Geographic distribution of air temperature near the earth's surface. What determines the temperature distribution in Russia in summer? in winter? What is air mass

The sun's rays, when passing through transparent substances, heat them very weakly. This is due to the fact that direct sunlight practically does not heat the atmospheric air, but strongly heats the earth's surface, which is capable of transferring thermal energy to the adjacent air layers. As it warms up, the air becomes lighter and rises higher. In the upper layers, warm air mixes with cold air, giving it part of the thermal energy.

The higher the heated air rises, the more it cools. The air temperature at an altitude of 10 km is constant and is -40-45 ° C.

A characteristic feature of the Earth's atmosphere is a decrease in air temperature with altitude. The temperature sometimes rises as the altitude rises. The name of this phenomenon is temperature inversion (temperature permutation).

Temperature change

The appearance of inversions can be caused by the cooling of the earth's surface and the adjacent air layer in a short period of time. This is also possible when dense cold air moves from mountain slopes to valleys. During the day, the air temperature is constantly changing. During the daytime, the earth's surface heats up and heats up the lower air layer. At night, along with the cooling of the earth, the air is cooled. It is cooler at dawn and warmer in the afternoon.

There is no daily temperature fluctuation in the equatorial zone. Nighttime and daytime temperatures are the same. The daily amplitudes on the coasts of seas, oceans and above their surface are insignificant. But in the desert zone, the difference between night and day temperatures can reach 50-60 ° C.

In the temperate zone, the maximum amount of solar radiation on Earth falls on the days of the summer solstices. But the hottest months are July in the Northern Hemisphere and January in the Southern. This is due to the fact that despite the fact that solar radiation is less intense during these months, a huge amount of thermal energy is given off by the highly heated earth's surface.

The annual temperature range is determined by the latitude of a particular area. For example, at the equator it is constant at 22-23 ° C. The highest annual amplitudes are observed in the mid-latitude regions and in the interior of the continents.

Any terrain is also characterized by absolute and average temperatures. Absolute temperatures are determined through long-term observations at meteorological stations. The hottest region on Earth is the Libyan Desert (+58 ° C), and the coldest one is Vostok Station in Antarctica (-89.2 ° C).

Average temperatures are established when calculating the arithmetic mean values ​​of several thermometer indicators. This is how the average daily, average monthly and average annual temperatures are determined.

In order to find out how heat is distributed on the Earth, temperature values ​​are plotted on a map and dots with the same values ​​are connected. The resulting lines are called isotherms. This method allows you to identify certain patterns in the distribution of temperatures. Thus, the highest temperatures are recorded not at the equator, but in tropical and subtropical deserts. A decrease in temperatures from the tropics to the poles in two hemispheres is characteristic. Taking into account the fact that in the Southern Hemisphere water bodies occupy a larger area than land, the temperature amplitudes between the hottest and coldest months are less pronounced there than in the Northern.

According to the location of isotherms, seven thermal zones are distinguished: 1 hot, 2 moderate, 2 cold, 2 permafrost zones.

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Heat turnover, one of the climate-forming processes, describes the processes of receiving, transferring, transferring and losing heat in the earth-atmosphere system. The peculiarities of heat circulation processes determine the temperature regime of the area. The thermal regime of the atmosphere is primarily due to the heat exchange between atmospheric air and the environment. In this case, the environment is understood to mean outer space, neighboring masses and especially the earth's surface. Heat exchange with the earth's surface by molecular and turbulent heat conduction is of decisive importance for the thermal regime of the atmosphere.

The distribution of air temperature over the globe depends on the general conditions of the influx of solar radiation at latitudes ( influence of latitude), from the distribution of land and sea, which absorb radiation in different ways and heat up in different ways ( underlying surface influence), and from air currents carrying air from one area to another ( influence of atmospheric circulation).

As follows from Fig. 1.9, the least deviations from latitudinal circles on the map of average annual temperatures for sea level. In winter, the continents are colder than the oceans, in summer they are warmer; therefore, in average annual values, the opposite deviations of isotherms from the zonal distribution are partially mutually compensated. On the map of the average annual temperature on both sides of the equator - in the tropics there is a wide zone where the average annual temperatures are above + 25 ° C. Inside the zone, heat islands are outlined by closed isotherms over North Africa, India and Mexico, where the average annual temperature is above + 28 ° C. There are no heat islands over South America, South Africa and Australia. However, over these continents, isotherms sag to the south, forming "tongues of heat" in which high temperatures spread further towards high latitudes than over the oceans. Thus, the tropics of the continents are warmer than the tropics of the oceans (we are talking about the average annual air temperature above them).

Rice. 1.9. Distribution of the average annual air temperature at sea level (ºС) (Khromov S.P., Petrosyants M.A., 2006)

In extratropical latitudes, the isotherms deviate less from the latitudinal circles, especially in the Southern Hemisphere, where the underlying surface in the middle latitudes is an almost continuous ocean. In the Northern Hemisphere, at middle and high latitudes, more or less noticeable deviations of isotherms to the south over the continents of Asia and North America are observed. This means that, on average, the continents in these latitudes are somewhat colder than the oceans. The warmest places on the Earth in the average annual distribution are observed on the coasts of the southern part of the Red Sea. In Massawa (Eritrea, 15.6 ° N, 39.4 ° E), the average annual temperature at sea level is +30 ° C, and in Hodeidah (Yemen, 14.6 ° N, 42.8 ° E). ) 32.5 ° C. The coldest region is East Antarctica, where in the center of the plateau average annual temperatures are of the order of -50¸-55 ° C (Klimatologiya, 1989).

The temperature decreases from the equator to the poles in accordance with the distribution of the radiation balance of the earth's surface.

The isotherms on the maps do not completely coincide with the latitudinal circles, as well as the isolines of the radiation balance, i.e. are not zoned. They deviate especially strongly from zoning in the Northern Hemisphere, where the influence of the dismemberment of the earth's surface on land and sea is clearly visible. In addition, disturbances in temperature distribution are associated with the presence of snow or ice cover, mountain ranges, and warm and cold ocean currents.

The distribution of temperature is also influenced by the characteristics of the general circulation of the atmosphere, since the temperature in each given place is determined not only by the conditions of the radiation balance in this place, but also by the advection of air from other regions. For example, in the western part of Eurasia, temperatures are higher in winter and lower in summer than in the east, precisely because, with the prevailing western direction of air currents from the west, masses of sea air from the Atlantic Ocean penetrate far into Eurasia.

Question 1. What determines the distribution of heat over the Earth's surface?

The distribution of air temperature above the Earth's surface depends on the following four main factors: 1) latitude, 2) the height of the land surface, 3) the type of surface, especially the location of land and sea, 4) heat transfer by winds and currents.

Question 2. In what units is the temperature measured?

In meteorology and in everyday life, the Celsius scale or degrees Celsius is used as a unit for measuring temperature.

Question 3. What is the name of the temperature measuring device?

Thermometer is a device for measuring air temperature.

Question 4. How does the air temperature change during the day, during the year?

The change in temperature depends on the rotation of the Earth around its axis and, accordingly, on the change in the amount of solar heat. Therefore, the air temperature rises or falls depending on the location of the Sun in the sky. The change in air temperature throughout the year depends on the position of the Earth in orbit as it rotates around the Sun. In summer, the earth's surface heats up well due to direct sunlight.

Question 5. Under what conditions at a particular point on the surface of the Earth will the air temperature remain always constant?

If the Earth does not revolve around the sun and its axis and there is no air transfer by winds.

Question 6. By what pattern does the air temperature change with height?

When rising above the Earth's surface, the air temperature in the troposphere decreases by 6 C for each kilometer of rise.

Question 7. What is the relationship between the air temperature and the geographical latitude of the place?

The amount of light and heat received by the earth's surface gradually decreases in the direction from the equator to the poles due to a change in the angle of incidence of the sun's rays.

Question 8. How and why does the air temperature change during the day?

The sun rises in the east, rises higher and higher, and then begins to sink until it sets over the horizon until the next morning. The daily rotation of the Earth leads to the fact that the angle of incidence of the sun's rays on the Earth's surface changes. This means that the level of heating of this surface also changes. In turn, the air that heats up from the surface of the Earth receives different amounts of heat during the day. And at night, the amount of heat received by the atmosphere is even less. This is the reason for the diurnal variability. During the day, the air temperature rises from dawn to two in the afternoon, and then begins to drop and reaches a minimum one hour before dawn.

Question 9. What is the temperature range?

The difference between the highest and lowest air temperatures over a period of time is called the temperature amplitude.

Question 11. Why is the highest temperature observed at 14 o'clock, and the lowest - in the "pre-dawn hour"?

Because at 14 o'clock the Sun heats the earth as much as possible, and in the predawn hour the Sun has not yet risen, and during the night the temperature dropped all the time.

Question 12. Is it always possible to limit oneself to knowledge only about the average values ​​of temperature?

No, as in certain situations it is necessary to know the exact temperature.

Question 13. For what latitudes and why are the lowest average air temperatures typical?

For polar latitudes, since the sun's rays reach the surface at the smallest angle.

Question 14. For which latitudes and why are the highest average air temperatures typical?

The highest average air temperatures are typical for the tropics and the equator, since there is the greatest angle of incidence of sunlight.

Question 15. Why does the air temperature decrease with height?

Because the air warms up from the Earth's surface when it has a positive temperature and the higher the air layer is, the less it warms up.

Question 16. What month of the year do you think has the lowest average air temperatures in the Northern Hemisphere? In the Southern Hemisphere?

January is on average the coldest month of the year in most of the Earth's Northern Hemisphere, and the warmest month of the year in most of the Southern Hemisphere. June is on average the coldest month of the year in most of the Southern Hemisphere.

Question 17. At which of the following parallels the height of the midday sun will be greatest: 20 ° N. latitude, 50 ° S sh., 80 p. NS.?

Question 18. Determine the air temperature at an altitude of 3 km, if at the surface of the Earth it is +24 ° C?

tн = 24-6.5 * 3 = 4.5 ºС

Question 19. Calculate the average temperature from the data presented in the table.

(5+0+3+4+7+10+5) : 6 = 4,86; (-3 + -1) : 2 = -2; 4,86 - 2 = 2,86

Answer: average temperature = 2.86 degrees.

Question 20. Using the tabular data given in task 2, determine the temperature amplitude for the specified period.

The temperature amplitude for the specified period will be 13 degrees.

There is a source of heat and light in our solar system - a star called the Sun. Considering the question of what are the regularities of the distribution of air temperature on Earth, one cannot do without this very object, without mentioning water and atmospheric pressure. All these constituents make up the climate.

As you know, the Sun is far enough from our planet, but it emits such a powerful stream of heat and light that it easily warms up the Earth, albeit rather unevenly.

Distribution of light and heat

The uneven distribution of heat on our planet occurs because of the spherical. Naturally, moving around the Sun, it is illuminated only from one side. In addition, in some areas, beams of light fall vertically, which guarantees good heating of the air. These sites are located at the equator. But for the same reason, only a limited area warms up.

Yet, what are the regularities in the distribution of air temperature on Earth? Consider a more significant factor - the fall of the sun's rays. Areas closer to the equator warm up better. The closer to the poles, the lower the air temperature. But the paradox: the rays are the same in power both at the equator and at the poles, the reason for the different temperatures is the angle of incidence of the rays on the Earth's surface. If it is large, then it travels a long distance, the majority is simply scattered in the troposphere, as a result, not reaching the surface of the planet.

Another factor is the tilt of the earth's axis. If this were not the case, then there would be no change of seasons, day and night would be equal in time, the same air temperature was constantly observed.

Let's summarize this point. What are the patterns of air temperature distribution on Earth? The closer to the equator, the warmer. So far, we have identified two components of the formation of the climate: the tilt of the axis and the incidence of the rays, more precisely, the angle.

Relationship between water and air temperature

The hydrosphere and the atmosphere are in very close contact, or more precisely, they are They dictate the patterns of distribution of heat and moisture on our planet. What kind of relationship can be observed? It's simple: territories dominated by land are prone to cold snaps. The current situation is as follows: at the moment, there is an uneven distribution of water resources, which can cause the onset of glaciation.

It is important to know that land and air heats up quite quickly in the daytime, but they lose heat just as instantly at night. We do not really feel these changes due to the layers of the troposphere, which trap heat. For example, let's take our satellite Moon. It receives about the same amount of solar energy as the Earth, but given that the Moon does not have an atmosphere, it heats up by more than a hundred degrees during the day, and cools down to minus one hundred and sixty at night.

What are the patterns of air temperature distribution on Earth, we have considered, now we turn to the issue of moisture distribution. As we know, water from reservoirs evaporates all the time, mainly in the oceans. Then this air rushes over the continents, cooling at the same time, as a result, precipitation falls (rain or snow), partly the water returns to the ocean. This is what the hydrological cycle looks like.

Distribution of air temperature and atmospheric pressure

In total, our planet has three belts of low and four belts of high atmospheric pressure. We propose to figure out how they formed. It is important to note that air masses can move both horizontally and vertically.

As mentioned earlier, at the equator, the air heats up quite strongly, which leads to its expansion, it becomes lighter and rises. In this regard, low atmospheric pressure is formed at the earth's surface at the equator and in the approximate regions.

At the poles, we can observe the opposite phenomenon, this is due to the fact that the air is cold and heavy. This creates high atmospheric pressure.

Air temperature and altitude

In addition to everything that was said earlier, the patterns of air temperature distribution on Earth can be considered from the other side. Regardless of in what zone and at what latitude the territory is located, regardless of atmospheric pressure, the air temperature gradually decreases with an increase in altitude.

The very first, closest layer to the earth's surface is the troposphere, it extends upward to a height of ten to eighteen kilometers. And the temperature in it drops with every hundred meters by about six-tenths of a degree. This is followed by a layer of the stratosphere. At first, the temperature in it is unchanged, but gradually begins to rise.

Geographic distribution of air temperature near the earth's surface

1. Considering the maps of the long-term average distribution of air temperature at sea level for individual calendar months and for the whole year, we find in this distribution a number of regularities that indicate the influence of geographic factors.

This is primarily the influence of latitude. The temperature generally decreases from the equator to the poles in accordance with the distribution of the radiation balance of the earth's surface. This decrease is especially significant in each hemisphere in winter, because near the equator the temperature changes little in the annual course, and at high latitudes in winter it is much lower than in summer.

However, the isotherms on the maps do not completely coincide with the latitudinal circles, as well as the isolines of the radiation balance. They deviate especially strongly from zoning in the northern hemisphere. This clearly shows the influence of the dismemberment of the earth's surface on land and sea, which we will consider in more detail later. In addition, disturbances in temperature distribution are associated with the presence of snow or ice cover, mountain ranges, and warm and cold ocean currents. Finally, the distribution of temperature is also influenced by the characteristics of the general circulation of the atmosphere. After all, the temperature in each given place is determined not only by the conditions of the radiation balance in this place, but also by the transfer of air from other regions. For example, the lowest temperatures in Eurasia are found not in the center of the continent, but are strongly shifted to its eastern part. In the western part of Eurasia, temperatures are higher in winter and lower in summer than in the eastern part, precisely because, with the prevailing western direction of air currents from the west, masses of sea air from the Atlantic Ocean penetrate far into Eurasia.

2. Year. Deviations from latitudinal circles are lowest on the map of annual mean temperatures for sea level (Map XI). In winter, the continents are colder than the oceans, and in summer they are warmer; therefore, in average annual values, the opposite deviations of isotherms from the zonal distribution are partially mutually compensated. On the average annual map, we find on both sides of the equator in the tropics a wide zone where the average annual temperatures are above 25 ° C. Inside this zone, heat islands are outlined by closed isotherms over North Africa and, less significant in size, over India and Mexico, where the average annual temperature is above 28 ° C. There are no such warm islands over South America, South Africa and Australia; however, over these continents, the isotherms sag to the south, forming<языки тепла>: High temperatures spread further towards higher latitudes here than over the oceans. We see, therefore, that in the tropics, on average, the continents are warmer than the oceans (we are talking about the air temperature above them).

In extratropical latitudes, the isotherms deviate less from the latitudinal circles, especially in the southern hemisphere, where the underlying surface in the middle latitudes is an almost continuous ocean. But in the northern hemisphere, we still find in the middle and high latitudes more or less noticeable deviations of the isotherms to the south over the continents of Asia and North America. This means that, on average, the continents in these latitudes are somewhat colder than the oceans.

The warmest places on the Earth on average are located on the coasts of the southern part of the Red Sea. In Massawa (Eritrea, 15.6 ° N, 39.4 ° E), the average annual temperature at sea level is 30 ° C, and in Hodeidah (Yemen, 14.6 ° N, 42, 8 ° E) even 32.5 ° C. The coldest region is East Antarctica, where in the center of the plateau average annual temperatures are -50 ... ... 55 C. 1

3. January (map XII). On the maps for January and July (the central months of winter and summer), the deviations of the isotherms from the zonal direction are much larger. True, in the tropics of the northern hemisphere, January temperatures on the oceans and continents are quite close to each other (under each given parallel). Isotherms pass not deviating particularly strongly from the latitudinal circles. Inside the tropics, the temperature varies little with latitude. But outside the tropics in the northern hemisphere, it rapidly decreases towards the pole. Isotherms are very dense here in comparison with the July map. In addition, we find over the cold continents of the northern hemisphere in extratropical latitudes, pronounced troughs of isotherms in the direction to the south, and over warmer oceans - to the north: tongues of cold and warmth.

Map XI. Distribution of the average annual air temperature at sea level (° С).

Especially significant is the deflection of isotherms to the north over the warm waters of the North Atlantic, over the eastern part of the ocean, where the Atlantic Current branch of the Gulf Stream passes. We see here a striking example of the influence of ocean currents on temperature distribution. The zero isotherm in this region of the North Atlantic penetrates the Arctic Circle (in winter!). The sharp thickening of isotherms off the coast of Norway speaks of another factor - the influence of coastal mountains, behind which cold air accumulates in the depths of the peninsula. This enhances the contrast between temperatures over the Gulf Stream and the Scandinavian Peninsula. A similar influence of the Rocky Mountains can be seen in the Pacific coast of North America. But the thickening of isotherms on the east coast of Asia is mainly associated with the nature of atmospheric circulation: in January, warm air masses from the Pacific Ocean almost do not reach the Asian mainland, and cold continental air masses quickly warm up over the ocean.

Over northeast Asia and over Greenland, we even find closed isotherms that outline the islands of cold. In the first area, between Lena and Indigirka, the average January temperatures reach -48 ° С, and at the terrain level -50 ° С and below, the absolute minimums are even -70 ° С. This is the area of ​​the Yakut cold pole. The lowest temperatures are observed in Verkhoyansk (67.5 ° N, 133.4 ° E) and Oymyakon (63.2 ° N, 143.1 ° E).

Northeast Asia in winter has very low temperatures throughout the troposphere. But the occurrence of extremely low temperature minimums near the earth's surface is facilitated in these areas by orographic conditions: these low temperatures are observed in depressions or valleys surrounded by mountains, where air stagnation is created in the lower layers.

The second pole of cold in the northern hemisphere is Greenland. The average January temperature at the terrain level here drops to -55 ° С, and the lowest temperatures in the center of the island seem to reach the same low values ​​as in Yakutia (-70 ° С). the cold pole is not as well expressed as the Yakut pole, due to the high altitude of the Greenland plateau. A significant difference between the Greenland cold pole and the Yakut pole is that in summer the temperatures above the Greenland ice are very low: the average July temperature at the terrain level is up to -15 ° C. In Yakutia, summer temperatures are comparatively high: of the same order as under the corresponding latitudes in Europe. Therefore, the Greenlandic cold pole is constant, and the Yakut pole is only winter. The area of ​​Baffin's Land is also very cold.

Map XII. Distribution of mean monthly air temperature at sea level in January (° С).

In the region of the North Pole, the average temperature in winter is higher than in Yakutia and Greenland, since cyclones relatively often bring air masses here from the Atlantic and Pacific oceans.

In the southern hemisphere, it is summer in January. The distribution of temperature in the tropics of the southern hemisphere over the oceans is extremely uniform. But over the continents in South Africa, South America and especially in Australia, there are well-defined islands of heat with average temperatures up to 34 ° C in Australia. The maximum temperatures in Australia reach 55 ° C. In South Africa, temperatures at the terrain level are not so high due to the significant elevations of the terrain above sea level: the absolute maximum temperature does not exceed 45 ° C.

In the extratropical latitudes of the southern hemisphere, the temperature drops more or less rapidly to about the 50th parallel. Then there is a wide zone with uniform temperatures close to 0-5 ° С, to the very shores of Antarctica. In the depths of the icy continent, the temperature drops to -35 ° C. Attention should be paid to the tongues of cold over the oceans off the western coasts of South America and South Africa, associated with cold ocean currents.

4. July (map XIII). In July, in the tropics and subtropics of the northern, now summer hemisphere, heat islands with closed isotherms are well expressed over North Africa, Arabia, Central Asia and Mexico. It should be noted that both Mexico and Central Asia have high elevations above sea level, and temperatures at local level are not as high as at sea level.

Average July temperatures in the Sahara reach 40 ° C (somewhat lower at the local level). The absolute maximum temperature in North Africa reaches 58 ° C (Azizia in the Libyan Desert, south of the city of Tripoli; 32.4 ° N, 13.0 ° E). Slightly lower, 57 ° С, the absolute maximum temperature in a deep depression among the mountains in California, in the Valley

Map XIII. Distribution of average monthly air temperature at sea level in July (° С).

Rice. 28. Dependence of the average air temperature near the earth's surface on the geographical latitude. 1 - January, 2 - July, 3 - year.

Death (36.5 ° N, 117.5 ° W). In the USSR, the absolute maximum temperature in Turkmenistan reaches 50 ° C.

The air is colder over the oceans than over the continents, both in the tropics and in extratropical latitudes.

There are no islands of warmth and cold with closed isotherms in the extratropical latitudes of the northern hemisphere, but there are noticeable deflections of the isotherms to the equator over the oceans and to the pole over the continents. We also see the trough of isotherms to the south over Greenland with its permanent ice cover. Low temperatures over Greenland are, of course, more pronounced at the local level, where the average temperature in the center of the island is below -15 ° C.

Interesting is the thickening of isotherms off the coast of California, associated with the proximity of overheated deserts and the cold California current. The average July temperature on the coast of Northern California is about 16 ° C, and in the inland desert up to 32 ° C and higher. It should also be noted the tongues of cold over the Okhotsk and Bering Seas and over Lake Baikal. The temperature over the latter in July is lowered by about 5 ° C compared to the regions located 100 km away from the lake.

It is winter in the southern hemisphere in July and there are no closed isotherms over the continents. The influence of cold currents off the western coasts of America and Africa is also felt in July (tongues of cold). But in general, isotherms are especially close to latitudinal circles. In extratropical latitudes, the temperature drops rather quickly towards Antarctica. On the outskirts of the continent, it reaches -15 ...- 35 ° С, and in the center of East Antarctica, the average temperatures are close to -70 ° С. In some cases, temperatures are observed below -80 ° C, the absolute minimum is below -88 ° C (Vostok station, 72.1 ° S, 96.6 ° E, altitude 3420 m). This is the pole of cold not only for the southern hemisphere, but for the entire globe.