses, the relief of the underlying surface, the presence of underwater currents, the presence or absence of water bodies.

There are belts of low and high atmospheric pressure on the earth's surface. Equatorial and temperate belts of low pressure, at the poles and in the tropics, the pressure is high. Air masses move from high pressure to low pressure. But since our Earth rotates, these directions deviate, in the northern hemisphere to the right, in the southern hemisphere to the left. Trade winds blow from the tropical zone to the equator, westerly winds blow from the tropical zone to the temperate zone, and polar east winds blow from the poles to the temperate zone. But in each belt, land areas alternate with water areas. Depending on whether the air mass has formed over land or over the ocean, it can bring heavy rains or a clear sunny surface. The amount of moisture in the air masses is influenced by the relief of the underlying surface. Moisture-saturated air masses pass over flat areas without obstacles. But if there are mountains on the way, heavy humid air cannot move through the mountains, and is forced to lose some, or even all of the moisture on the slope of the mountains. The east coast of Africa has a mountainous surface (Drakensberg Mountains). The air masses that form over the Indian Ocean are saturated with moisture, but all the water is lost on the coast, a hot dry wind comes inland. This is why most of southern Africa is deserted.

Video tutorial 2: Atmosphere structure, meaning, study

Lecture: Atmosphere. Composition, structure, circulation. Distribution of heat and moisture on the Earth. Weather and climate

Atmosphere

Atmosphere can be called an all-pervading shell. Its gaseous state allows it to fill microscopic holes in the soil, water is dissolved in water, animals, plants and humans cannot exist without air.

The conditional thickness of the envelope is 1500 km. Its upper boundaries dissolve in space and are not clearly marked. The atmospheric pressure at sea level at 0 ° C is 760 mm. rt. Art. The gas shell consists of 78% nitrogen, 21% oxygen, 1% other gases (ozone, helium, water vapor, carbon dioxide). The density of the air envelope changes with rise in height: the higher, the more rarefied the air. This is why climbers can experience oxygen deprivation. The very surface of the earth has the greatest density.

Composition, structure, circulation

Layers are distinguished in the shell:

Troposphere, 8-20 km thick. Moreover, at the poles, the thickness of the troposphere is less than at the equator. This small layer contains about 80% of the entire mass of air. The troposphere tends to heat up from the surface of the earth, therefore its temperature is higher near the earth itself. With a rise up 1 km. the temperature of the air envelope decreases by 6 ° C. In the troposphere, there is an active movement of air masses in the vertical and horizontal directions. It is this shell that is the "factory" of the weather. Cyclones and anticyclones are formed in it, westerly and easterly winds blow. All water vapor is concentrated in it, which condenses and sheds rain or snow. This layer of the atmosphere contains impurities: smoke, ash, dust, soot, everything we breathe. The layer bordering the stratosphere is called the tropopause. This is where the temperature drop ends.

Approximate boundaries stratosphere 11-55 km. Up to 25 km. There are minor changes in temperature, and above it begins to rise from -56 ° C to 0 ° C at an altitude of 40 km. Another 15 kilometers, the temperature does not change, this layer was called the stratopause. The stratosphere contains ozone (O3), a protective barrier for the Earth. Due to the presence of the ozone layer, harmful ultraviolet rays do not penetrate the earth's surface. Recently, anthropogenic activity has led to the destruction of this layer and the formation of "ozone holes". Scientists claim that the cause of the "holes" is the increased concentration of free radicals and freon. Under the influence of solar radiation, gas molecules are destroyed, this process is accompanied by glow (northern lights).

From 50-55 km. the next layer begins - mesosphere, which rises to 80-90 km. In this layer, the temperature decreases, at an altitude of 80 km it is -90 ° С. In the troposphere, the temperature rises again to several hundred degrees. Thermosphere stretches up to 800 km. Upper bounds exosphere are not determined, since the gas is scattered and partially escapes into outer space.

Heat and moisture

The distribution of solar heat on the planet depends on the latitude of the place. The equator and the tropics receive more solar energy, since the angle of incidence of the sun's rays is about 90 °. The closer to the poles, the angle of incidence of the rays decreases, respectively, the amount of heat also decreases. The sun's rays passing through the air shell do not heat it up. Only when it hits the ground, the sun's heat is absorbed by the surface of the earth, and then the air is heated from the underlying surface. The same happens in the ocean, except that water heats up more slowly than land and cools more slowly. Therefore, the proximity of seas and oceans affects the formation of the climate. In summer, the sea air brings us coolness and precipitation, in winter it warms, since the surface of the ocean has not yet spent its heat accumulated over the summer, and the earth's surface has cooled down quickly. Marine air masses form above the surface of the water, therefore, they are saturated with water vapor. Moving over land, air masses lose moisture, bringing precipitation. Continental air masses, formed above the earth's surface, are usually dry. The presence of continental air masses brings hot weather in summer and clear frosty in winter.

Weather and climate

Weather- the state of the troposphere in a given place for a certain period of time.

Climate- long-term weather regime, typical for a given area.

The weather can change during the day. Climate is a more constant characteristic. Each physical-geographical region is characterized by a certain type of climate. The climate is formed as a result of the interaction and mutual influence of several factors: the latitude of the place, the prevailing air masses, the relief of the underlying surface, the presence of underwater currents, the presence or absence of water bodies.

There are belts of low and high atmospheric pressure on the earth's surface. Equatorial and temperate belts of low pressure, at the poles and in the tropics, the pressure is high. Air masses move from high pressure to low pressure. But since our Earth rotates, these directions deviate, in the northern hemisphere to the right, in the southern hemisphere to the left. Trade winds blow from the tropical zone to the equator, westerly winds blow from the tropical zone to the temperate zone, and polar east winds blow from the poles to the temperate zone. But in each belt, land areas alternate with water areas. Depending on whether the air mass has formed over land or over the ocean, it can bring heavy rains or a clear sunny surface. The amount of moisture in the air masses is influenced by the relief of the underlying surface. Moisture-saturated air masses pass over flat areas without obstacles. But if there are mountains on the way, heavy humid air cannot move through the mountains, and is forced to lose some, or even all of the moisture on the slope of the mountains. The east coast of Africa has a mountainous surface (Drakensberg Mountains). The air masses that form over the Indian Ocean are saturated with moisture, but all the water is lost on the coast, a hot dry wind comes inland. This is why most of southern Africa is deserted.

Atmosphere- the air shell surrounding the globe, associated with it by gravity and taking part in its daily and annual rotation.

Atmospheric air consists of a mechanical mixture of gases, water vapor and impurities. The composition of the air up to an altitude of 100 km is 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.03% carbon dioxide, and only 0.01% is accounted for by all other gases: hydrogen, helium, water vapor, ozone. The gases that make up the air are constantly being mixed. The percentage of gases is fairly constant. However, the carbon dioxide content changes. Burning oil, gas, coal, and a decrease in the number of forests leads to an increase in the content of carbon dioxide in the atmosphere. This contributes to an increase in the air temperature on Earth, since carbon dioxide passes solar energy to the Earth, and the thermal radiation of the Earth delays. Thus, carbon dioxide is a kind of "insulation" for the Earth.

There is little ozone in the atmosphere. At an altitude of 25 - 35 km, a concentration of this gas is observed, the so-called ozone screen (ozone layer). The ozone screen performs the most important function of protection - it detains the ultraviolet radiation of the Sun, which is destructive for all life on Earth.

Atmospheric water is in the air in the form of water vapor or suspended condensation products (drops, ice crystals).

Atmospheric impurities(aerosols) - liquid and solid particles found mainly in the lower atmosphere: dust, volcanic ash, soot, ice crystals and sea salt, etc. The amount of atmospheric impurities in the air increases during strong forest fires, dust storms, volcanic eruptions ... The underlying surface also affects the amount and quality of atmospheric impurities in the air. So, over the deserts there is a lot of dust, over the cities there are many small solid particles, soot.

The presence of impurities in the air is associated with the content of water vapor in it, since dust, ice crystals and other particles serve as nuclei around which water vapor condenses. Like carbon dioxide, water vapor in the atmosphere serves as a "heat insulator" for the Earth: it inhibits radiation from the earth's surface.

The mass of the atmosphere is one millionth of the mass of the earth.

The structure of the atmosphere. The atmosphere has a layered structure. Layers of the atmosphere are distinguished on the basis of changes in air temperature with height and other physical properties (table 1).

Table 1.The structure of the atmosphere

Sphere of atmosphere	Height of the lower and upper bounds	Temperature change with altitude
Troposphere		Downgrade
Stratosphere	8-18 - 40-50 km	Enhancement
Mesosphere	40-50 km - 80 km	Downgrade
Thermosphere		Enhancement
Exosphere	Above 800 km (conventionally, it is believed that the atmosphere extends to an altitude of 3000 km)

Troposphere— the lower shell of the atmosphere, containing 80% air and almost all water vapor. The thickness of the troposphere is not the same. At tropical latitudes - 16-18 km, in temperate latitudes - 10-12 km, and in polar latitudes - 8-10 km. Everywhere in the troposphere, the air temperature drops by 0.6 ° С for every 100 m ascent (or 6 ° C for 1 km). The troposphere is characterized by vertical (convection) and horizontal (wind) air movements. All types of air masses are formed in the troposphere, cyclones and anticyclones appear, clouds, precipitation, and fog are formed. Weather forms mainly in the troposphere. Therefore, the study of the troposphere is of particular importance. The lower layer of the troposphere, which is called surface layer, it is highly dusty and contains volatile microorganisms.

The transitional layer from the troposphere to the stratosphere is called tropopause. The rarefaction of air in it sharply increases, its temperature drops to -60 ° From above the poles to -80 ° From over the tropics. The lower air temperature over the tropics is due to powerful ascending air currents and a higher position of the troposphere.

Stratosphere- the layer of the atmosphere between the troposphere and the mesosphere. The gas composition of the air is similar to the troposphere, but contains much less water vapor and more ozone. The highest concentration of this gas (ozone screen) is observed at an altitude of 25 to 35 km. Up to an altitude of 25 km, the temperature changes little with altitude, and above it begins to rise. Temperatures vary with latitude and season. Nacreous clouds are observed in the stratosphere; it is characterized by high wind speeds and jet streams of air.

The upper atmosphere is characterized by auroras and magnetic storms. Exosphere- the outer sphere from which light atmospheric gases (for example, hydrogen, helium) can flow into outer space. The atmosphere does not have a sharp upper boundary and gradually passes into outer space.

The presence of the atmosphere is of great importance to the Earth. It prevents excessive heating of the earth's surface during the day and cooling at night; protects the Earth from the sun's ultraviolet radiation. A significant part of the meteorites burns up in the dense layers of the atmosphere.

Interacting with all the shells of the Earth, the atmosphere participates in the redistribution of moisture and heat on the planet. It is a condition for the existence of organic life.

Solar radiation and air temperature. The air is heated and cooled from the earth's surface, which in turn is heated by the sun. The entire totality of solar radiation is called solar radiation... The main part of solar radiation is scattered in the world space, only one two-billionth part of solar radiation comes to the Earth. Radiation is direct and diffuse. Solar radiation that reaches the surface of the Earth in the form of direct sunlight emanating from the solar disk on a clear day is called direct radiation... Solar radiation that has undergone scattering in the atmosphere and arrives at the surface of the Earth from the entire firmament is called scattered radiation... Scattered solar radiation plays a significant role in the energy balance of the Earth, being the only source of energy in the surface layers of the atmosphere in cloudy weather, especially at high latitudes. The combination of direct and scattered radiation entering a horizontal surface is called total radiation.

The amount of radiation depends on the duration of the illumination of the surface by the sun's rays and the angle of their incidence. The smaller the angle of incidence of the sun's rays, the less solar radiation the surface receives and, therefore, the less the air above it heats up.

Thus, the amount of solar radiation decreases when moving from the equator to the poles, since the angle of incidence of the sun's rays and the duration of illumination of the territory in winter time decrease.

The amount of solar radiation is also affected by cloudiness and transparency of the atmosphere.

The greatest total radiation exists in tropical deserts. At the poles on the day of the solstices (at the North - on June 22, at the South - on December 22), with a non-setting Sun, the total solar radiation is greater than at the equator. But due to the fact that the white surface of snow and ice reflects up to 90% of the sun's rays, the amount of heat is negligible, and the surface of the earth does not heat up.

The total solar radiation reaching the Earth's surface is partially reflected by it. Radiation reflected from the surface of the earth, water or clouds on which it falls is called reflected. But still, most of the radiation is absorbed by the earth's surface and turns into heat.

Since the air heats up from the surface of the earth, its temperature depends not only on the factors listed above, but also on the height above sea level: the higher the terrain is, the lower the temperature (decreases by 6 ° C with every kilometer in the troposphere).

Affects the temperature and distribution of land and water, which are heated unevenly. Land heats up quickly and cools quickly, water heats up slowly, but retains heat longer. Thus, the air over land is warmer during the day than over water, and colder at night. This influence affects not only the diurnal, but also the seasonal characteristics of the change in air temperature. Thus, in coastal areas, under the same conditions, the summer is cooler and the winter is warmer.

Due to the heating and cooling of the Earth's surface day and night, during the warm and cold seasons, the air temperature changes throughout the day and year. The highest temperatures of the surface layer are observed in the desert regions of the Earth - in Libya near the city of Tripoli +58 ° С, in Death Valley (USA), in Termez (Turkmenistan) - up to +55 ° С. The lowest are in the interior regions of Antarctica - up to -89 ° С. In 1983, at Vostok station in Antarctica, -83.6 ° С is the minimum air temperature on the planet.

Air temperature- a widely used and well-studied characteristic of the weather. The air temperature is measured 3-8 times a day, determining the average daily; according to the daily average, the monthly average is determined, according to the monthly average - the annual average. The maps depict the temperature distribution isotherms. Typically July, January and annual temperatures are used.

Atmosphere pressure. Air, like any body, has a mass: 1 liter of air at sea level has a mass of about 1.3 g. For every square centimeter of the earth's surface, the atmosphere presses with a force of 1 kg. This is the average air pressure above sea level at latitude 45 ° at a temperature of 0 ° C corresponds to the weight of a mercury column with a height of 760 mm and a section of 1 cm 2 (or 1013 mb.). This pressure is taken as normal pressure. Atmosphere pressure - the force with which the atmosphere presses on all objects in it and on the earth's surface. The pressure is determined at each point of the atmosphere by the mass of the overlying column of air with a base equal to one. With increasing altitude, atmospheric pressure decreases, since the higher the point is, the lower the height of the air column above it. As it rises upward, the air is rarefied and its pressure decreases. In high mountains, the pressure is much less than at sea level. This regularity is used when determining the absolute height of the terrain by the magnitude of pressure.

Baric stage- the vertical distance at which atmospheric pressure decreases by 1 mm Hg. Art. In the lower layers of the troposphere, up to a height of 1 km, the pressure decreases by 1 mm Hg. Art. for every 10 m of height. The higher, the slower the pressure decreases.

In the horizontal direction near the earth's surface, the pressure changes unevenly, depending on time.

Baric gradient- an indicator characterizing the change in atmospheric pressure above the earth's surface per unit distance and horizontally.

The magnitude of pressure, in addition to the height of the terrain above sea level, depends on the air temperature. The pressure of warm air is less than that of cold air, because due to heating it expands, and when it cools, it contracts. With a change in air temperature, its pressure changes. Since the change in air temperature on the globe is zonal, zoning is also characteristic of the distribution of atmospheric pressure on the earth's surface. A low pressure belt stretches along the equator, at 30-40 ° latitudes to the north and south - high pressure belts, at 60-70 ° latitudes the pressure is lowered again, and in polar latitudes - areas of high pressure. The distribution of belts of high and low pressure is associated with the peculiarities of heating and air movement at the Earth's surface. In equatorial latitudes, the air heats up well throughout the year, rises and spreads towards tropical latitudes. Approaching 30-40 ° latitudes, the air cools down and descends, creating a belt of increased pressure. In polar latitudes, cold air creates areas of increased pressure. Cold air constantly descends, and in its place comes air from temperate latitudes. The outflow of air to polar latitudes is the reason that a low pressure belt is created in temperate latitudes.

Pressure belts exist all the time. They are only slightly shifted to the north or south, depending on the season ("following the Sun"). The exception is the low pressure belt of the Northern Hemisphere. It only exists in the summer. Moreover, over Asia, a huge area of ​​low pressure is formed with its center in tropical latitudes - the Asian minimum. Its formation is explained by the fact that over a huge land mass, the air warms up strongly. In winter, the land, which occupies significant areas in these latitudes, is greatly cooled, the pressure above it increases, and areas of increased pressure are formed over the continents - the Asian (Siberian) and North American (Canadian) winter maximums of atmospheric pressure. Thus, in winter, the belt of low pressure in the temperate latitudes of the Northern Hemisphere "breaks". It persists only over the oceans in the form of closed areas of low pressure - the Aleutian and Icelandic minima.

The influence of the distribution of land and water on the patterns of change in atmospheric pressure is also expressed in the fact that throughout the year, baric maxima exist only over the oceans: Azores (North Atlantic), North Pacific, South Atlantic, South Pacific, South Indian.

The atmospheric pressure is constantly changing. The main reason for a change in pressure is a change in air temperature.

Atmospheric pressure is measured using barometers... The aneroid barometer consists of a hermetically sealed thin-walled box, inside of which the air is rarefied. When the pressure changes, the walls of the box are pressed in or protruded. These changes are transmitted to the arrow, which moves on a scale, graduated in millibars or millimeters.

The maps show the pressure distribution over the Earth. isobars... Most often, the maps indicate the distribution of isobars in January and July.

The distribution of areas and belts of atmospheric pressure significantly affects air currents, weather and climate.

Wind- horizontal air movement relative to the earth's surface. It occurs as a result of an uneven distribution of atmospheric pressure and its movement is directed from areas of higher pressure to areas where the pressure is lower. Due to the continuous change in pressure in time and space, the speed and direction of the wind are constantly changing. The direction of the wind is determined by the part of the horizon from which it blows (the north wind blows from north to south). Wind speed is measured in meters per second. With height, the direction and strength of the wind change due to a decrease in the friction force, as well as in connection with a change in pressure gradients.

So, the reason for the wind is the difference in pressure between different territories, and the reason for the difference in pressure is the difference in heating. The deflection force of the Earth's rotation acts on the winds.

Winds are diverse in origin, character, meaning. The main winds are breezes, monsoons, trade winds.

Breeze— local wind (sea coasts, large lakes, reservoirs and rivers), which changes its direction twice a day: during the day it blows from the side of the reservoir to the land, and at night - from land to the reservoir. Breezes arise from the fact that during the day the land heats up more than the water, which is why the warmer and lighter air above the land rises and colder air flows from the side of the reservoir to its place. At night, the air above the reservoir is warmer (because it cools more slowly), so it rises up, and in its place the air masses move from the land - heavier, cooler ones (Fig. 12). Other types of local winds are hair dryer, bora, etc.

Rice. 12

Trade winds- constant winds in the tropical regions of the Northern and Southern Hemispheres, blowing from high pressure belts (25-35 ° N and S) to the equator (into the low pressure belt). Under the influence of the Earth's rotation around its axis, the trade winds deviate from their original direction. In the Northern Hemisphere, they blow from northeast to southwest, in the Southern Hemisphere - from southeast to northwest. The trade winds are characterized by high stability of direction and speed of movement. Trade winds have a great impact on the climate of the territories under their influence. This is especially evident in the distribution of precipitation.

Monsoons— winds that, depending on the seasons of the year, change direction to the opposite or close to it. In the cold season, they blow from the mainland to the ocean, and in the warm season - from the ocean to the mainland.

Monsoons are formed due to the difference in air pressure arising from the uneven heating of land and sea. In winter, the air is colder over land and warmer over the ocean. Consequently, the pressure is higher over the mainland, lower - over the ocean. Therefore, in winter, air moves from the mainland (areas of higher pressure) to the ocean (above which the pressure is lower). In the warm season, the opposite is true: monsoons blow from the ocean to the mainland. Therefore, in the areas of distribution of monsoons, precipitation falls, as a rule, in summer. Due to the rotation of the Earth around its axis, the monsoons deviate in the Northern Hemisphere to the right, and in the Southern Hemisphere - to the left of their original direction.

Monsoons are an important part of the general circulation of the atmosphere. Distinguish extratropical and tropical(equatorial) monsoons. In Russia, extratropical monsoons operate on the territory of the Far East coast. Tropical monsoons are more pronounced, they are most typical for South and Southeast Asia, where in some years several thousand millimeters of precipitation falls during the wet season. Their formation is explained by the fact that the equatorial low-pressure belt is slightly displaced to the north or south, depending on the season ("following the Sun"). In July, it is located at 15 - 20 ° N. NS. Therefore, the southeastern trade wind of the Southern Hemisphere, rushing to this low pressure belt, crosses the equator. Under the influence of the deflecting force of the Earth's rotation (around its axis) in the Northern Hemisphere, it changes its direction and becomes southwestern. This is the summer equatorial monsoon, which carries sea air masses of equatorial air up to latitude 20-28 °. Meeting the mountains of the Himalayas on its way, humid air leaves a significant amount of precipitation on their southern slopes. At Cherrapunja station in North India, the average annual precipitation exceeds 10,000 mm per year, and in some years even more.

From the high-pressure belts, the winds also blow towards the poles, but, deviating to the east, they change their direction to the west. Therefore, in temperate latitudes prevail westerly winds, although they are not as constant as the trade winds.

The prevailing winds in the polar regions are northeastern winds in the Northern Hemisphere and southeasterly in the South.

Cyclones and anticyclones. Due to the uneven heating of the earth's surface and the deflecting force of the Earth's rotation, huge (up to several thousand kilometers in diameter) atmospheric eddies - cyclones and anticyclones are formed (Fig. 13).

Rice. 13. Diagram of air movement

Cyclone - an ascending vortex in the atmosphere with a closed area of ​​reduced pressure, in which the winds blow from the periphery to the center (counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere). The average speed of the cyclone is 35 - 50 km / h, and sometimes up to 100 km / h. In a cyclone, air rises upward, which affects the weather. With the appearance of a cyclone, the weather changes quite sharply: winds intensify, water vapor rapidly condenses, generating powerful clouds, precipitation falls.

Anticyclone- a descending atmospheric vortex with a closed area of ​​increased pressure, in which winds blow from the center to the periphery (in the Northern Hemisphere - clockwise, in the Southern Hemisphere - counterclockwise). In the anticyclone, the air descends, becoming drier when warmed up, since the vapors contained in it move away from saturation. This, as a rule, excludes the formation of clouds in the central part of the anticyclone. Therefore, during the anticyclone, the weather is clear, sunny, without precipitation. Frosty in winter, hot in summer.

Water vapor in the atmosphere. There is always a certain amount of moisture in the atmosphere in the form of water vapor evaporated from the surface of oceans, lakes, rivers, soil, etc. Evaporation depends on air temperature, wind (even a weak wind increases evaporation three times, since all the time carries away the air saturated with water vapor and brings new portions of dry), the nature of the relief, vegetation cover, the color of the soil.

Distinguish volatility - the amount of water that could evaporate under given conditions per unit of time, and evaporation - the amount of water actually evaporated.

In the desert, evaporation is high and evaporation is negligible.

Air saturation... At any given temperature, the air can accept water vapor up to a certain limit (up to saturation).

The higher the temperature, the more maximum amount of water the air can contain. If you cool unsaturated air, it will gradually approach the saturation point. The temperature at which a given unsaturated air goes to saturation is called dew point. If the saturated air is cooled further, then excess water vapor will begin to thicken in it. Moisture will begin to condense, clouds will form, then precipitation will fall.

Therefore, to characterize the weather, it is necessary to know relative humidity - the percentage ratio of the amount of water vapor contained in the air to the amount that it may contain at saturation. Absolute humidity- the amount of water vapor in grams , currently in 1 m 3 of air.

Precipitation and its formation.Precipitation- water in liquid or solid state, falling from the clouds. The clouds are called accumulations of water vapor condensation products suspended in the atmosphere - water droplets or ice crystals. Depending on the combination of temperature and degree of moisture, droplets or crystals of various shapes and sizes are formed. Small droplets float in the air, larger ones begin to fall in the form of drizzle (drizzle) or light rain. Snowflakes form at low temperatures.

The scheme of precipitation formation is as follows: the air cools (more often when it rises upwards), approaches saturation, water vapor condenses, precipitation is formed.

Measurement of the amount of precipitation is carried out using a rain gauge - a cylindrical metal bucket 40 cm high and a cross-sectional area of ​​500 cm 2. All measurements of the amount of atmospheric precipitation are added up for each month, and the average monthly, and then the annual amount of precipitation is displayed.

The amount of precipitation in the territory depends on:

• air temperature (affects the evaporation and moisture holding capacity of the air);
• sea ​​currents (above the surface of warm currents, the air heats up and is saturated with moisture; when it is transferred to neighboring, colder regions, precipitation is easily released from it. surface, it expands, its saturation with moisture decreases, and precipitation is not formed in it);
• atmospheric circulation (where air moves from sea to land, precipitation is higher);
• the heights of the place and the direction of the mountain ranges (the mountains force the moisture-saturated air masses to rise, where, due to cooling, condensation of water vapor and the formation of precipitation occur; there is more precipitation on the windward slopes of the mountains).

Precipitation is uneven. It obeys the law of zoning, that is, it changes from the equator to the poles. In tropical and temperate latitudes, the amount of precipitation changes significantly when moving from the coast to the interior of the continents, which depends on many factors (atmospheric circulation, the presence of ocean currents, relief, etc.).

The fallout of atmospheric precipitation over most of the globe occurs unevenly throughout the year. Near the equator, the amount of precipitation changes insignificantly during the year; in subequatorial latitudes, there is a dry season (up to 8 months) associated with the action of tropical air masses, and a rainy season (up to 4 months) associated with the arrival of equatorial air masses. Moving from the equator to the tropics, the duration of the dry season increases and the rain season decreases. In subtropical latitudes, winter precipitation prevails (they are brought by moderate air masses). In temperate latitudes, precipitation falls throughout the year, but in the inner parts of the continents, more precipitation falls in the warm season. Summer precipitation also prevails in polar latitudes.

Weather- the physical state of the lower atmosphere in a certain area at a given moment or for a certain period of time.

Weather characteristics - air temperature and humidity, atmospheric pressure, cloudiness and precipitation, wind. Weather is an extremely variable element of natural conditions, subject to daily and annual rhythms. The daily rhythm is due to the heating of the earth's surface by the sun's rays during the day and nighttime cooling. The annual rhythm is determined by the change in the angle of incidence of sunlight throughout the year.

Weather is of great importance in human economic activity. Weather studies are carried out at meteorological stations using a variety of instruments. According to the information received at the meteorological stations, synoptic maps are drawn up. Synoptic map- a weather map on which the atmospheric fronts and weather data at a certain moment (air pressure, temperature, wind direction and speed, cloudiness, position of warm and cold fronts, cyclones and anticyclones, precipitation pattern) are plotted with conventional signs. Synoptic maps are compiled several times a day, their comparison allows one to determine the paths of movement of cyclones, anticyclones, atmospheric fronts.

Atmospheric front- zone of division of air masses of different properties in the troposphere. It occurs when the masses of cold and warm air approach and meet. Its width reaches several tens of kilometers at a height of hundreds of meters and a length of sometimes thousands of kilometers with a slight slope towards the Earth's surface. The atmospheric front, passing through a certain territory, dramatically changes the weather. Warm and cold fronts are distinguished among atmospheric fronts (Fig. 14)

Rice. fourteen

Warm front is formed with the active movement of warm air towards cold air. Then warm air flows onto the receding wedge of cold air and rises along the plane of separation. It cools down when it rises. This leads to condensation of water vapor, cirrus and stratus clouds and precipitation. With the arrival of a warm front, atmospheric pressure decreases; as a rule, warming and heavy, drizzling precipitation are associated with it.

Cold front formed when cold air moves towards warm air. Cold air, being heavier, flows under the warm air and pushes it up. In this case, stratocumulus rain clouds arise, from which precipitation falls in the form of showers with squalls and thunderstorms. Cooling, increased wind and increased air transparency are associated with the passage of the cold front. Weather forecasts are of great importance. Weather forecasts are made for different times. Usually the weather is predicted for 24 - 48 hours. Making long-term weather forecasts is associated with great difficulties.

Climate- a long-term weather regime typical for a given area. The climate influences the formation of soil, vegetation, fauna; determines the regime of rivers, lakes, swamps, influences the life of the seas and oceans, the formation of relief.

The distribution of climate on Earth is zonal. There are several climatic zones on the globe.

Climatic zones- latitudinal bands of the earth's surface, which have a homogeneous air temperature regime, due to the "norms" of the arrival of solar radiation and the formation of the same type of air masses with features of their seasonal circulation (table 2). Air masses- large volumes of air in the troposphere with more or less the same properties (temperature, humidity, dustiness, etc.). The properties of air masses are determined by the territory or water area over which they are formed.

Characteristics of zonal air masses:

equatorial - warm and humid;

tropical - warm, dry;

moderate - less warm, more humid than tropical, seasonal differences are characteristic;

arctic and antarctic - cold and dry.

Table 2.Climatic zones and air masses acting in them

Climatic zone	Active zonal air masses
	Summer	In winter
Equatorial	Equatorial
Subequatorial	Equatorial	Tropical
Tropical	Tropical
Subtropical	Tropical	Moderate
Moderate	Moderate latitudes (polar)
Subarctic Subantarctic	Moderate	Arctic Antarctic
Arctic antarctic	Arctic Subantarctic

Within the main (zonal) types of VM, there are subtypes - continental (forming over the mainland) and oceanic (forming over the ocean). The general direction of movement is characteristic of the air mass, but inside this volume of air there can be different winds. The properties of air masses change. Thus, maritime temperate air masses, carried by westerly winds to the territory of Eurasia, gradually warm up (or cool) when moving to the east, lose moisture and turn into continental temperate air.

Climatic factors:

• the geographical latitude of the place, since the angle of inclination of the sun's rays depends on it, which means the amount of heat;
• atmospheric circulation - prevailing winds bring certain air masses;
• ocean currents (see about atmospheric precipitation);
• the absolute height of the place (the temperature decreases with the height);
• remoteness from the ocean - on the coasts, as a rule, there are less sudden temperature changes (day and night, seasons); more rainfall;
• relief (mountain ranges can trap air masses: if a moist air mass meets mountains on its way, it rises, cools, moisture condenses and precipitation falls).

Climatic zones change from the equator to the poles, because the angle of incidence of the sun's rays changes. This, in turn, determines the law of zoning, i.e., the change in the components of nature from the equator to the poles. Within the climatic zones, climatic regions are distinguished - a part of the climatic zone that has a certain type of climate. Climatic regions arise due to the influence of various climate-forming factors (features of atmospheric circulation, the influence of ocean currents, etc.). For example, in the temperate climatic zone of the Northern Hemisphere, areas of continental, temperate continental, maritime and monsoon climates are distinguished.

General circulation of the atmosphere- a system of air currents on the globe, which facilitates the transfer of heat and moisture from one region to another. Air moves from high pressure areas to low pressure areas. Areas of high and low pressure are formed as a result of uneven heating of the earth's surface. Under the influence of the Earth's rotation, air currents deviate to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere. In equatorial latitudes, due to high temperatures, there is a constant low pressure belt with weak winds. The heated air rises and spreads at a height to the north and south. At high temperatures and ascending air movement, with high humidity, large clouds are formed. There is a lot of precipitation here.

Approximately between 25 and 30 ° N. and y. NS. the air sinks to the surface of the Earth, where, as a result, high pressure belts are formed. Near the Earth, this air is directed towards the equator (where there is low pressure), deviating in the Northern Hemisphere to the right, in the Southern Hemisphere - to the left. This is how trade winds are formed. There is a calm zone in the central part of the high-pressure belts: the winds are weak. Due to the descending currents of air, the air is dried and warmed up. Hot and dry areas of the Earth are located in these zones.

In temperate latitudes with centers around 60 ° N. and y. NS. the pressure is low. The air rises and then rushes to the polar regions. In temperate latitudes, western air transport prevails (the deflecting force of the Earth's rotation acts).

The polar latitudes are characterized by low air temperatures and high pressures. Coming from temperate latitudes, the air descends to the Earth and is again directed to temperate latitudes with northeastern (in the Northern Hemisphere) and southeasterly (in the Southern Hemisphere) winds. There is little precipitation (Fig. 15).

Rice. 15. Diagram of the general circulation of the atmosphere