How temperatures are distributed over the surface of the earth. What determines the temperature distribution in Russia in summer? in winter? What pattern does the map data confirm?

Geographical 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 entire year, we find a number of patterns in this distribution that indicate the influence of geographical factors.

This is primarily the effect 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 varies 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 quite 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 division of the earth's surface on land and sea, which we will consider in more detail later. In addition, perturbations in the temperature distribution are associated with the presence of snow or ice cover, mountain ranges, warm and cold ocean currents. Finally, the characteristics of the general circulation of the atmosphere also influence the temperature distribution. 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 areas. For example, the lowest temperatures in Eurasia are not found 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 westerly direction of air currents, masses of sea air from the Atlantic Ocean penetrate far into Eurasia from the west.

2. Year. Deviations from latitudinal circles are smallest on the map of mean annual temperatures for sea level (map XI). In winter, the continents are colder than the oceans, and warmer in summer; therefore, in the average annual values, the opposite deviations of the 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. Within this zone, heat islands over North Africa and, less significant in size, over India and Mexico, where the average annual temperature is above 28 ° C, are outlined by closed isotherms. There are no such heat islands over South America, South Africa, and Australia; however, over these continents, the isotherms bend to the south, forming<языки тепла>: high temperatures spread here further towards high latitudes than over the oceans. Thus, we see that in the tropics, on average, the continents are warmer than the oceans (we are talking about the air temperature above them).

At extratropical latitudes, isotherms deviate less from latitudinal circles, especially in the southern hemisphere, where the underlying surface at 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 an average annual basis, the continents in these latitudes are somewhat colder than the oceans.

The warmest places on the Earth in the average annual lie 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 Hodeida (Yemen, 14.6°N, 42, 8°E) even 32.5°C. The coldest region is East Antarctica, where in the center of the plateau the 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 isotherms from the zonal direction are much larger. True, in the tropics of the northern hemisphere, the January temperatures on the oceans and continents are quite close to each other (under each given parallel). Isotherms are not particularly strongly deviating from the latitudinal circles. Inside the tropics, the temperature varies little with latitude. But outside the tropics in the northern hemisphere, it quickly decreases towards the pole. Isotherms pass here very densely in comparison with the July map. In addition, we find over the cold continents of the northern hemisphere in extratropical latitudes pronounced deflections of isotherms in the direction to the south, and over warmer oceans - to the north: tongues of cold and heat.

Map XI. Distribution of mean annual air temperature at sea level (°C).

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 branch of the Gulf Stream passes - the Atlantic Current. We see here a vivid example of the influence of ocean currents on temperature distribution. The zero isotherm in this region of the North Atlantic penetrates beyond 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. In the Pacific Coast region of North America, a similar influence of the Rocky Mountains can be seen. But the thickening of isotherms on the east coast of Asia is mainly due to 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 the northeast of Asia and over Greenland we even find closed isotherms delineating islands of cold. In the first region, between Lena and Indigirka, the average January temperatures reach -48°C, and at the level of the area -50°C and below, the absolute minimums are even -70°C. This is the region of the Yakut pole of cold. The lowest temperatures are observed in Verkhoyansk (67.5°N, 133.4°E) and Oymyakon (63.2°N, 143.1°E).

Northeast Asia has very low temperatures throughout the troposphere in winter. But the occurrence of extremely low temperature minima 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 cold pole in the northern hemisphere is Greenland. The average January temperature at the local level here drops to -55 ° C, and the lowest temperatures in the center of the island apparently reach the same low values ​​as in Yakutia (-70 ° C). On the map of isotherms for sea level, this Greenlandic the cold pole is not as well pronounced as the Yakut one, due to the high altitude of the Greenland plateau. The essential difference between the Greenland pole of cold and the Yakut one is that in summer the temperatures over the ice of Greenland are very low: the average July temperature at the local level is up to -15°C. In Yakutia, on the other hand, summer temperatures are relatively high: of the same order as under the corresponding latitudes in Europe. Therefore, the Greenland pole of cold is permanent, and the Yakut one is only winter. The area of ​​Baffin Island is also very cold.

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

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

January is summer in the southern hemisphere. The distribution of temperature in the tropics of the southern hemisphere over the oceans is very even. But over the continents in South Africa, South America, and especially in Australia, well-defined heat islands are outlined with average temperatures up to 34 ° C in Australia. Maximum temperatures reach 55 °C in Australia. In South Africa, ground-level temperatures are not as high due to the high elevation of the ground above sea level: absolute temperature maxima do 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 comes a wide zone with uniform temperatures close to 0-5 ° C, to the very coast of Antarctica. In the depths of the icy continent, the temperature drops to -35°C. Attention should be paid to 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 over North Africa, Arabia, Central Asia and Mexico are well expressed. 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 (slightly 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). A little lower, 57°C, is the absolute maximum temperature in a deep depression among the mountains in California, in the Valley

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

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

Deaths (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 heat and cold with closed isotherms in the extratropical latitudes of the northern hemisphere, but the isotherm troughs are noticeable towards the equator over the oceans and towards the pole over the continents. We also see the deflection of isotherms to the south over Greenland with its permanent ice cover. The low temperatures over Greenland are, of course, better expressed at the level of the area, where the average temperature in the center of the island is below -15 °C.

The concentration of isotherms off the coast of California is interesting, 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 desert inland up to 32 ° C and above. It should also be noted tongues of cold over the Sea of ​​Okhotsk and the Bering Sea and over Baikal. The temperature over the latter in July is lower by about 5°C compared to the areas 100 km away from the lake.

In the southern hemisphere, it is winter 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 decreases quite rapidly towards Antarctica. On the outskirts of the mainland, it reaches -15 ... -35 °С, and in the center of East Antarctica, the average temperatures are close to -70 °С. In some cases, temperatures below -80 °C are observed, 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 of the southern hemisphere, but of the entire globe.

Temperature is a very variable characteristic of the atmosphere, it varies in time and space. Changes in temperature over time are associated with the daily course of the radiation balance, but the temperature also changes during the day due to the action of other factors, for example, advection of air masses, which causes non-periodic changes in air temperature.

There are certain and significant differences in the heating of the surface layers of soil and water, which affect the daily temperature course, as well as the seasonal course. So, the surface of the water heats up relatively little, but a thick layer of water warms up. The surface of the soil heats up very strongly, but heat is transferred deep into the soil weakly. As a result, the ocean gives off a lot of heat at night, while the soil surface cools very quickly.

These differences are also reflected in the seasonal course of surface temperature. However, seasonal temperature changes are caused mainly by the change of seasons, which is especially evident in the temperate and polar zones. At the same time, during the cold season, the water constantly gives off the accumulated heat (whereas the soil does not store so much heat), therefore, in the cold season, over the ocean, as well as over areas subject to its direct influence, it is warmer than over land not subject to the influence of the sea. air.

Considering maps of the long-term average distribution of air temperature at sea level for individual calendar months and for the entire year, we find a number of patterns in this distribution that indicate the influence of geographical factors. This is primarily the effect 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 varies little in the annual course, while at high latitudes it is much lower in winter than in summer.

However, the isotherms on the maps do not quite coincide with the latitudinal circles, as well as the isolines of the radiation balance (Fig. 6.8). They deviate especially strongly from zoning in the northern hemisphere. This clearly shows the influence of the division of the earth's surface into land and sea. In addition, perturbations in the temperature distribution are associated with the presence of snow or ice cover, mountain ranges, and ocean currents. Finally, the characteristics of the atmospheric circulation also affect the temperature distribution. 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 areas. For example, the lowest temperatures in Eurasia are not found 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 westerly direction of air currents, masses of sea air from the Atlantic Ocean penetrate far into Eurasia from the west.

Deviations from latitudinal circles are the smallest on the map of mean annual temperatures for sea level. In winter, the continents are colder than the oceans, and warmer in summer; therefore, in the average annual values, the opposite deviations of the 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. Within this zone, heat islands are outlined 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 heat islands over South America, South Africa, and Australia; however, over these continents, the isotherms bend to the south, forming "heat tongues": high temperatures spread here further towards high latitudes than over the oceans. Thus, in the tropics, on average, the continents are warmer than the oceans (we are talking about the air temperature above them).

At extratropical latitudes, isotherms deviate less from latitudinal circles, especially in the southern hemisphere, where the underlying surface at 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 an average annual basis, the continents in these latitudes are somewhat colder than the oceans.

Fig.6.8. Distribution of mean annual air temperature at sea level

The features of the temperature distribution in January and July also differ significantly (these months are usually used in climatology as a characteristic of winter and summer). Such maps are shown in Figures 6.9 and 6.10.

January is winter in the northern hemisphere. The deviations of the isotherms from the zonal direction are significant. Inside the tropics, the temperature varies little with latitude. But outside the tropics in the northern hemisphere, it quickly decreases towards the pole. Isotherms pass here very densely in comparison with the July map. In addition, we find over the cold continents of the northern hemisphere in extratropical latitudes pronounced deflections of isotherms in the direction to the south, and over warmer oceans - to the north: tongues of cold and heat.

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 branch of the Gulf Stream passes - the Atlantic Current. We see here a vivid example of the influence of ocean currents on temperature distribution. The zero isotherm in this region of the North Atlantic penetrates even beyond 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.

Fig.6.9. Distribution of mean monthly air temperature at sea level in January

Fig.6.10. Distribution of mean monthly air temperature at sea level in July

This enhances the contrast between temperatures over the Gulf Stream and the Scandinavian Peninsula. In the Pacific Coast region of North America, a similar influence of the Rocky Mountains can be seen. But the thickening of isotherms on the east coast of Asia is mainly due to 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 the northeast of Asia and over Greenland we even find closed isotherms, delineating a kind of islands of cold. In the first region, between Lena and Indigirka, the average January temperatures reach -50°C, this is the region of the Yakut pole of cold. Greenland is the second cold pole in the northern hemisphere. The average January temperature at the local level here drops to -55 ° C, and the lowest temperatures in the center of the island apparently reach the same low values ​​as in Yakutia. In the region of the North Pole, the average winter temperature is higher than in Yakutia and Greenland, since cyclones relatively often bring air masses here from the Atlantic and Pacific oceans.

January is summer in the southern hemisphere. The distribution of temperature in the tropics of the southern hemisphere over the oceans is very even. But over the continents in South Africa, South America and especially in Australia, well-defined heat islands are outlined with average temperatures up to 34 ° C in Australia. Maximum temperatures reach 55 °C in Australia. In South Africa, ground-level temperatures are not as high due to the high elevation of the ground above sea level: absolute temperature maxima do 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 comes a wide zone with uniform temperatures close to 0 °C, all the way to the shores of Antarctica. In the depths of the icy continent, the temperature drops to -35°C.

July is summer in the northern hemisphere. In July, in the tropics and subtropics of the northern, summer hemisphere, heat islands with closed isotherms over North Africa, Arabia, Central Asia and Mexico are well expressed.

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

In the southern hemisphere, it is winter 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 decreases quite rapidly towards Antarctica. In the center of East Antarctica, average temperatures are close to -70°C. In some cases, temperatures below -80°C are observed, the absolute minimum is below -88°C (Vostok station). This is the pole of cold not only of the southern hemisphere, but of the entire globe.

The difference between the average monthly temperatures of the warmest and coldest months is called the annual air temperature amplitude. In climatology, annual temperature amplitudes are considered, calculated from long-term average monthly temperatures.

The annual amplitude of air temperature primarily increases with geographic latitude. At the equator, the influx of solar radiation changes very little during the year; in the direction of the pole, the differences in the inflow of solar radiation between winter and summer increase, and at the same time, the annual amplitude of air temperature also increases. Over the ocean, far from the coast, this latitudinal change in the annual amplitude, however, is small.

Annual temperature amplitudes over land are much larger than over the sea (as well as daily amplitudes). Even over relatively small continental massifs of the southern hemisphere, they exceed 15°C, and under a latitude of 60° on the Asian mainland, in Yakutia, they reach 60°C (Fig. 6.11).

Fig.6.11 Distribution of the average annual air temperature amplitude

But small amplitudes are also observed in many areas over land, even far from the coastline, if air masses from the sea often come there, for example, in Western Europe. On the contrary, increased amplitudes are also observed over the ocean where air masses from the mainland often enter, for example, in the western parts of the oceans of the northern hemisphere. Therefore, the annual temperature amplitude depends not only on the nature of the underlying surface or on the proximity of a given place to the coastline. It depends on the frequency of air masses of marine and continental origin in a given place, i.e., on the conditions of the general circulation of the atmosphere.

Not only the seas, but also large lakes reduce the annual amplitude of air temperature and thereby soften the climate. In the middle of Lake Baikal, the annual amplitude of air temperature is 30 - 31 ° C, on its shores it is about 36 ° C, and under the same latitude on the river. Yenisei 42 °C.

Usually, the climate over the sea, characterized by small annual temperature amplitudes, is called maritime climate, and the climate over land with large annual temperature amplitudes - continental. The continentality of the climate should always be kept in mind, especially when describing the climatic characteristics of the area. Thus, Western Europe is characterized by a pronounced maritime climate (the influence of the air masses of the Atlantic). And Siberia, on the contrary, has a continental climate. Sometimes, to characterize continentality, the so-called. continental indexes.

The rays of the Sun, 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 layers of air. As it warms, the air becomes lighter and rises higher. In the upper layers, warm air mixes with cold air, giving it some of the heat 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 height. Sometimes there is an increase in temperature as altitude increases. The name of such a phenomenon is temperature inversion (permutation of temperatures).

Temperature change

The appearance of inversions may be due to 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 changes continuously. During the daytime, the earth's surface heats up and heats the lower layer of air. At night, along with the cooling of the earth, the air cools. It is coolest at dawn and warmest in the afternoon.

There is no diurnal temperature fluctuation in the equatorial zone. Night and day temperatures are the same. Diurnal amplitudes on the coasts of the 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 month is July in the Northern Hemisphere and January in the Southern. This is explained by 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 a very heated earth's surface.

The annual temperature amplitude is determined by the latitude of a certain area. For example, at the equator it is constant and is 22-23 ° C. The highest annual amplitudes are observed in the regions of middle latitudes and deep in the continents.

Absolute and average temperatures are also characteristic of any area. Absolute temperatures are determined through long-term observations at weather stations. The hottest area on Earth is the Libyan Desert (+58°C), and the coldest is Vostok Station in Antarctica (-89.2°C).

Average temperatures are set when calculating the arithmetic mean of several thermometer readings. This is how average daily, average monthly and average annual temperatures are determined.

In order to find out how heat is distributed on Earth, temperatures are plotted on a map and points 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. Given 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 Hemisphere.

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

Related content:

I am used to the climate in which I live, but still in the summer I want maximum warmth, and therefore I am going to the south of the country. In winter, I admire the beauty of snow-covered nature. In fact, the temperature in different regions of the country is very different. If in winter it snows almost everywhere, then in summer, if you move from north to south, the weather changes.

What factors determine the temperature distribution

If we take the entire territory of Russia, then even in regions that are located in the same latitudes, the climate can be very different. Here are the main reasons that affect the temperature distribution on the surface:

• relief features;
• proximity to or distance from the sea;
• circulation of air masses;
• distance from the equator.

I will give a few examples. The Ural Mountains trap moist air masses that are directed from the sea, so the climate in Siberia is continental. It has hot but short summers and harsh and long winters.

The sea on one side and the mountains on the other are the main factors that determine the subtropical climate in the south of the Krasnodar Territory.

In general, the climate is milder up to the Urals than to the east of these mountains.

How is the temperature distributed in Russia in summer and winter

Russia is characterized by a clear division of the year into different, pronounced seasons, as well as a large temperature difference.

Generally speaking, the temperature is distributed unevenly. Of course, if you move from south to north, the average annual or monthly temperature drops. If in the south it is hot and sunny all summer, then in the north there are only a few warm days.

For example, in Siberia, the temperature range is the largest in the country, because in summer it can be up to +40, and in winter the same amount, but with a minus sign. In the north, at the beginning of summer, the thermometer can drop below zero, while in the south they are already swimming in the sea with might and main.

Snow falls almost throughout the country in winter, and only in the south the climate is milder. The most severe climate is in the north of the Far East, where the average January temperature is -46 degrees Celsius.