How long does it take for the Earth to complete one revolution around the Sun? Why do the seasons change?

1. Dependence of the amount of light and heat entering the Earth on the height of the Sun above the horizon and the duration of the fall. Remember from the section “Earth - Planet” solar system"How the Earth rotates around the Sun during the year. You know that due to the inclination of the earth's axis relative to the orbital plane, the angle of incidence of the sun's rays on the earth's surface changes throughout the year.

The results of observations carried out using a gnomon in a schoolyard show that the higher the Sun is above the horizon, the greater the angle of incidence of the sun's rays and the length of time they fall. In this regard, the quantity also changes solar heat. If the sun's rays fall obliquely, the Earth's surface heats up less. This is clearly visible due to the low amount of solar heat in the morning and evening. If the sun's rays fall vertically, the Earth heats up more. This can be seen by the amount of heat at midday.

Now let's get acquainted with various phenomena associated with the rotation of the Earth around the Sun.

2. Summer solstice. In the Northern Hemisphere, the longest day is June 22 (Fig. 65.1). After this, the day stops lengthening and gradually shortens. That's why June 22 is called the summer solstice. On this day, the place where the sun's rays fall directly overhead corresponds to parallel 23.5° northern latitude. In the northern polar region from latitude 66.5° to the pole, the Sun does not set during the day, and a polar day sets in. In the southern hemisphere, on the contrary, from latitude 66.5° to the pole the Sun does not rise, polar night sets in. The duration of the polar day and polar night ranges from one day at the Arctic Circle to half a year towards the poles.

Rice. 65. The location of the globe on the days of the summer and winter solstice.

3. Autumn equinox. With the further rotation of the Earth in orbit, the northern hemisphere gradually turns away from the Sun, the day shortens, and the solstice zone decreases during the day. In the southern hemisphere, on the contrary, the days lengthen.

The area where the Sun does not set is shrinking. On September 23, the midday Sun at the equator is directly overhead, in the northern and southern hemispheres solar heat and light are distributed equally, day and night are equal throughout the planet. This is called the autumn equinox. Now at the North Pole the polar day ends and the polar night begins. Then, until mid-winter, the polar night region in the northern hemisphere gradually expands to 66.5° north latitude.

4. Winter solstice. September 23 at South Pole The polar night ends, the polar day begins. This will last until December 22nd. On this day, the lengthening of the day for the southern hemisphere and the shortening of the day for the northern hemisphere stops. This - winter solstice(Fig. 65.2).

On December 22, the Earth comes into a state opposite to June 22. Ray of the Sun along parallel 23.5° S. falls vertically, south of 66.5° S. In the polar region, on the contrary, the Sun does not set.

The parallel of 66.5° northern and southern latitudes, limiting the spread of the polar day and polar night on the pole side, is called the Arctic Circle.

5. The vernal equinox. Further in the northern hemisphere, the day lengthens, in the southern hemisphere it shortens. On March 21, day and night become equal again throughout the planet. At noon at the equator, the sun's rays fall vertically. The polar day begins at the North Pole, and the polar night begins at the South Pole.

6. Heat zones. We have noticed that the region where the midday Sun is at its zenith in the northern and southern hemispheres extends to a latitude of 23.5°. The parallels of this latitude are called the Tropic of the North and the Tropic of the South.
The polar day and polar night begin from the Northern and Southern Polar Circles. They pass along 66°33"N and 66()33"S. These lines separate belts that differ in their illumination by sunlight and the amount of incoming heat (Fig. 66).

Rice. 66. Thermal zones of the globe

On globe There are five thermal zones: one hot, two moderate and two cold.
Space earth's surface between the Northern and Southern tropics is classified as a hot zone. During the year, this belt receives the most sunlight, which is why there is a lot of heat. The days are hot all year round, it never gets cold and there is no snow.
From the Tropic of the Arctic to the Arctic Circle is the northern temperate zone, from the Tropic of the South to the Antarctic Circle is the southern temperate zone.
Temperate zones are in an intermediate position between the hot and cold zones in terms of day length and heat distribution. They clearly express the four seasons. In summer the days are long and the sun's rays fall directly, so the summer is hot. In winter, the Sun is not very high above the horizon, and the sun's rays fall obliquely; in addition, the length of the day is short, so it can be cold and frosty.
In each hemisphere, from the Arctic Circle to the poles, there are northern and southern cold zones. There are no several months in winter (at the poles up to 6 months) sunlight. Even in summer, the Sun is low on the horizon and the day length is short, so the Earth's surface does not have time to warm up. Therefore, winter is very cold; even in summer, snow and ice on the surface of the Earth do not have time to melt.

1. Using a tellurium (an astronomical instrument for demonstrating the movement of the Earth and planets around the Sun and the daily rotation of the Earth around its axis) or a globe with a lamp, observe how the sun's rays are distributed during the winter and summer solstices, the spring and autumn equinoxes?

2. Determine from the globe in which thermal zone is Kazakhstan located?

3. In your notebook, draw a diagram of thermal zones. Mark the poles, polar circles, Northern and Southern tropics, equator and label their latitudes.

4*. If the Earth's axis in relation to the orbital plane made an angle of 60°, then at what latitudes would the boundaries of the polar circles and tropics pass?

Introduction

climate equatorial tropical geographical latitude

Travelers and sailors of antiquity paid attention to the differences in climates of various countries that they visited. Greek scientists made the first attempt to establish the Earth's climate system. They say that the historian Polybius (204 - 121 BC) was the first to divide the entire earth into 6 climatic zones- two hot (uninhabited), two moderate and two cold. At that time, it was already clear that the degree of cold or heat on earth depended on the angle of inclination of the incident solar rays. This is where the word “climate” itself arose (klima - slope), which for many centuries denoted a certain zone of the earth’s surface, limited by two latitudinal circles.

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

Target course work: 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 Earth.

Heat distribution factors

The sun as a heat source

The Sun is the closest star to Earth, which is a huge ball of hot plasma in the center of the solar system.

Any body in nature has its own temperature, and, consequently, its own intensity of energy radiation. The higher the radiation intensity, the higher the temperature. Having extremely high temperatures, the Sun is a very strong source of radiation. Processes take place inside the Sun 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 temperatures of 15 million degrees Celsius at its core. On the surface of the Sun (photosphere) the temperature reaches 5500°C (11) (3, pp. 40-42).

Thus, the Sun emits a huge amount of energy, which 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 exist comfortably on our planet.

Earth rotation and latitude

The shape of the globe and its movement in a certain way influence the flow of solar energy to the earth's surface. Only a portion of the sun's rays fall vertically onto the surface of the globe. As 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 equatorial belt. As we move away from the equator, the Earth's surface 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. Here is located hot belt Earth. At the poles, where the rays of the Sun fall very obliquely, there are eternal snow and ice. In mid-latitudes, the amount of heat decreases with distance from the equator, that is, as the height of the Sun above the horizon decreases as it approaches the poles (Fig. 1,2).

Rice. 1. Distribution of solar rays on the Earth's surface during the equinoxes

Rice. 2.

Rice. 3. Rotation of the Earth around the Sun

If the Earth's axis were perpendicular to the plane of the Earth's orbit, then the tilt of the sun's rays would be constant at each latitude, and the Earth's lighting and heating conditions would not change throughout the year. In fact, 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 orientation of the axis in world space, each point on the earth's surface meets the sun's rays at angles that change throughout 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 daily rotation and perpendicular location relative to the plane of the Earth's orbit, day is equal to night at all latitudes. These are the days of the spring and autumn equinoxes (Fig. 1). June 22 is solar At noon the rays fall vertically above the parallel 23°27" N. sh., which is called the northern tropic. Above the surface north of 66°33"N latitude. The sun does not set below the horizon and polar day reigns there. This parallel is called the Arctic Circle, and the date June 22 is the summer solstice. The surface south of 66°33"S. w. It is not illuminated by the Sun at all and polar night reigns there. This parallel is called the Antarctic Circle. On December 22, the sun's rays fall vertically at noon above the parallel of 23°27" S, which is called the southern tropic, and the date December 22 is the winter solstice. At this time, polar night sets in 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 changes in the regime of illumination and heating of the earth's surface throughout the year, they are taken as the astronomical boundaries of thermal 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 there are two cold belts. This pattern of distribution of illumination and heat is actually complicated by the influence of various geographical patterns, which will be discussed below (12).

Changes in the heating conditions of the earth's surface during the year are the cause of the change of seasons (winter, summer and transition seasons) and determine the annual rhythm of processes in geographical envelope (annual course soil and air temperatures, life processes, etc.) (12).

The daily rotation of the Earth around its axis causes significant temperature fluctuations. In the morning, at sunrise, the arrival 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 occur when the Sun is at its highest position. As the Sun approaches the horizon, its rays become more inclined towards the earth's surface and heat it less. After sunset, the heat flow stops. Night cooling of the earth's surface continues until the new sunrise (8).

Atmosphere pressure - the pressure of atmospheric air on the objects in it and the earth's surface. Normal atmospheric pressure is 760 mmHg. Art. (101325 Pa). For every kilometer increase in altitude, the pressure drops by 100 mm.

Atmospheric composition:

The Earth's atmosphere is the air envelope of the Earth, consisting mainly of gases and various impurities (dust, water droplets, ice crystals, sea ​​salts, combustion products), the quantity of which is not constant. The main gases are nitrogen (78%), oxygen (21%) and argon (0.93%). The concentration of gases that make up the atmosphere is almost constant, with the exception of carbon dioxide CO2 (0.03%).

The atmosphere also contains SO2, CH4, NH3, CO, hydrocarbons, HC1, HF, Hg vapor, I2, as well as NO and many other gases in small quantities. Constantly located in the troposphere a large number of suspended solid and liquid particles (aerosol).

Climate and weather

Weather and climate are interrelated, but it is worth identifying the difference between them.

Weather- this is the state of the atmosphere over a certain area in certain moment time. In the same city, the weather can change every few hours: fog appears in the morning, a thunderstorm begins by lunchtime, and by the evening the sky clears of clouds.

Climate- a long-term, repeating weather pattern characteristic of a particular area. Climate affects the terrain, water bodies, flora and fauna.

Basic weather elements - precipitation(rain, snow, fog), wind, air temperature and humidity, cloudiness.

Precipitation- This is water in liquid or solid form that falls on the surface of the earth.

They are measured using an instrument called a rain gauge. This is a metal cylinder with a cross-sectional area of ​​500 cm2. Precipitation is measured in millimeters - this is the depth of the layer of water that appeared in the rain gauge after precipitation fell.

Air temperature determined using a thermometer - a device consisting of temperature scale and a cylinder partially filled with a specific substance (usually alcohol or mercury). The action of a thermometer is based on the expansion of a substance when heated and compression when cooled. One of the types of thermometer is the well-known thermometer, in which the cylinder is filled with mercury. The thermometer that measures the air temperature should be in the shade so that the sun's rays do not heat it up.

Temperature measurements are carried out at meteorological stations several times a day, after which the average daily, average monthly or average annual temperature is displayed.

Average daily temperature is the arithmetic average of temperatures measured at regular intervals during the day. Average monthly temperature is the arithmetic average of all average daily temperatures during the month, and the annual average is the arithmetic average of all average daily temperatures during the year. In one area, the average temperatures of each month and year remain approximately constant, since any large temperature fluctuations are leveled out by averaging. Currently, there is a tendency for average temperatures to gradually increase, a phenomenon called global warming. Promotion average temperature by a few tenths of a degree is imperceptible to humans, but has a significant impact on the climate, since along with the temperature the pressure and humidity of the air also change, and the winds also change.

Air humidity shows how saturated it is with water vapor. Absolute and relative humidity are measured. Absolute humidity is the amount of water vapor present in 1 cubic meter of air, measured in grams. When talking about the weather, they often use relative air humidity, which shows the percentage of the amount of water vapor in the air to the amount that is in the air at saturation. Saturation is a certain limit to which water vapor is in the air without condensing. Relative humidity cannot be more than 100%.

The saturation limit varies in different areas of the globe. Therefore, to compare humidity in different areas, it is better to use absolute indicator humidity, and to characterize the weather in a certain area - a relative indicator.

Cloudiness usually assessed using following expressions: cloudy - the whole sky is covered with clouds, partly cloudy - there are a large number of individual clouds, clear - the number of clouds is insignificant or absent.

Atmosphere pressure- a very important characteristic of the weather. Atmospheric air has its own weight, and for every point of the earth’s surface, for every object and Living being, located on it, presses the column of air. Atmospheric pressure is usually measured in millimeters of mercury. To make this measurement clear, let us explain what it means. On every square centimeter of surface air presses with the same force as a column of mercury 760 mm high. Thus, the air pressure is compared with the pressure of the mercury column. A number less than 760 means low blood pressure.

Temperature fluctuations

In any area the temperature is not constant. At night, due to lack of solar energy, the temperature drops. In this regard, it is customary to distinguish between average day and night temperatures. Also, the temperature fluctuates throughout the year. In winter, the average daily temperature is lower, gradually increases in the spring and gradually decreases in the fall, in summer the average daily temperature is the highest.

Distribution of light, heat and moisture across the Earth's surface

Solar heat and light are distributed unevenly over the surface of the spherical Earth. This is explained by the fact that the angle of incidence of the rays is different at different latitudes.

The earth's axis is inclined to the orbital plane at an angle. Its northern end is directed towards the North Star. The sun always illuminates half of the Earth. At the same time, either the Northern Hemisphere is more illuminated (and the day there lasts longer than in the other hemisphere), or, conversely, the Southern Hemisphere. Twice a year, both hemispheres are illuminated equally (then the length of the day in both hemispheres is the same).

The sun is the main source of heat and light on Earth. This one is huge gas ball with a surface temperature of about 6000 ° C, it emits a large amount of energy, which is called solar radiation. It heats our Earth, moves the air, forms the water cycle, and creates conditions for the life of plants and animals.

Passing through the atmosphere, part of solar radiation is absorbed, while part is scattered and reflected. Therefore, the flow of solar radiation, coming to the surface of the Earth, gradually weakens.

Solar radiation reaches the Earth's surface directly and diffusely. Direct radiation is a stream of parallel rays coming directly from the disk of the Sun. Scattered radiation comes from all over the sky. It is believed that the heat received from the Sun per 1 hectare of Earth is equivalent to the combustion of almost 143 thousand tons of coal.

The sun's rays passing through the atmosphere heat it up little. The atmosphere is heated by the Earth's surface, which absorbs solar energy and converts it into heat. Air particles coming into contact with a heated surface receive heat and carry it into the atmosphere. This heats up the lower layers of the atmosphere. Obviously, the more solar radiation the Earth's surface receives, the more it heats up, and the more the air heats up from it.

Numerous observations of air temperature showed that the highest temperature was observed in Tripoli (Africa) (+58°C), the lowest at Vostok station in Antarctica (-87.4°C).

The influx of solar heat and the distribution of air temperature depend on the latitude of the place. The tropical region receives more heat from the Sun than temperate and polar latitudes. The equatorial regions receive the most heat. The Sun is the star of the solar system, which is a source of enormous amounts of heat and dazzling light for planet Earth. Despite the fact that the Sun is located at a considerable distance from us and only a small part of its radiation reaches us, this is quite enough for the development of life on Earth. Our planet revolves around the Sun in an orbit. If with spaceship If you observe the Earth throughout the year, you will notice that the Sun always illuminates only one half of the Earth, therefore, there will be day there, and on the opposite half at this time there will be night. The earth's surface receives heat only during the day.

Our Earth is heating unevenly. The uneven heating of the Earth is explained by its spherical shape, therefore the angle of incidence of the sun's ray in different areas is different, which means that different parts of the Earth receive different quantity heat. At the equator, the sun's rays fall vertically, and they greatly heat the Earth. The further from the equator, the smaller the angle of incidence of the beam becomes, and therefore the less heat these areas receive. A beam of solar radiation of the same power heats a much smaller area at the equator, since it falls vertically. In addition, rays falling at a smaller angle than at the equator, penetrating the atmosphere, travel a longer path through it, as a result of which some of the sun's rays are scattered in the troposphere and do not reach the earth's surface. All this indicates that with distance from the equator to the north or south, the air temperature decreases, as the angle of incidence of the sun's ray decreases.

The distribution of precipitation around the globe depends on how many clouds containing moisture form over a given area or how many of them the wind can bring. Air temperature is very important, because intensive evaporation of moisture occurs precisely at high temperature. The moisture evaporates, rises and clouds form at a certain altitude.

Air temperature decreases from the equator to the poles, therefore, the amount of precipitation is maximum at equatorial latitudes and decreases towards the poles. However, on land, the distribution of precipitation depends on a number of additional factors.

There is a lot of precipitation over coastal areas, and as you move away from the oceans, their amount decreases. There is more precipitation on the windward slopes of mountain ranges and significantly less on the leeward ones. For example, on Atlantic coast In Norway, Bergen receives 1,730 mm of precipitation per year, while Oslo receives only 560 mm. Low mountains also affect the distribution of precipitation - on the western slope of the Urals, in Ufa, an average of 600 mm of precipitation falls, and on the eastern slope, in Chelyabinsk, 370 mm.

The greatest amount of precipitation falls in the Amazon basin, off the coast of the Gulf of Guinea and in Indonesia. In some areas of Indonesia, their maximum values ​​reach 7000 mm per year. In India, in the foothills of the Himalayas at an altitude of about 1300 m above sea level, there is the rainiest place on Earth - Cherrapunji (25.3 ° N and 91.8 ° E, where an average of more than 11,000 mm of precipitation falls per day). year Such an abundance of moisture brings to these places the humid summer southwest monsoon, which rises along the steep slopes of the mountains, cools and pours down with heavy rain.

The oceans, whose water temperature changes much more slowly than the temperature of the earth's surface or air, have a strong moderating effect on the climate. At night and in winter, the air over the oceans cools much more slowly than over land, and if the oceanic air masses moving over continents, this leads to warming. Conversely, during the day and summer the sea breeze cools the land.

The distribution of moisture on the earth's surface is determined by the water cycle in nature. Every second, huge amounts of water evaporate into the atmosphere, mainly from the surface of the oceans. Moist oceanic air, sweeping over the continents, cools. The moisture then condenses and returns to the earth's surface in the form of rain or snow. Partially it is stored in snow cover, rivers and lakes, and partially returns to the ocean, where evaporation occurs again. This completes the hydrological cycle.

The distribution of precipitation is also influenced by the currents of the World Ocean. Over the areas near which they pass warm currents, the amount of precipitation increases, as from warm weather water masses the air heats up, it rises and clouds with sufficient water content form. Over areas near which cold currents pass, the air cools and sinks, clouds do not form, and much less precipitation falls.

Since water plays a significant role in erosion processes, it thereby affects movements earth's crust. And any redistribution of masses caused by such movements under the conditions of the Earth rotating around its axis can, in turn, contribute to a change in the position of the Earth’s axis. During ice ages Sea levels are falling as water accumulates in glaciers. This, in turn, leads to the expansion of continents and increased climatic contrasts. Reduced river flows and lower sea levels prevent warm ocean currents from reaching cold regions, leading to further climate change.

Which is a source of enormous amounts of heat and dazzling light. Despite the fact that the Sun is located at a considerable distance from us and only a small part of its radiation reaches us, this is quite enough for the development of life on Earth. Our planet revolves around the Sun in an orbit. If you observe the Earth from a spaceship throughout the year, you will notice that the Sun always illuminates only one half of the Earth, therefore, there will be day there, and on the opposite half at this time there will be night. The earth's surface receives heat only during the day.

Our Earth is heating unevenly. The uneven heating of the Earth is explained by its spherical shape, so the angle of incidence of the sun's ray in different areas is different, which means that different parts of the Earth receive different amounts of heat. At the equator, the sun's rays fall vertically, and they greatly heat the Earth. The further from the equator, the smaller the angle of incidence of the beam becomes, and therefore the less heat these territories receive. A beam of solar radiation of the same power heats a much smaller area, since it falls vertically. In addition, rays falling at a smaller angle than at the equator, penetrating, travel a longer path in it, as a result of which some of the sun's rays are scattered in the troposphere and do not reach the earth's surface. All this indicates that with distance from the equator to the north or south it decreases, as the angle of incidence of the sun's ray decreases.

The degree of heating of the earth's surface is also influenced by the fact that the earth's axis is inclined to the orbital plane, along which the Earth makes a full revolution around the Sun, at an angle of 66.5° and is always directed with its northern end towards the North Star.

Let's imagine that the Earth, moving around the Sun, has an earthly axis perpendicular to the plane of the orbit of rotation. Then the surface at different latitudes would receive a constant amount of heat throughout the year, the angle of incidence of the sun's ray would be constant all the time, day would always be equal to night, and there would be no change of seasons. At the equator, these conditions would differ little from the present ones. It has a significant influence on the heating of the earth's surface, and therefore on the entire tilt of the earth's axis, precisely in temperate latitudes.

During the year, that is, during the entire revolution of the Earth around the Sun, four days are especially noteworthy: March 21, September 23, June 22, December 22.

The tropics and polar circles divide the Earth's surface into zones that differ in solar illumination and the amount of heat received from the Sun. There are 5 light zones: the northern and southern polar ones, which receive little light and heat, the zone with a hot climate and the northern and southern belt, which receive more light and heat than polar ones, but less than tropical ones.

So, in conclusion, we can draw a general conclusion: uneven heating and illumination of the earth’s surface is associated with the sphericity of our Earth and with the inclination of the earth’s axis to 66.5° to the orbit around the Sun.

With the help of this video lesson, you can independently study the topic “Distribution of sunlight and heat.” First, discuss what determines the change of seasons, study the pattern of the Earth’s annual rotation around the Sun, paying special attention to the four dates that are most notable in terms of solar illumination. Then you will find out what determines the distribution of sunlight and heat on the planet and why this happens unevenly.

Rice. 2. Illumination of the Earth by the Sun ()

In winter, the southern hemisphere of the Earth is better illuminated, in summer - the northern.

Rice. 3. Scheme of the annual rotation of the Earth around the Sun

Solstice ( summer solstice and winter solstice) - moments when the height of the Sun above the horizon at noon is greatest (summer solstice, June 22) or lowest (winter solstice, December 22). In the southern hemisphere, the opposite is true. On June 22, the northern hemisphere experiences the highest solar illumination, day longer than the night, there is a polar day above the polar circles. In the southern hemisphere, again, the opposite is true (i.e., all this is typical for December 22).

Arctic Circles (Arctic Circle and Antarctic Circle) - parallels with northern and southern latitudes, respectively, are about 66.5 degrees. North of the Arctic Circle and south of the Antarctic Circle experience polar day (summer) and polar night (winter). The area from the Arctic Circle to the Pole in both hemispheres is called the Arctic. Polar day - the period when the Sun in high latitudes does not fall below the horizon around the clock.

polar night - the period when the Sun in high latitudes does not rise above the horizon around the clock - a phenomenon opposite to the polar day, observed simultaneously with it at the corresponding latitudes of the other hemisphere.

Rice. 4. Scheme of illumination of the Earth by the Sun by zones ()

Equinox (spring equinox and autumn equinox) - moments when the sun's rays touch both poles and fall vertically on the equator. The spring equinox occurs on March 21, the autumn equinox on September 23. On these days, both hemispheres are illuminated equally, day is equal to night,

The main reason for changes in air temperature is a change in the angle of incidence of the sun's rays: the more vertically they fall on the earth's surface, the better they warm it up.

Rice. 5. Angles of incidence of solar rays (at Sun position 2, the rays warm up the earth’s surface better than at position 1) ()

On June 22, the sun's rays fall most vertically onto the Earth's northern hemisphere, thereby warming it to the greatest extent.

Tropics - The Northern Tropic and Southern Tropic are parallels, respectively, with northern and southern latitudes of about 23.5 degrees. On one of the days of the solstice, the Sun is at its zenith at noon above them.

The tropics and polar circles divide the Earth into zones of illumination. Light belts - parts of the Earth's surface limited by the tropics and polar circles and differing in lighting conditions. The warmest light zone is tropical, the coldest is polar.

Rice. 6. Earth's illumination belts ()

The sun is the main luminary, the position of which determines the weather on our planet. The moon and other cosmic bodies have indirect influence.

Salekhard is located on the Arctic Circle line. In this city there is an obelisk to the Arctic Circle.

Rice. 7. Obelisk to the Arctic Circle ()

Cities where you can watch the polar night: Murmansk, Norilsk, Monchegorsk, Vorkuta, Severomorsk, etc.

Homework

Paragraph 44.

1. Name the days of the solstices and the days of the equinoxes.

Bibliography

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