What is latitudinal zonation? Latitudinal zoning
Some geographic terms have similar but not identical names. For this reason, people often get confused in their definitions, and this can fundamentally change the meaning of everything they say or write. Therefore, now we will find out all the similarities and differences between latitudinal zonality and altitudinal zonality in order to permanently get rid of the confusion between them.
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The essence of the concept
Our planet has the shape of a ball, which, in turn, is tilted at a certain angle relative to the ecliptic. This state of affairs caused the sunlight distributed unevenly over the surface.
In some regions of the planet it is always warm and clear, in others there are downpours, in others there is cold and constant frosts. We call this the climate, which changes depending on the distance or approach to.
In geography, this phenomenon is called "latitudinal zoning", since the change in weather conditions on the planet occurs precisely depending on latitude. Now we can make a clear definition of this term.
What is latitudinal zonality? This is a natural modification of geosystems, geographic and climatic complexes in the direction from the equator to the poles. In everyday speech, we often call such a phenomenon "climatic zones", and each of them has its own name and characteristic. Below will be given examples demonstrating latitudinal zonality, which will allow you to clearly remember the essence of this term.
Note! The equator, of course, is the center of the Earth, and all the parallels from it diverge towards the poles, as if in a mirror image. But due to the fact that the planet has a certain inclination relative to the ecliptic, the southern hemisphere is more illuminated than the northern one. Therefore, the climate on the same parallels, but in different hemispheres does not always coincide.
We figured out what zoning is and what are its features at the level of theory. Now let's remember all this in practice, just looking at the climate map of the world. So the equator is surrounded (sorry for the tautology) equatorial climate zone. The air temperature here does not change throughout the year, however, as does the extremely low pressure.
Winds at the equator are weak, but heavy rains are common. It rains every day, but due to the high temperature, the moisture quickly evaporates.
We continue to give examples of natural zonality, describing tropical belt:
- There are pronounced seasonal temperature changes, not as much rainfall as at the equator, and not as low pressure.
- In the tropics, as a rule, it rains for half a year, the second half is dry and hot.
Also in this case, there are similarities between the southern and northern hemispheres. The tropical climate is the same in both parts of the world.
The next step is a temperate climate, which covers most of the northern hemisphere. As for the south, there it stretches over the ocean, barely capturing the tail of South America.
The climate is characterized by the presence of four pronounced seasons, which differ from each other in temperature and rainfall. Everyone knows from school that the entire territory of Russia is located mainly in this natural zone, so each of us can easily describe all the weather conditions inherent in it.
The latter, the arctic climate, differs from all the others in record low temperatures, which practically do not change throughout the year, as well as poor rainfall. It dominates the poles of the planet, captures a small part of our country, the Arctic Ocean and all of Antarctica.
What influences natural zoning
Climate is the main determinant of the entire biomass of a particular region of the planet. Due to varying air temperature, pressure and humidity flora and fauna are formed, soils change, insects mutate. It is important that the color of human skin depends on the activity of the Sun, due to which the climate, in fact, is formed. Historically, this has been the case:
- the black population of the Earth lives in the equatorial zone;
- mulattoes live in the tropics. These racial families are the most resistant to bright sunlight;
- the northern regions of the planet are occupied by fair-skinned people who are used to spending most of their time in the cold.
From all of the above follows the law of latitudinal zonality, which is as follows: "The transformation of the entire biomass directly depends on climatic conditions."
Altitudinal zonality
Mountains are an integral part of the earth's relief. Numerous ridges, like ribbons, are scattered around the globe, some are high and steep, others are sloping. It is these uplands that we understand as areas of altitudinal zonation, since the climate here differs significantly from the plains.
The thing is that rising to the layers more distant from the surface, the latitude at which we remain is already has no effect on the weather. Changes in pressure, humidity, temperature. Based on this, a clear interpretation of the term can be given. The zone of altitudinal zoning is a change in weather conditions, natural zones and landscape as the height above sea level increases.
Altitudinal zonality
illustrative examples
To understand in practice how the zone of altitudinal zonation is changing, it is enough to go to the mountains. Rising higher, you will feel how the pressure drops, the temperature drops. The landscape will change before our eyes. If you started from the zone of evergreen forests, then with height they will grow into shrubs, later - into grass and moss thickets, and at the top of the cliff they will completely disappear, leaving bare soil.
Based on these observations, a law was formed that describes the altitudinal zonality and its features. When ascending to a great height the climate becomes colder and harsher, the animal and plant worlds become scarce, atmospheric pressure becomes extremely low.
Important! Soils located in the area of altitudinal zonality deserve special attention. Their metamorphoses depend on the natural zone in which the mountain range is located. If a we are talking about the desert, then as the height increases, it will be transformed into mountain-chestnut soil, later - into black soil. After that, a mountain forest will appear on the way, and behind it - a meadow.
Mountain ranges of Russia
Special attention should be paid to the ridges, which are located in their native country. The climate in our mountains directly depends on their geographical location, so it is easy to guess that he is very severe. Let's start, perhaps, with the region of altitudinal zonality of Russia in the region of the Ural Range.
At the foot of the mountains there are birch and coniferous forests that are undemanding to heat, and as the height increases, they turn into moss thickets. The Caucasian Range is considered high, but very warm.
The higher we climb, the greater the amount of precipitation becomes. At the same time, the temperature drops slightly, but the landscape changes completely.
Another zone with high zonality in Russia is the Far Eastern regions. There, at the foot of the mountains, cedar thickets spread, and the tops of the rocks are covered with eternal snow.
Natural zones latitudinal zonality and altitudinal zonality
Natural zones of the Earth. Geography Grade 7
Conclusion
Now we can find out what are the similarities and differences in these two terms. Latitudinal zonality and altitudinal zonality have something in common - this is a change in climate, which entails a change in the entire biomass.
In both cases, weather conditions change from warmer to colder, pressure is transformed, and fauna and flora are depleted. What is the difference between latitudinal zonality and altitudinal zonality? The first term has a planetary scale. Due to it, the climatic zones of the Earth are formed. But the altitudinal zonality is climate change only within a certain relief- mountains. Due to the fact that the height above sea level increases, weather conditions change, which also entail the transformation of the entire biomass. And this phenomenon is already local.
Due to the spherical shape of the Earth and the change in the angle of incidence of the sun's rays on the earth's surface. In addition, latitudinal zonality also depends on the distance to the Sun, and the mass of the Earth affects the ability to hold the atmosphere, which serves as a transformer and redistributor of energy.
Of great importance is the inclination of the axis to the plane of the ecliptic, this determines the unevenness of the flow solar heat by seasons, and the daily rotation of the planet causes the deviation of air masses. The result of the difference in the distribution of the radiant energy of the Sun is the zonal radiation balance of the earth's surface. Uneven heat input affects the location of air masses, moisture circulation and atmospheric circulation.
Zoning is expressed not only in the average annual amount of heat and moisture, but also in intra-annual changes. Climatic zoning is reflected in the runoff and hydrological regime, the formation of a weathering crust, and waterlogging. It has a great influence on the organic world, specific landforms. Homogeneous composition and high air mobility smooth out zonal differences with height.
In each hemisphere, 7 circulation zones are distinguished.
see also
Literature
- Milkov F. N., Gvozdetsky N. A. Physical geography of the USSR. Part 1. - M .: Higher School, 1986.
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See what "Latitude zoning" is in other dictionaries:
- (physico-geographical zonality), a change in natural conditions from the poles to the equator, due to latitudinal differences in the flow of solar radiation to the Earth's surface. Max. energy is received by a surface perpendicular to the sun's rays ... Geographic Encyclopedia
Geographic, regularity of differentiation of the geographic (landscape) shell of the Earth, manifested in a consistent and definite change of geographical belts and zones (see. Physical geographical zones), due primarily to ...
geographic zoning- Latitudinal differentiation of the geographic envelope of the Earth, manifested in the successive change of geographical belts, zones and subzones, due to changes in the arrival of the radiant energy of the Sun in latitudes and uneven moistening. → Fig. 367, p. ... ... Geography Dictionary
Ocean, World Ocean (from the Greek Ōkeanós ≈ Ocean, a great river flowing around the Earth). I. General information═ O. ≈ a continuous water shell of the Earth, surrounding the continents and islands and having a common salt composition. Makes up the majority of... Great Soviet Encyclopedia
I Ocean in ancient times Greek mythology one of the gods of the titans (See Titans), who had power over the world stream, which, according to the Greeks, surrounded the earthly firmament; son of Uranus and Gaia (See Gaia). In the struggle of Zeus and other gods of the Olympians with ... ... Great Soviet Encyclopedia
General Features soil cover Variability in space and time of soil formation factors (climate, relief, parent rock, vegetation, etc.), and as a result different history soil development ... ... Great Soviet Encyclopedia
The territory of the USSR lies in 4 geographical zones: the Arctic, where the Arctic desert zone is located; subarctic with tundra and forest-tundra zones; temperate with zones of taiga, mixed and broad-leaved forests (they can also be considered ... ... Great Soviet Encyclopedia
Physical-geographical (natural) countries There are several schemes for the physical-geographical zoning of a country's territory. This article uses a scheme according to which the territory of the USSR (together with some adjacent regions ... Great Soviet Encyclopedia
- (natural) There are several schemes of physico-geographical zoning (See Physico-geographical zoning) of the country's territory. This article uses a scheme according to which the territory of the USSR (together with some ... ... Great Soviet Encyclopedia
Paleogene system (period), Paleogene (from paleo ... and Greek genos birth, age), the oldest system of the Cenozoic group, corresponding to the first period of the Cenozoic era geological history Earth following the Cretaceous and preceding ... ... Great Soviet Encyclopedia
Latitudinal (geographical, landscape) zonality means a regular change in various processes, phenomena, individual geographical components and their combinations (systems, complexes) from the equator to the poles. Zonality in its elementary form was known even to the scientists of Ancient Greece, but the first steps in the scientific development of the theory of world zonality are associated with the name of A. Humboldt, who at the beginning of the 19th century. substantiated the concept of climatic and phytogeographic zones of the Earth. At the very end of the XIX century. V. V. Dokuchaev elevated latitudinal (horizontal in his terminology) zonality to the rank of world law.
For the existence of latitudinal zonality, two conditions are sufficient - the presence of a flux of solar radiation and the sphericity of the Earth. Theoretically, the flow of this flow to the earth's surface decreases from the equator to the poles in proportion to the cosine of latitude (Fig. 3). However, the actual amount of insolation reaching the earth's surface is also influenced by some other factors that are also of an astronomical nature, including the distance from the Earth to the Sun. With distance from the Sun, the flow of its rays becomes weaker, and at a sufficiently distant distance, the difference between polar and equatorial latitudes loses its significance; Thus, on the surface of the planet Pluto, the calculated temperature is close to -230 °C. When you get too close to the Sun, on the contrary, it turns out to be too hot in all parts of the planet. In both extreme cases, the existence of water in the liquid phase, life, is impossible. The Earth, therefore, is most "successfully" located in relation to the Sun.
The inclination of the earth's axis to the plane of the ecliptic (at an angle of about 66.5°) determines the uneven supply of solar radiation by season, which greatly complicates the zonal distribution
heat and exacerbates zonal contrasts. If the earth's axis were perpendicular to the plane of the ecliptic, then each parallel would receive almost the same amount of solar heat throughout the year, and there would be practically no seasonal change of phenomena on Earth. The daily rotation of the Earth, which causes the deviation of moving bodies, including air masses, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, introduces additional complications into the zoning scheme.
The mass of the Earth also affects the nature of zoning, although indirectly: it allows the planet (in contrast, for example, from "light-
171 Koi of the Moon) to keep the atmosphere, which serves as an important factor in the transformation and redistribution of solar energy.
With a homogeneous material composition and the absence of irregularities, the amount of solar radiation on the earth's surface would change strictly along latitude and would be the same on the same parallel, despite the complicating influence of the listed astronomical factors. But in the complex and heterogeneous environment of the epigeosphere, the solar radiation flux is redistributed and undergoes various transformations, which leads to a violation of its mathematically correct zoning.
Since solar energy is practically the only source of physical, chemical and biological processes that underlie the functioning of geographical components, these components must inevitably manifest latitudinal zonality. However, these manifestations are far from unambiguous, and the geographical mechanism of zonality turns out to be quite complex.
Already passing through the thickness of the atmosphere, the sun's rays are partially reflected and also absorbed by clouds. Because of this, the maximum radiation reaching the earth's surface is observed not at the equator, but in the belts of both hemispheres between the 20th and 30th parallels, where the atmosphere is most transparent to sunlight (Fig. 3). Over the land, the contrasts of atmospheric transparency are more significant than over the Ocean, which is reflected in the figure of the corresponding curves. The curves of the latitudinal distribution of the radiation balance are somewhat smoother, but it is clearly seen that the ocean surface is characterized by higher numbers than the land. The most important consequences of the latitudinal-zonal distribution of solar energy include the zonality of air masses, atmospheric circulation and moisture circulation. Under the influence of uneven heating, as well as evaporation from the underlying surface, four main zonal types of air masses are formed: equatorial (warm and humid), tropical (warm and dry), boreal, or masses of temperate latitudes (cool and humid), and arctic, and in Southern Hemisphere Antarctic (cold and relatively dry).
The difference in the density of air masses causes violations of thermodynamic equilibrium in the troposphere and mechanical movement (circulation) of air masses. Theoretically (without taking into account the influence of the Earth's rotation around its axis), air flows from heated equatorial latitudes should have risen up and spread to the poles, and from there cold and heavier air would have returned in the surface layer to the equator. But the deflecting effect of the planet's rotation (the Coriolis force) introduces significant amendments into this scheme. As a result, several circulation zones or belts are formed in the troposphere. For the equator
The al zone is characterized by low atmospheric pressure, calms, ascending air currents, for tropical ones - high pressure, winds with an eastern component (trade winds), for moderate ones - low pressure, westerly winds, for polar - low pressure, winds with an eastern component. In summer (for the corresponding hemisphere), the entire system of atmospheric circulation shifts to "its own" pole, and in winter - to the equator. Therefore, in each hemisphere, three transitional belts are formed - subequatorial, subtropical and subarctic (subantarctic), in which the types of air masses change seasonally. Due to atmospheric circulation, zonal temperature differences on the earth's surface are somewhat smoothed out, however, in the Northern Hemisphere, where the land area is much larger than in the Southern, the maximum heat supply is shifted to the north, up to about 10 - 20 ° N. sh. Since ancient times, it has been customary to distinguish five thermal zones on Earth: two cold and temperate and one hot. However, such a division is purely arbitrary, it is extremely schematic and its geographical significance is small. The continual nature of the change in air temperature near the earth's surface makes it difficult to distinguish between thermal zones. Nevertheless, using the latitudinal-zonal change of the main types of landscapes as a complex indicator, we can propose the following series of thermal zones that replace each other from the poles to the equator:
1) polar (arctic and antarctic);
2) subpolar (subarctic and subantarctic);
3) boreal (cold-temperate);
4) subboreal (warm-temperate);
5) pre-subtropical;
6) subtropical;
7) tropical;
8) subequatorial;
9) equatorial.
The zoning of moisture circulation and humidification is closely related to the zonality of atmospheric circulation. A peculiar rhythm is observed in the distribution of precipitation by latitude: two maxima (the main one at the equator and a secondary one in boreal latitudes) and two minima (in tropical and polar latitudes) (Fig. 4). The amount of precipitation, as is known, does not yet determine the conditions of moistening and moisture supply of landscapes. To do this, it is necessary to correlate the amount of annual precipitation with the amount that is necessary for the optimal functioning of the natural complex. The best integral indicator of the need for moisture is the value of evaporation, i.e., the limiting evaporation theoretically possible under given climatic (and, above all, temperature)
nyh) conditions. G. N. Vysotsky was the first to use this ratio in 1905 to characterize the natural zones of European Russia. Subsequently, N. N. Ivanov, independently of G. N. Vysotsky, introduced an indicator into science, which became known as moisture factor Vysotsky - Ivanov:
K=g/E,
where G- annual amount of precipitation; E- annual volatility 1 .
1 Dryness index is also used for comparative characteristics of atmospheric humidification rflr, proposed by M.I.Budyko and A.A. Grigoriev: where R- annual radiation balance; L- latent heat of evaporation; G is the annual amount of precipitation. In its physical meaning, this index is close to the inverse To Vysotsky-Ivanov. However, its use gives less accurate results.
On fig. Figure 4 shows that the latitudinal changes in precipitation and evaporation do not coincide and, to a large extent, even have an opposite character. As a result, on the latitude curve To in each hemisphere (for land) there are two critical points, where To passes through 1. Value TO- 1 corresponds to the optimum atmospheric humidification; at K> 1 moisture becomes excessive, and when To< 1 - insufficient. Thus, on the land surface in the very general view one can distinguish an equatorial belt of excessive moisture, two belts of insufficient moisture located symmetrically on both sides of the equator in low and middle latitudes, and two belts of excessive moisture in high latitudes (see Fig. 4). Of course, this is a highly generalized, averaged picture, which, as we shall see later, does not reflect gradual transitions between belts and significant longitudinal differences within them.
The intensity of many physical-geographical processes depends on the ratio of heat supply and moisture. However, it is easy to see that the latitudinal-zonal changes in temperature conditions and moisture have a different direction. If the reserves of solar heat in general increase from the poles to the equator (although the maximum is somewhat shifted to tropical latitudes), then the humidification curve has a pronounced undulating character. Without touching for the time being on the methods of quantitative assessment of the ratio of heat supply and moisture, we outline the most general patterns of changes in this ratio with respect to latitude. From the poles to approximately the 50th parallel, an increase in heat supply occurs under conditions of a constant excess of moisture. Further, with approaching the equator, an increase in heat reserves is accompanied by a progressive increase in dryness, which leads to frequent changes in landscape zones, the greatest diversity and contrast of landscapes. And only in a relatively narrow band on both sides of the equator is a combination of large heat reserves with abundant moisture observed.
To assess the impact of climate on the zonality of other components of the landscape and the natural complex as a whole, it is important to take into account not only the average annual values of heat and moisture supply indicators, but also their regime, i.e. intra-annual changes. So, for temperate latitudes, seasonal contrast of thermal conditions is characteristic with a relatively uniform intra-annual distribution of precipitation; in the subequatorial zone, with small seasonal differences in temperature conditions, the contrast between dry and wet seasons is sharply expressed, etc.
Climatic zoning is reflected in all other geographical phenomena - in the processes of runoff and the hydrological regime, in the processes of swamping and the formation of soil
175 waters, the formation of the weathering crust and soils, in the migration of chemical elements, as well as in the organic world. Zoning is also clearly manifested in the surface layer of the World Ocean. A particularly striking, to a certain extent integral expression geographic zoning found in vegetation and soils.
Separately, it should be said about the zonality of the relief and the geological foundation of the landscape. In the literature, one can come across statements that these components do not obey the law of zoning, i.e. azonal. First of all, it should be noted that it is wrong to divide the geographical components into zonal and azonal, because, as we will see, each of them manifests the influence of both zonal and azonal regularities. The relief of the earth's surface is formed under the influence of the so-called endogenous and exogenous factors. The former include tectonic movements and volcanism, which are of an azonal nature and create morphostructural features of the relief. Exogenous factors are associated with the direct or indirect participation of solar energy and atmospheric moisture, and the sculptural forms of relief created by them are distributed zonally on the Earth. It is enough to recall the specific forms of the glacial relief of the Arctic and Antarctic, thermokarst depressions and heaving mounds of the Subarctic, ravines, gullies and subsidence depressions of the steppe zone, eolian forms and drainless solonchak depressions of the desert, etc. In forest landscapes, a powerful vegetation cover restrains the development of erosion and determines the predominance of a “soft” poorly dissected relief. The intensity of exogenous geomorphological processes, such as erosion, deflation, karst formation, depends significantly on latitudinal-zonal conditions.
In the building earth's crust azonal and zonal features are also combined. If the igneous rocks are unquestionably azonal in origin, then the sedimentary stratum is formed under the direct influence of climate, the vital activity of organisms, and soil formation, and cannot but bear the stamp of zonality.
Throughout geological history, sedimentation (lithogenesis) proceeded differently in different zones. In the Arctic and Antarctic, for example, unsorted clastic material (moraine) accumulated, in the taiga - peat, in deserts - clastic rocks and salts. For each specific geological epoch, it is possible to reconstruct the picture of the zones of that time, and each zone will have its own types of sedimentary rocks. However, over the course of geological history, the system of landscape zones has undergone repeated changes. Thus, for modern geological map superimposed results of lithogenesis
176 of all geological periods when the zones were not at all the same as they are now. Hence the external diversity of this map and the absence of visible geographical patterns.
It follows from what has been said that zoning cannot be regarded as some simple imprint of the present-day climate in the earth's space. Essentially, landscape areas are spatio-temporal formations, they have their own age, their own history and are changeable both in time and space. The modern landscape structure of the epigeosphere developed mainly in the Cenozoic. The equatorial zone is distinguished by the greatest antiquity, as the distance to the poles increases, the zonality experiences increasing variability, and the age of modern zones decreases.
The last significant restructuring of the world system of zonality, which captured mainly high and temperate latitudes, is associated with continental glaciations of the Quaternary period. The oscillatory displacements of the zones continue here in the post-glacial period as well. In particular, over the past millennia there was at least one period when the taiga zone in some places advanced to the northern margin of Eurasia. The tundra zone within its current boundaries emerged only after the subsequent retreat of the taiga to the south. The reasons for such changes in the position of the zones are associated with rhythms of cosmic origin.
The action of the law of zoning is most fully manifested in the relatively thin contact layer of the epigeosphere, i.e. in the landscape area. With distance from the surface of the land and ocean to the outer boundaries of the epigeosphere, the influence of zoning weakens, but does not completely disappear. Indirect manifestations of zoning are observed at great depths in the lithosphere, practically in the entire stratisphere, i.e., thicker than sedimentary rocks, the relationship of which with zoning has already been discussed. Zonal differences in the properties of artesian waters, their temperature, salinity, chemical composition can be traced to a depth of 1000 m or more; the fresh groundwater horizon in zones of excessive and sufficient moisture can reach a thickness of 200-300 and even 500 m, while in arid zones the thickness of this horizon is insignificant or it is completely absent. On the ocean floor, zoning indirectly manifests itself in the nature of bottom silts, which are predominantly of organic origin. It can be assumed that the zoning law applies to the entire troposphere, since its most important properties are formed under the influence of the subaerial surface of the continents and the World Ocean.
In Russian geography, for a long time, the importance of the law of zoning for human life and social production was underestimated. The judgments of V.V. Dokuchaev on this topic are regarded as
177 were exaggerated and a manifestation of geographical determinism. Territorial differentiation of population and economy has its own patterns, which cannot be fully reduced to action. natural factors. However, to deny the influence of the latter on the processes taking place in human society would be a gross methodological mistake, fraught with serious socio-economic consequences, as we are convinced by all historical experience and modern reality.
Various aspects of the manifestation of the law of latitudinal zonality in the sphere of socio-economic phenomena are discussed in more detail in Chap. 4.
The law of zoning finds its most complete, complex expression in the zonal landscape structure of the Earth, i.e. in the existence of the system landscape zones. The system of landscape zones should not be imagined as a series of geometrically regular continuous stripes. Even V. V. Dokuchaev did not conceive of the zone as an ideal form of a belt, strictly delimited by parallels. He emphasized that nature is not mathematics, and zoning is only a scheme or law. With further study of landscape zones, it was found that some of them are broken, some zones (for example, the zone of deciduous forests) are developed only in the peripheral parts of the continents, others (deserts, steppes), on the contrary, gravitate towards inland regions; the boundaries of the zones to a greater or lesser extent deviate from the parallels and in some places acquire a direction close to the meridional; in the mountains, latitudinal zones seem to disappear and are replaced by altitudinal zones. Similar facts gave rise to in the 30s. 20th century some geographers argue that latitudinal zoning is not at all a universal law, but only a special case characteristic of large plains, and that its scientific and practical significance is exaggerated.
In reality, various kinds of violations of zoning do not refute its universal significance, but only indicate that it manifests itself differently in different conditions. Every natural law operates differently in different conditions. This also applies to such simple physical constants as the freezing point of water or the magnitude of the acceleration of gravity: they are not violated only under the conditions of a laboratory experiment. In the epigeosphere, many natural laws operate simultaneously. The facts, which at first glance do not fit into the theoretical model of zonality with its strictly latitudinal continuous zones, indicate that zonality is not the only geographical regularity, and it is impossible to explain the whole complex nature of territorial physical and geographical differentiation by it alone.
178 pressure peaks. In the temperate latitudes of Eurasia, the differences in the average January air temperatures on the western periphery of the continent and in its inner extreme continental part exceed 40 °C. In summer, it is warmer in the depths of the continents than on the periphery, but the differences are not so great. A generalized idea of the degree of oceanic influence on the temperature regime of the continents is provided by indicators of the continentality of the climate. Exist various ways calculation of such indicators based on taking into account the annual amplitude of average monthly temperatures. The most successful indicator, taking into account not only the annual amplitude of air temperatures, but also the daily one, as well as the lack of relative humidity in the driest month and the latitude of the point, was proposed by N.N. Ivanov in 1959. Taking the average planetary significance indicator for 100%, the scientist broke down the whole series of values obtained by him for different points the globe, per ten belts of continentality (numbers in parentheses are given as a percentage):
1) extremely oceanic (less than 48);
2) oceanic (48 - 56);
3) temperate oceanic (57 - 68);
4) marine (69 - 82);
5) weak marine (83-100);
6) weak continental (100-121);
7) temperate continental (122-146);
8) continental (147-177);
9) sharply continental (178 - 214);
10) extremely continental (more than 214).
On the scheme of the generalized continent (Fig. 5), the climate continentality belts are located in the form of irregularly shaped concentric bands around the extremely continental cores in each hemisphere. It is easy to see that almost at all latitudes, continentality varies within wide limits.
About 36% of atmospheric precipitation falling on the land surface is of oceanic origin. As they move inland, sea air masses lose moisture, leaving most of it on the periphery of the continents, especially on the slopes of mountain ranges facing the Ocean. The greatest longitudinal contrast in the amount of precipitation is observed in tropical and subtropical latitudes: abundant monsoon rains on the eastern periphery of the continents and extreme aridity in the central, and partly in the western regions, exposed to the continental trade winds. This contrast is exacerbated by the fact that evaporation increases sharply in the same direction. As a result, on the Pacific periphery of the tropics of Eurasia, the moisture coefficient reaches 2.0 - 3.0, while in most of the space of the tropical zone it does not exceed 0.05,
The landscape-geographic consequences of the continental-ocean circulation of air masses are extremely diverse. In addition to heat and moisture, various salts come from the Ocean with air currents; this process, called by G.N. Vysotsky impulverization, is the most important reason for the salinization of many arid regions. It has long been noted that as you move away from the ocean coasts into the depths of the continents, there is a regular change in plant communities, animal populations, soil types. In 1921, VL Komarov called this regularity meridional zoning; he believed that three meridional zones should be distinguished on each continent: one inland and two oceanic. In 1946, this idea was concretized by the Leningrad geographer A. I. Yaunputnin. In his
181 physical-geographical zoning of the Earth, he divided all the continents into three longitudinal sectors- western, eastern and central, and for the first time noted that each sector is distinguished by its own set of latitudinal zones. However, the predecessor of A.I. Yaunputnin should be considered the English geographer A.J. Herbertson, who as early as 1905 divided the land into natural belts and in each of them identified three longitude segments - western, eastern and central.
With a subsequent, deeper study of the pattern, which has become customary to call the longitudinal sector, or simply sector, it turned out that the three-term sectoral division of the entire land is too schematic and does not reflect the complexity of this phenomenon. The sectoral structure of the continents is clearly asymmetric and is not the same in different latitudinal zones. Thus, in tropical latitudes, as already noted, a two-term structure is clearly outlined, in which the continental sector dominates, while the western sector is reduced. In the polar latitudes, sectoral physical and geographical differences are weakly manifested due to the dominance of fairly homogeneous air masses, low temperatures, and excessive moisture. In the boreal zone of Eurasia, where the land has the greatest (almost 200°) longitude extension, on the contrary, not only are all three sectors well expressed, but it also becomes necessary to establish additional, transitional steps between them.
The first detailed scheme of sectoral division of the land, implemented on the maps of the Physical and Geographical Atlas of the World (1964), was developed by E. N. Lukashova. There are six physical-geographical (landscape) sectors in this scheme. The use of quantitative indicators as criteria for sectoral differentiation of quantitative indicators - moisture coefficients and continental ™, and as a complex indicator - the boundaries of the distribution of zonal landscape types made it possible to detail and clarify the scheme of E. N. Lukashova.
Here we come to the essential question of the relationship between zoning and sectoring. But first it is necessary to pay attention to a certain duality in the use of terms zone and sector. In a broad sense, these terms are used as collective, essentially typological concepts. So, when they say “desert zone” or “steppe zone” (in the singular), they often mean the whole set of territorially separated areas with the same type of zonal landscapes, which are scattered in different hemispheres, on different continents and in different sectors of the latter. Thus, in such cases, the zone is not thought of as a single integral territorial block or region, i.e. cannot be considered as an object of zoning. But at the same time, the same ter-
182 mines can refer to specific, integral territorially separate divisions that correspond to the idea of the region, for example Desert zone of Central Asia, Steppe zone of Western Siberia. In this case, they deal with objects (taxa) of zoning. In the same way, we have the right to speak, for example, of the “western oceanic sector” in the broadest sense of the word as a global phenomenon that unites a number of specific territorial areas on various continents - in the Atlantic part of Western Europe and the Atlantic part of the Sahara, along the Pacific slopes of the Rocky mountains, etc. Each such piece of land is an independent region, but all of them are analogues and are also called sectors, but understood in a narrower sense of the word.
The zone and sector in the broad sense of the word, which has a clearly typological connotation, should be interpreted as a common noun and, accordingly, their names should be written with a lowercase letter, while the same terms in the narrow (i.e., regional) sense and included in their own geographical name, - capitalized. Options are possible, for example: Western European Atlantic sector instead of Western European Atlantic sector; Eurasian steppe zone instead of Eurasian steppe zone (or Eurasian steppe zone).
There are complex relationships between zoning and sectoring. Sector differentiation largely determines the specific manifestations of the law of zoning. The longitude sectors (in the broadest sense) are, as a rule, extended across the strike of the latitudinal zones. When moving from one sector to another, each landscape zone undergoes a more or less significant transformation, and for some zones, the boundaries of the sectors turn out to be completely insurmountable barriers, so that their distribution is limited to strictly defined sectors. For example, the Mediterranean zone is confined to the western near-oceanic sector, and the subtropical humid-forest - to the eastern near-oceanic (Table 2 and Fig. b) 1 . The reasons for such apparent anomalies should be sought in the zonal-sector laws.
1 In fig. 6 (as in Fig. 5) all the continents are brought together in strict accordance with the distribution of land in latitude, observing a linear scale along all parallels and the axial meridian, i.e. in the Sanson equal area projection. In this way, the actual area ratio of all contours is transmitted. A similar, widely known and included in the textbook scheme of E. N. Lukashova and A. M. Ryabchikov was built without observing the scale and therefore distorts the proportions between the latitudinal and longitude extent of the conditional land mass and the areal relationships between individual contours. The essence of the proposed model is more precisely expressed by the term generalized continent instead of the commonly used perfect continent.
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numbers of distribution of solar energy and especially atmospheric humidification.
The main criteria for diagnosing landscape zones are objective indicators of heat supply and moisture. It has been experimentally established that among the many possible indicators for our purpose, the most appropriate
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rows of landscape zones-analogues in terms of heat supply". I - polar; II - subpolar; III - boreal; IV - subboreal; V - pre-subtropical; VI - subtropical; VII - tropical and subequatorial; VIII - equatorial; rows of landscape zones-analogues in terms of moisture: A - extraarid; B - arid; B - semiarid; G - semi-humid; D - humid; 1 - 28 - landscape zones (explanations in Table 2); T- the sum of temperatures for the period with average daily air temperatures above 10 °C; To- moisture coefficient. Scales - logarithmic
It should be noted that each such series of analogue zones fits into a certain range of values of the accepted heat supply indicator. So, the zones of the subboreal series lie in the range of the sum of temperatures 2200-4000 "C, subtropical - 5000 - 8000" C. Within the accepted scale, less clear thermal differences are observed between the zones of the tropical, subequatorial, and equatorial belts, but this is quite natural, since in this case, the determining factor of zonal differentiation is not heat supply, but humidification 1 .
If the series of analogous zones in terms of heat supply generally coincide with latitudinal belts, then the humidification series are of a more complex nature, containing two components - zonal and sectoral, and there is no unidirectionality in their territorial change. Differences in atmospheric humidification
1 Due to this circumstance, and also due to the lack of reliable data in Table. 2 and in fig. 7 and 8 tropical and sub equatorial belt but combined and related zones-analogues are not delimited.
187 are caught both by zonal factors during the transition from one latitudinal belt to another, and by sectoral factors, i.e., by longitudinal advection of moisture. Therefore, the formation of zones-analogues in terms of moisture in some cases is associated mainly with zoning (in particular, taiga and equatorial forest in the humid series), in others - with sector (for example, subtropical humid forest in the same series), and in others - with a coinciding effect both patterns. The latter case includes zones of subequatorial variable-humid forests and forest avannas.
Latitudinal (geographical, landscape) zonality means a regular change in various processes, phenomena, individual geographical components and their combinations (systems, complexes) from the equator to the poles. Zonality in its elementary form was known even to the scientists of ancient Greece, but the first steps in the scientific development of the theory of world zonality are associated with the name of A. Humboldt, who at the beginning of the 19th century. substantiated the concept of climatic and phytogeographic zones of the Earth. At the very end of the XIX century. V.V. Dokuchaev elevated latitudinal (horizontal in his terminology) zonality to the rank of world law.For the existence of latitudinal zonality, two conditions are sufficient - the presence of a flux of solar radiation and the sphericity of the Earth. Theoretically, the flow of this flow to the earth's surface decreases from the equator to the poles in proportion to the cosine of latitude (Fig. 1). However, the actual amount of insolation reaching the earth's surface is also influenced by some other factors that are also of an astronomical nature, including the distance from the Earth to the Sun. As we move away from the Sun, the flow of its rays becomes weaker, and at a sufficiently distant distance, the difference between polar and equatorial latitudes loses its significance; Thus, on the surface of the planet Pluto, the calculated temperature is close to -230°C. When you get too close to the Sun, on the contrary, it turns out to be too hot in all parts of the planet. In both extreme cases, the existence of water in the liquid phase, life, is impossible. The Earth, therefore, is most "successfully" located in relation to the Sun.
The inclination of the earth's axis to the plane of the ecliptic (at an angle of about 66.5°) determines the uneven supply of solar radiation by season, which significantly complicates the zonal distribution of heat and exacerbates zonal contrasts. If the earth's axis were perpendicular to the plane of the ecliptic, then each parallel would receive almost the same amount of solar heat throughout the year, and there would be practically no seasonal change of phenomena on Earth. The daily rotation of the Earth, which causes the deviation of moving bodies, including air masses, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, introduces additional complications into the zoning scheme.
Rice. 1. Distribution of solar radiation by latitude:
Rc - radiation at the upper boundary of the atmosphere; total radiation: 
- on the surface of the land, 
- on the surface of the World Ocean; 
- average for the surface of the globe; radiation balance: Rc - on the surface of the land, Ro - on the surface of the ocean, R3 - on the surface of the globe (average value)
The mass of the Earth also affects the nature of zoning, albeit indirectly: it allows the planet (unlike, for example, the “light” Moon) to retain an atmosphere, which serves as an important factor in the transformation and redistribution of solar energy.
With a homogeneous material composition and the absence of irregularities, the amount of solar radiation on the earth's surface would change strictly along latitude and would be the same on the same parallel, despite the complicating influence of the listed astronomical factors. But in the complex and heterogeneous environment of the epigeosphere, the solar radiation flux is redistributed and undergoes various transformations, which leads to a violation of its mathematically correct zoning.
Since solar energy is practically the only source of physical, chemical and biological processes underlying the functioning of geographical components, these components must inevitably manifest latitudinal zonality. However, these manifestations are far from unambiguous, and the geographical mechanism of zonality turns out to be quite complex.
Already passing through the thickness of the atmosphere, the sun's rays are partially reflected and also absorbed by clouds. Because of this, the maximum radiation reaching the earth's surface is observed not at the equator, but in the belts of both hemispheres between the 20th and 30th parallels, where the atmosphere is most transparent to sunlight (Fig. 1). Over land, the contrasts in atmospheric transparency are more significant than over the ocean, which is reflected in the figure of the corresponding curves. The curves of the latitudinal distribution of the radiation balance are somewhat smoother, but it is clearly seen that the ocean surface is characterized by higher numbers than the land. The most important consequences of the latitudinal-zonal distribution of solar energy include the zonality of air masses, atmospheric circulation and moisture circulation. Under the influence of uneven heating, as well as evaporation from the underlying surface, four main zonal types of air masses are formed: equatorial (warm and humid), tropical (warm and dry), boreal, or masses of temperate latitudes (cool and humid), and arctic, and in Southern Hemisphere Antarctic (cold and relatively dry).
The difference in the density of air masses causes violations of thermodynamic equilibrium in the troposphere and mechanical movement (circulation) of air masses. Theoretically (without taking into account the influence of the Earth's rotation around its axis), air flows from heated equatorial latitudes should have risen up and spread to the poles, and from there cold and heavier air would have returned in the surface layer to the equator. But the deflecting effect of the planet's rotation (the Coriolis force) introduces significant amendments into this scheme. As a result, several circulation zones or belts are formed in the troposphere. The equatorial belt is characterized by low atmospheric pressure, calms, ascending air currents, for tropical - high pressure, winds with an easterly component (trade winds), for moderate ones - low pressure, westerly winds, for polar ones - low pressure, winds with an easterly component. In summer (for the corresponding hemisphere), the entire atmospheric circulation system shifts to its “own” pole, and in winter, to the equator. Therefore, three transitional belts are formed in each hemisphere - subequatorial, subtropical and subarctic (subantarctic), in which the types of air masses change seasonally. Due to atmospheric circulation, zonal temperature differences on the earth's surface are somewhat smoothed out, however, in the Northern Hemisphere, where the land area is much larger than in the Southern Hemisphere, the maximum heat supply is shifted to the north, to about 10-20 ° N.L. Since ancient times, it has been customary to distinguish five thermal zones on Earth: two cold and temperate and one hot. However, such a division is purely arbitrary, it is extremely schematic and its geographical significance is small. The continual nature of the change in air temperature near the earth's surface makes it difficult to distinguish between thermal zones. Nevertheless, using the latitudinal-zonal change of the main types of landscapes as a complex indicator, we can propose the following series of thermal zones that replace each other from the poles to the equator:
1) polar (arctic and antarctic);
2) subpolar (subarctic and subantarctic);
3) boreal (cold-temperate);
4) subboreal (warm-temperate);
5) pre-subtropical;
6) subtropical;
7) tropical;
8) subequatorial;
9) equatorial.
The zonality of moisture circulation and humidification is closely related to the zonality of atmospheric circulation. In the distribution of precipitation by latitude, a peculiar rhythm is observed: two maxima (the main one at the equator and a secondary one in boreal latitudes) and two minima (in tropical and polar latitudes) (Fig. 2). The amount of precipitation, as is known, does not yet determine the conditions of moistening and moisture supply of landscapes. To do this, it is necessary to correlate the amount of annual precipitation with the amount that is necessary for the optimal functioning of the natural complex. The best integral indicator of the need for moisture is the value of evaporation, i.e. limiting evaporation, theoretically possible under given climatic (and, above all, temperature) conditions. G.N. Vysotsky was the first to use this ratio in 1905 to characterize the natural zones of European Russia. Subsequently, N.N. Ivanov, regardless of G.N. Vysotsky introduced an indicator into science, which became known as the Vysotsky-Ivanov moisture coefficient:
K \u003d r / E,
where r is the annual amount of precipitation; E - annual value of evaporation1.
Figure 2 shows that the latitudinal changes in precipitation and evaporation do not coincide and, to a large extent, even have the opposite character. As a result, on the latitude curve K in each hemisphere (for land), two critical points are distinguished, where K passes through 1. The value K = 1 corresponds to the optimum atmospheric humidification; at K > 1, moisture becomes excessive, and at K< 1 - недостаточным. Таким образом, на поверхности суши в самом общем виде можно выделить экваториальный пояс избыточного увлажнения, два симметрично расположенных по обе стороны от экватора пояса недостаточного увлажнения в низких и средних широтах и два пояса избыточного увлажнения в высоких широтах (рис. 2). Разумеется, это сильно генерализованная, осреднённая картина, не отражающая, как мы увидим в дальнейшем, постепенных переходов между поясами и существенных долготных различий внутри них.
Rice. 2. Distribution of precipitation, evaporation
And the coefficient of moisture in latitude on the land surface:
1 - average annual precipitation; 2 - average annual evaporation;
3 - excess of precipitation over evaporation; 4 - excess
Evaporation over precipitation; 5 - moisture coefficient
The intensity of many physical and geographical processes depends on the ratio of heat supply and moisture. However, it is easy to see that the latitudinal-zonal changes in temperature conditions and moisture have a different direction. If the reserves of solar heat generally increase from the poles to the equator (although the maximum is somewhat shifted to tropical latitudes), then the humidification curve has a pronounced undulating character. Without touching for the time being on the methods of quantitative assessment of the ratio of heat supply and moisture, we outline the most general patterns of changes in this ratio with respect to latitude. From the poles to approximately the 50th parallel, an increase in heat supply occurs under conditions of a constant excess of moisture. Further, with approaching the equator, an increase in heat reserves is accompanied by a progressive increase in dryness, which leads to frequent changes in landscape zones, the greatest diversity and contrast of landscapes. And only in a relatively narrow band on both sides of the equator is a combination of large heat reserves with abundant moisture observed.
To assess the impact of climate on the zonality of other components of the landscape and the natural complex as a whole, it is important to take into account not only the average annual values of heat and moisture supply indicators, but also their regime, i.e. intra-annual changes. Thus, temperate latitudes are characterized by seasonal contrast of thermal conditions with a relatively uniform intra-annual distribution of precipitation; in the subequatorial zone, with small seasonal differences in temperature conditions, the contrast between dry and wet seasons is sharply expressed, etc.
Climatic zoning is reflected in all other geographical phenomena - in the processes of runoff and the hydrological regime, in the processes of swamping and the formation of groundwater, the formation of a weathering crust and soils, in the migration of chemical elements, as well as in the organic world. Zoning is clearly manifested in the surface layer of the World Ocean. Geographic zonality finds a particularly striking, to a certain extent integral expression in the vegetation cover and soils.
Separately, it should be said about the zonality of the relief and the geological foundation of the landscape. In the literature, one can come across statements that these components do not obey the law of zoning, i.e. azonal. First of all, it should be noted that it is wrong to divide the geographical components into zonal and azonal, because, as we will see, each of them manifests the influence of both zonal and azonal regularities. The relief of the earth's surface is formed under the influence of the so-called endogenous and exogenous factors. The former include tectonic movements and volcanism, which are of an azonal nature and create morphostructural features of the relief. Exogenous factors are associated with the direct or indirect participation of solar energy and atmospheric moisture, and the sculptural forms of relief created by them are distributed zonally on the Earth. It is enough to recall the specific forms of the glacial relief of the Arctic and Antarctic, thermokarst depressions and heaving mounds of the Subarctic, ravines, gullies and subsidence depressions of the steppe zone, eolian forms and drainless solonchak depressions of the desert, etc. In forest landscapes, a powerful vegetation cover restrains the development of erosion and determines the predominance of a “soft” weakly dissected relief. The intensity of exogenous geomorphological processes, such as erosion, deflation, karst formation, depends significantly on latitudinal-zonal conditions.
The structure of the earth's crust also combines azonal and zonal features. If the igneous rocks are unquestionably azonal in origin, then the sedimentary stratum is formed under the direct influence of climate, the vital activity of organisms, and soil formation, and cannot but bear the stamp of zonality.
Throughout geological history, sedimentation (lithogenesis) proceeded differently in different zones. In the Arctic and Antarctic, for example, unsorted clastic material (moraine) accumulated, in the taiga - peat, in deserts - clastic rocks and salts. For each specific geological epoch, it is possible to reconstruct the picture of the zones of that time, and each zone will have its own types of sedimentary rocks. However, over the course of geological history, the system of landscape zones has undergone repeated changes. Thus, the results of lithogenesis of all geological periods, when the zones were completely different from what they are now, were superimposed on the modern geological map. Hence the external diversity of this map and the absence of visible geographical patterns.
It follows from what has been said that zoning cannot be regarded as some simple imprint of the present-day climate in the earth's space. Essentially, landscape zones are spatio-temporal formations, they have their own age, their own history and are changeable both in time and space. The modern landscape structure of the epigeosphere developed mainly in the Cenozoic. The equatorial zone is distinguished by the greatest antiquity, as the distance to the poles, the zoning experiences more and more variability, and the age of modern zones decreases.
The last significant restructuring of the world system of zoning, which captured mainly high and temperate latitudes, is associated with continental glaciations of the Quaternary period. The oscillatory displacements of the zones continue here in the post-glacial period as well. In particular, over the past millennia there was at least one period when the taiga zone in some places advanced to the northern edge of Eurasia. The tundra zone within its current boundaries arose only after the subsequent retreat of the taiga to the south. The reasons for such changes in the position of the zones are associated with rhythms of cosmic origin.
The action of the law of zoning is most fully manifested in the relatively thin contact layer of the epigeosphere, i.e. in the landscape area. As the distance from the surface of the land and ocean to the outer boundaries of the epigeosphere, the influence of zoning weakens, but does not completely disappear. Indirect manifestations of zoning are observed at great depths in the lithosphere, practically in the entire stratosphere; thicker than sedimentary rocks, the relationship of which with zonality has already been mentioned. Zonal differences in the properties of artesian waters, their temperature, salinity, chemical composition can be traced to a depth of 1000 m or more; the horizon of fresh groundwater in zones of excessive and sufficient moisture can reach a thickness of 200-300 and even 500 m, while in arid zones the thickness of this horizon is insignificant or it is completely absent. On the ocean floor, zoning indirectly manifests itself in the nature of bottom silts, which are predominantly of organic origin. It can be assumed that the zoning law applies to the entire troposphere, since its most important properties are formed under the influence of the subaerial surface of the continents and the World Ocean.
In Russian geography, for a long time, the importance of the law of zoning for human life and social production was underestimated. The judgments of V.V. Dokuchaev on this topic were regarded as an exaggeration and a manifestation of geographical determinism. Territorial differentiation of population and economy has its own patterns, which cannot be completely reduced to the action of natural factors. However, to deny the influence of the latter on the processes taking place in human society would be a gross methodological mistake, fraught with serious socio-economic consequences, as we are convinced by all historical experience and modern reality.
The law of zoning finds its most complete, complex expression in the zonal landscape structure of the Earth, i.e. in the existence of a system of landscape zones. The system of landscape zones should not be imagined as a series of geometrically regular continuous stripes. More V.V. Dokuchaev did not conceive of the zone as an ideal form of a belt, strictly demarcated along the parallels. He emphasized that nature is not mathematics, and zoning is just a scheme or a law. With further study of landscape zones, it was found that some of them are broken, some zones (for example, the zone of broad-leaved forests) are developed only in the peripheral parts of the continents, others (deserts, steppes), on the contrary, gravitate towards inland regions; the boundaries of the zones to a greater or lesser extent deviate from the parallels and in some places acquire a direction close to the meridional; in the mountains, latitudinal zones seem to disappear and are replaced by altitudinal zones. Similar facts gave rise to in the 30s. 20th century some geographers to argue that latitudinal zoning is not at all a universal law, but only a special case characteristic of large plains, and that its scientific and practical value exaggerated.
In reality, various kinds of violations of zoning do not refute its universal significance, but only indicate that it manifests itself differently in different conditions. Every natural law operates differently in different conditions. This also applies to such simple physical constants as the freezing point of water or the magnitude of the acceleration of gravity. They are not violated only under the conditions of a laboratory experiment. In the epigeosphere, many natural laws operate simultaneously. Facts that at first glance do not fit into theoretical model zonality with its strictly latitudinal continuous zones indicate that zonality is not the only geographical regularity, and it is impossible to explain the whole complex nature of territorial physical and geographical differentiation by it alone.
Energy sources for natural processes
No planet solar system does not have the opportunity to "boast" of such an extraordinary variety of natural landscapes as the Earth. In general, the very presence of landscapes by default is an amazing fact. No one can give an exhaustive answer why heterogeneous natural components, under favorable conditions, are combined into a single inseparable system. But to try to explain exactly the reasons for such a motley landscape ensemble is quite a feasible task.
As is known, natural system The Earth lives and develops mainly due to two types of energy:
1. Solar (exogenous)
2. Intraterrestrial (endogenous)
These types of energy are the same in strength, but are useful in various aspects of the evolution of geographic space. So solar energy, interacting with the earth's surface, launches a chain of global natural mechanisms responsible for climate formation, which, in turn, affects soil-vegetative, hydrological and external geological processes. The intraterrestrial energy, acting on the entire thickness of the lithosphere, naturally affects its surface, causing us to perceive tectonic movements of the earth's crust and seismic and magmatic phenomena closely related to them. The end result of tectonic movements is the division of the earth's surface into morphostructures that determine (the distribution of land and sea) and major differences in the relief of land and the bottom of the World Ocean.
All processes and phenomena caused by the contact of solar radiation with the day surface are called zonal. They mainly cover the surface, penetrating to an insignificant depth (on the scale of the entire Earth). Opposite them azonal processes- this is the result of the impact on the earth's crust of energy flows formed as a result of the internal geological development (functioning) of the Earth. As already mentioned, these flows, having a deep origin, cover the entire tectonosphere with their influence and set it in motion, which is certainly transmitted to the earth's surface. The main intraterrestrial processes that provide energy food for azonation include the following:
Gravitational differentiation of terrestrial matter (when lighter elements rise up and heavier ones fall down). This explains the structure of the Earth: the core consists almost entirely of iron, and the atmosphere, the outer shell of the earth, is a physical mixture of gases;
Alternating change in the radius of the Earth;
Energy of interatomic bonds in minerals;
Radioactive decay of chemical elements (mainly thorium and uranium).
If every point on the earth's surface received the same amount of energy (both external and internal), then the natural environment would be homogeneous in zonal and azonal terms. But the figure of the Earth, its size, material composition and astronomical features exclude this possibility, and therefore the energy is distributed extremely unevenly over the surface. Some parts of the Earth receive more energy, others less. As a result, the entire surface is divided into more or less homogeneous areas. This homogeneity is internal, but the sections themselves differ in all respects. In the classical domestic science of the nature of the Earth, zonal homogeneous units of regional land zoning are called landscape zones; azonally homogeneous - landscape countries, and in general terms, the boundaries of countries coincide with the boundaries of morphostructures.
The real existence of such natural formations there is no doubt, but in natural conditions their spatial structure is, of course, much more complicated than in the modern scientific understanding.
In addition to the types of energy described above, the Earth is also influenced by other equally strong ones, but they do not play a fundamental role in the differentiation of the natural environment. Their significance lies in the regulation of natural mechanisms at the global level. They also introduce significant deviations in zonal and azonal processes, changing the direction of movement of air and water masses, causing a change in seasons, tides in the Ocean and even the lithosphere. That is, they make some amendments to the structure of matter-energy flows, establish the rhythm and cyclicity of all natural phenomena. These types of energy include the energy of the axial and orbital rotation of the Earth, gravitational interaction with other celestial bodies, mainly with the Moon and the Sun.
Z o n a lity
The surface of the planet Earth is characterized by two opposite qualities - zonality and azonality.
Zoning in physical geography is a set of interrelated phenomena on the surface of the Earth, caused by the interaction of solar radiation with the daytime surface and leading to the formation of landscape zones on land and belts on the surface and bottom of the World Ocean.
Zoning on land (terrestrial landscape sphere)
On land, zonality is expressed in the existence of landscape zones, internally homogeneous territories with a certain climatic regime, soil and vegetation cover, exogenous geological processes and hydrological features - the density of the hydrographic network (total watering of the territory), as well as the regime of water bodies and groundwater.
Landscape zones on land, as mentioned above, are formed under the direct influence of climate on the earth's surface. Of all the climatic elements (temperature, precipitation, pressure, humidity, cloudiness) in this section, we will be interested in only two - air temperature and precipitation (frontal, convective, orographic), that is, heat and precipitation, which are supplied to the landscape zone during the year.
Both the absolute amount of heat and moisture and their combination are important for the formation of a landscape zone.
The ideal combination is considered to be close to 1:1 (evapotranspiration is approximately equal to the amount of precipitation), when the thermal features (heat supply, evaporation) of the zone make it possible to evaporate all the precipitation that falls during the year. At the same time, they do not just evaporate without any benefit, but do a certain job in natural complexes, "revitalizing" them.
In general, the combination of heat and moisture is characterized by five options:
1. A little more precipitation falls than can evaporate - forests develop.
2. Precipitation falls exactly as much as it can evaporate (or a little less) - forest-steppes and natural savannas develop.
3. Much less precipitation falls than can evaporate - steppes develop.
4. Much less precipitation falls than can evaporate - deserts and semi-deserts develop.
5. Much more precipitation falls than can evaporate; in this case, the "excess" water, not being able to completely evaporate, flows into the recesses, and, if the geological features of the area allow, causes swamping. Bogs mainly develop in tundra and forest landscapes. Although wetlands can also be found in dry areas. This is already connected with the hydrogeological qualities of the area.
Thus, the combination of these climatic elements (heat and moisture) depends zone type(forest, forest-steppe, steppe, semi-desert, desert). From the absolute amount of precipitation and average annual temperatures, as well as temperatures of the coldest and warm month year depends on the specific nature of the zone(forest equatorial, forest temperate, tropical desert, temperate desert, etc.).
So, with all the variety of land landscape zones, they can be divided into five types:
1. Desert zones
2. Semi-desert zones
3. steppe zones(including tundra)
4. Forest-steppe zones
5. Forest zones
It is the combination of heat and moisture that determines zone type. Specific nature of the zone depends on which geographic zone it is located in. In total, there are seven belts on Earth:
1. Arctic belt
2. Antarctic belt
3. Temperate zone northern hemisphere
4. Temperate Southern Hemisphere
5. Subtropical belt of the Northern Hemisphere
6. Subtropical belt of the Southern Hemisphere
7. Tropical belt (including areas of subequatorial and equatorial climate)
In each belt are formed all types natural zones. It is by this criterion that the geographical zone is distinguished - by the full development of zoning.
Variants of zoning on land
The climate, on which the type and nature of the natural zone depends, is formed under the influence of three main factors:
1. Amounts of solar radiation
2. Circulation of air masses
3. The nature of the underlying surface (n For example, the Arctic and Antarctic territories are such largely due to their white surface, which reflects almost all the solar radiation that comes in a year)
Quantitative and qualitative characteristics of all three factors undergo significant changes in latitude, longitude and in the vertical direction. This causes a change in indicators and the main climatic elements (air temperature and precipitation). Following temperature and precipitation, natural areas, as well as their internal qualities, also change.
Since the change in thermal conditions and atmospheric moisture occurs in all directions along the surface of the Earth, therefore, on land there are two main variants of zonality:
1. Horizontal zoning
2. Vertical zoning
Horizontal zoning exists in two forms:
a) latitudinal zonality;
b) meridional zoning.
Vertical zonation presented on land altitudinal zoning.
Zoning in the oceans
In the World Ocean, zonality is expressed in the existence of surface and bottom oceanic belts.
Variants of zoning in the World Ocean
All variants and types of zonality presented above are also observed in the World Ocean. Vertical zoning in the oceanosphere exists in the form deep zonality of the bottom (provincial zonality).
Horizontal zoning
The phenomenon of horizontal zonality reveals itself in the form of latitudinal and meridional zonality.
Latitudinal zoning
Latitudinal zonality in physical geography is a complex change in zonal natural phenomena and components (climate, soil and vegetation cover, hydrographic conditions, lithogenesis) in the direction from the equator to the poles. This is a general idea of latitudinal zonality.
In addition to such an integrated approach to this variant of zonality, we can talk about the zonality of a single component of nature or a separate phenomenon: for example, the zonality of the soil cover, the zonality of precipitation, bottom silt, etc.
Also in physical geography, there is a landscape approach to latitudinal zonality, which considers it as a change in natural zones on land (and their landscapes in particular) and / or ocean belts in the World Ocean from the equator to the poles (or in reverse direction).
Latitudinal zonality on land
The amount of incoming solar radiation varies with latitude. The closer a territory is to the equator, the more radiation heat it receives for each square meter. With this, in general terms, the phenomenon of latitudinal zonality is connected, which, from a landscape point of view, manifests itself in the fact that natural zones replace each other in latitude. Within each zone, latitudinal-zonal changes are also noticeable - in connection with this, any zone is divided into three subzones: northern, middle and southern.
From the poles to the equator, the average annual air temperature with each degree of latitude increases by about 0.4-0.5 degrees Celsius.
If we talk about the heating of the earth's surface by solar radiation, here it is necessary to make some clarifications. Not the amount of radiation received from the Sun itself determines the temperature regime of the area, but the radiation balance, or residual radiation, that is, the amount of solar energy remaining after the deduction of terrestrial radiation that leaves the surface without benefiting it (i.e. not spending on landscape processes).
All the radiation that comes from the Sun to the Earth's surface is called total shortwave radiation. It consists of two parts - direct radiation and scattered. Direct radiation comes directly from the solar disk, diffuse - from all points in the sky. Also, the surface of the Earth receives radiation in the form of long-wave radiation of the earth's atmosphere ( counter radiation of the atmosphere).
Some of the total solar radiation is reflected ( reflected shortwave radiation). Hence, not all the total radiation is involved in surface heating. The ability to reflect (albedo) depends on the color of the surface, roughness and other physical characteristics. For example, the albedo of pure dry snow is 95%, sand - from 30 to 40%, grass - 20-25%, forests - 10-20%, and black soil - 15%. The total albedo of the Earth is approaching 40%. This means that the planet as a whole "returns" to the Cosmos less than half of the total solar radiation coming to it.
The surface heated by the rest of the total radiation ( absorbed radiation), as well as counterlong-wave radiation of the atmosphere, begins to emit long-wave radiation itself ( terrestrial radiation, or own radiation of the earth's surface).
As a result, after all the "losses" (reflected radiation, terrestrial radiation), the active layer of the Earth is left with some part of the energy, which is called residual radiation, or radiation balance. Residual radiation is spent on all landscape processes: soil and air heating, evaporation, biological renewal, etc.
The sun's rays can affect the ground up to a maximum depth of 30 meters. This is a common maximum for the entire Earth, although different climatic zones have their own maximum penetration of solar heat into the soil. This layer of the earth's crust is called solar thermal, or active. Below the maximum base of the active layer there is a layer of constant annual temperature ( neutral layer). It has a thickness of several meters, and sometimes - tens of meters (depending on the climate, the thermal conductivity of the rocks and their dampness). After it begins the most extensive layer - geothermal extending throughout the earth's crust. The temperature in it is determined by the internal (endogenous) heat of the Earth. From the maximum sole of the neutral zone, the temperature rises with depth (on average - 1 degree Celsius per 33 meters).
The latitudinal zonality has cyclical spatial structure - the types of zones are repeated, replacing each other in the direction from south to north (or vice versa - depending on the starting point). I.e in every belt one can observe a gradual change of landscape zones - from forest to desert. The existence of such cyclicity (especially in the tropical geographic zone) contributes to the interlatitudinal (zonal) circulation of the atmosphere. The mechanism of such a circulation directly or indirectly divides the entire surface of the Earth into dry and wet (or relatively wet) belts, which alternate from the equator to the poles. The equatorial strip turns out to be humid, purely tropical - generally dry, temperate - relatively wet, and the polar belts - relatively dry. On the whole, these zones of atmospheric humidification correspond to the largest natural zones (extensive forests and deserts) of the main climatic zones (equatorial, tropical, temperate, polar).
arctic belt It is characterized by two types of deserts (ice and arctic), tundra (the northern analogue of the steppe), forest-tundra (similar to the forest-steppe) and even the forest zone - the northern and partly the middle taiga. This type of forest landscape is an extremely oppressed type of forest that develops under conditions of fairly low temperatures throughout the year. The difference between the northern taiga and the forests of temperate latitudes is approximately the same as the difference between the forests of the latter and the equatorial forests.
AT temperate zone natural zonality is already observed in its full form, in contrast to the Arctic, the type of landscapes of which is regulated not by a combination of heat and moisture, but by the temperature factor. It is the low temperatures of the Arctic belt that hinder the development of classical natural zones in this polar region.
subtropical belt it is singled out from the temperate and tropical, and exists as an independent only because zoning in it is also developed according to the classical scheme - from deserts to forests (dry Mediterranean and humid monsoon). This is a very interesting phenomenon, because in general the subtropics are a transition zone that exists at the junction of two largest regions that differ in geographical types of air masses. For example, regions with an equatorial climate cannot be singled out as an independent landscape belt only because of the inferior development of zoning.
Latitudinal zonality in the World Ocean
The surface of the World Ocean (and even its bottom), however, is also not free from the influence of climate. In the Ocean, in accordance with climatic zones, oceanic surface water landscape belts(which differ from each other, first of all, in water temperature, as well as in the mode of movement of water masses, salinity, density, organic world, etc.), replacing each other in the latitudinal direction.
The names of the oceanic zones correspond to the names of the climatic zones that cross the ocean: oceanic temperate zone, oceanic tropical zone, etc.
The physical and chemical state of ocean water is projected onto the bottom (similar to the effect of the atmosphere on land). This is how they are formed bottom oceanic belts, which also replace each other in latitude and are distinguished on the basis of differences in bottom sediments.
Thus, the belts in the Ocean (surface and bottom) can be compared with geographical belts on land.
Causes of violation of the horizontal structure of latitudinal zonality on land
It would seem that the world law of latitudinal zonality should establish a clear latitudinal-zonal change of landscape belts and zones on the Earth. This should be favored by a completely correct zonal distribution of solar radiation and interlatitudinal air exchange, which determines the alternation of dry and wet belts. However, the real picture of the alternation of landscape zones is far from such an impeccable scheme. And if the belts somehow "try" to match the parallels, then most of the zones not extending in perfect strips along the parallels to cross the whole continent from west to east; they are represented by broken areas, often have an irregular shape, and in some cases even have a submeridional (along the meridians) strike. Some zones gravitate towards the eastern parts of the continents, others towards the central and western sectors. And the zones themselves as a whole are devoid of internal homogeneity. In a word, we have a fairly complex zonal pattern, which only partly corresponds to the theoretically correct pattern.
The reason for this "nonideality" lies in the fact that the Earth's surface is to a certain extent not uniform in the azonal plan. There are three fundamental geological reasons that influence the "wrong" location and strike of natural zones:
1. The division of the earth's surface into continents and oceans, and uneven
2. Division of the earth's surface into large morphostructural landforms
3. Diverse material composition of the surface, expressed in the fact that it is composed of various rocks
The first factor contributes to the development of meridional zonality; the second factor - vertical (in particular, altitudinal) zonality; the third factor is "petrographic zoning" (conditional factor).
Meridional zoning (on land)
The surface of the Earth is divided into continents and oceans. In the deepest antiquity, there was no land, the entire planet was covered with sea water. After the appearance of the first continent, the coexistence of continents, islands and oceans was not interrupted, only their mutual arrangement changed. Further continental ocean pattern will, of course, change due to never-ending tectonic movements (horizontal and vertical), and with it the pattern of zoning.
Meridional zoning- change of landscape zones from oceanic coasts towards the central parts of the continents. Longitudinal changes in nature are also traced inside the zones. This phenomenon owes its existence to the continental-ocean transport of air masses and sea currents.
It makes sense to consider meridional zonality only on land, since this phenomenon is devoid of expressiveness on the surface of the ocean.
The role of continental-oceanic transport of air masses in the development of meridional zonality on land
Continental-ocean transport of air masses clearly manifests itself in monsoons - powerful currents of air moving in the summer from the ocean to the mainland. The mechanism of formation and development of monsoons is very complex, but its fundamental principles can be summarized in a simplified scheme, which looks like this.
The surface of water and land is different physical characteristics, in particular, thermal conductivity and reflectivity. In summer, the surface of the oceans heats up more slowly than the surface of the land. As a result, the air over the ocean is colder than over land. There is a difference in air density, and hence in atmospheric pressure. Air always moves in the direction of lower pressure.
According to the method and place of formation, monsoons can be divided into two types - tropical and extratropical. The first type is an integral part of the mechanism of interlatitudinal (zonal) circulation of the atmosphere, the second type is a pure continental-ocean transport of air masses.
In winter, the opposite process is observed. The land cools rapidly, and the air above it is greatly cooled. The ocean, which slowly warmed up throughout the summer, also slowly gives off heat to the atmosphere. As a result, the atmosphere over the ocean in winter is warmer than over land.
This is the general picture of the seasonally changing transport of air from the ocean to the mainland and vice versa. For us, the first is more important.
The air moving in summer from the ocean to the mainland carries a huge amount of moisture and in most cases insulates the areas of the continents close to the coasts. Therefore, the coastal parts, where such air transport is observed, are generally wetter and slightly warmer than the central territories (in particular, the difference between summer and winter temperatures is smoothed out).
As you can see, in winter the direction of the air changes to the opposite, and, consequently, in the cold season, the coastal territories of the mainland are dominated by dry and cold continental air.
From this position, we can conclude that the farther the area is from the ocean, the less it gets sea moisture in warm time of the year. However, this statement is true only for the continent of Eurasia, which is extremely elongated from west to east. In most cases, high mountain ranges prevent the penetration of sea air moisture from the ocean to the middle parts of the mainland (the nature of the distribution of precipitation of marine origin over the surface of the mainland is influenced not only by the size of the mainland and its relief, but also mainland configuration; these factors will be discussed later).
The role of sea currents in the development of meridional zonality on land
The ocean influences the continents not only with its air masses, which form over the same water areas (in constant and seasonal baric systems) and move with the help of the general atmospheric circulation mechanism. Continents are also affected sea currents.
The geographical approach to the analysis of climatic nuances obliges us to divide all the currents observed in the World Ocean, first of all, into:
Warm;
cold;
Neutral.
warm currents, moving relatively warm sea air along the coastline of the mainland, provoke an increase in convection (upward air currents) and thereby contribute to heavy precipitation over the coastal regions of the continents and smooth out the difference in air temperature between winter and summer. In this paragraph, it is worth mentioning the famous Gulf Stream, which originates in the warm waters of the Gulf of Mexico and moves along west coast Europe - up to Murmansk. Western Europe, with its mild, warm, humid maritime climate, owes much to this current, the action of which weakens in an easterly direction (toward the Urals). For comparison: the cold Labrador Current, encircling the Canadian peninsula of the same name, makes its climate much colder and drier than the European one, although this region of Canada lies at the same latitudes as the countries of northern and central Europe.
cold currents, moving relatively cold sea air along the mainland coast, provoke a weakening of convection and thereby contribute to the drying of coastal air and an increase in the temperature contrast between winter and summer.
Neutral currents do not introduce any significant amendments and additions to the zonal climate picture of the continents.
Factors affecting the nature of the distribution of sea moisture over the surface of the continent
Three main factors influence the distribution of the moisture of sea air (precipitation of marine origin) over the surface of the mainland (and, in particular, how far humid sea air will move towards the middle parts of the mainland):
1. Relief of the mainland (especially high peripheral ridges)
2. The size of the mainland
3. Mainland configuration
(All of the following applies not only to moist sea air that moves from the ocean to the mainland, but also to warm ocean currents that increase convection).
Peripheral relief called the relief of the marginal parts of the continents. Moist sea air moving from the ocean to the mainland can be blocked by a high mountain range that runs along (parallel to) the coastline. This is called the barrier effect.
The opposite effect is extremely rare and on a limited scale, when mountain ranges located parallel to each other (submeridional or sublatitudinal) act as conductors of moist sea air towards the center of the continent. In relation to the coastline, such ridges should be located perpendicular or at a slight angle.
Mainland size- a significant factor, but it is still worth considering as exceptional. The one and only continent on Earth is characterized by enormous size - Eurasia. It goes without saying that sea air loses almost all moisture on its way to its middle parts.
(The essence of this factor is that sea moisture not can reach the territories of the mainland, which are at a very distant distance from the oceans).
Mainland Configuration defined as his outline, which consists of two components:
1. General outline (all kinds of narrowing and expansion of the continent in certain parts, the degree of elongation in the latitudinal or meridional direction, etc.)
2. Peripheral outline (general indentation of the direct coastline of the continent)
Configuration Factor not independent; it obeys the two previous conditions (in particular, the factor of the size of the continent), as well as many other unique physical and geographical "nuances" (regional and local) characteristic of a particular region of the Earth. Naturally, moist sea air can move further towards the center of the mainland in those places where the mainland narrows or where there is a vast horizontal depression in the form of a marginal or semi-enclosed sea, as well as an oceanic bay.
Expression of meridional zonality on land
Meridional zonality on land is expressed in the existence of so-called landscape sectors.
In connection with the continental-oceanic transport of air masses, all geographic zones, except for the equatorial one, are divided into landscape sectors,which correspond climatic regions.
In each geographical zone, there are oceanic (western and eastern), central and intermediate sectors. And, as already mentioned, one or another type of natural zone tends to the corresponding sector. Since the eastern oceanic sectors of the continents are more humidified (due to the pronounced activity of monsoons and the passage of warm currents) than the western oceanic sectors, forest landscapes gravitate precisely to the eastern margins of the continents (when both in the western oceanic and central parts there is a predominance of desert and steppe PCs). The only exception is Eurasia, where both the western and eastern margins are practically the same in terms of the degree of atmospheric moisture.
Although such a scheme is not universal, the only correct law.
Vertical zonation
Vertical zoning (or landscape layering) is a change in the properties and components of the landscape sphere (terrestrial and bottom-oceanic) depending on the relief.
On Earth, this variant of zoning exists in two forms:
1. Altitudinal zoning (typical for land)
2. Deep zoning (characteristic of the ocean and seabed)
Altitudinal zoning
Hypsometric role of large landforms in the zonal differentiation of land
The reason for the altitudinal zonality is the division of the land surface into morphostructures (large landforms caused by endogenous processes).
Altitudinal (hypsometric) zoning is a change in the properties and components of the terrestrial landscape sphere depending on the relief, that is, with a change in the position of the terrain relative to the average level of the Ocean.
Altitudinal zonality is directly related to the change in air temperature and precipitation as the absolute height increases. With an increase in the height of the terrain, the temperature decreases, and the amount of precipitation in certain places and up to a certain height increases. In general, the arrival of solar radiation increases with height, but the long-wavelength effective radiation also increases to an even greater extent. This is the reason for the decrease in temperature by 0.5-0.6 degrees for every hundred meters of height. The increase in precipitation occurs due to the fact that the air, moving up, is cooled and thus freed from moisture.
Hypsometric (altitude) effect can be traced already on the plains. At higher elevations, the borders of landscape zones are thus pushed to the north. The lowlands favor the advancement of their borders in the opposite direction. Thus, uplands and lowlands largely contribute to changing the boundaries of landscape zones, increasing or decreasing their area.
In the mountains, horizontal zonality disappears; it is replaced by altitudinal zonality. High-altitude belts can be conditionally called analogues of classical natural zones. The phenomenon of altitudinal zonality is part of a general geographical pattern - altitudinal zonality, which is expressed in general changing nature with absolute height.
The ideal scheme of altitudinal zoning is a smooth transition from horizontal zonation to altitudinal zonality- and further to the last mountain belt characteristic of a certain mountainous country. In a simplified form, such a transformation can be represented as follows. One or another part of any natural zone, having reached a certain height (several hundred meters) above sea level, begins to gradually "turn" into a high-altitude (mountain) belt - due to the inevitable decrease in air temperature (and sometimes - with an increase in precipitation) . Ultimately, the zone is replaced altitudinal belt. The territory continues to rapidly "gain height", and the first belt is replaced by the next (and so on until the very last mountain belt).
On vast plains where lowlands and uplands alternate (for example, on the Russian Plain), natural zones, of course, cannot "step over" the boundary after which the zone could turn into an altitudinal belt. But anyway high-altitudezoning- this is a general change in terrestrial nature with a decrease and / or increase in the height of the terrain. And in this regard, in fact, it does not matter whether the natural zone has been transformed into an altitudinal zone or not.
On the other hand, we can also say that "full-fledged" altitudinal zoning begins where a certain part of the zone has crossed a certain boundary, beyond which the absolute height can have a serious cooling effect on landscapes. Within the first hundreds of meters from sea level, such an effect is almost not noticeable, although it is still recorded.
The development of altitudinal zoning is promoted by the division of the earth's surface into morphostructures - into plains and mountains of different heights. The land, therefore, has a multi-tiered structure. Plains belong to two altitudinal tiers - uplands and lowlands. The mountains have a three-tier structure: low-mountain tier, mid-mountain, high-mountain. Under this structure of the earth's surface, natural zones are adjusted, gradually changing and subsequently, reaching a certain climatic line, transforming into altitudinal zones.
Orographic role large forms relief in the zonal sushi differentiation
It has been discussed above hypsometric role large landforms in the landscape differentiation of the natural environment. But morphostructures affect the change in the properties of the zonal structure of the earth's surface not only with the help of the hypsometric (altitude) factor, but alsoalso with the help of three additional effects:
barrier effect;
- "tunnel" effect;
Slope orientation effect.
essence orographic role is that the morphostructures "at their own discretion" redistribute atmospheric and radiative heat, as well as atmospheric precipitation over the Earth's surface.
Strictly speaking, the orographic features of large landforms have practically nothing to do with the phenomenon of altitudinal zoning as such. The analysis of the orographic factor could be taken out of the scope of the topic in which the altitudinal zonality itself is studied directly. But, on the other hand, we, for obvious reasons, cannot confine ourselves to only considering the absolute height factor when studying the role of large landforms in the zonal differentiation of land.
barrier effect It manifests itself in the fact that high and medium-altitude mountain ranges prevent the penetration of warm or cold, wet or dry air masses into any territory. The effect of the barrier depends on the height of the mountain ranges and their extent. In the Northern Hemisphere, the sublatitudinal (along the parallels) strike prevents the advance of air masses from the Arctic (for example, the Crimean Mountains, which trap cold air masses and make the climate of the southern coast of Crimea subtropical). Submeridional (along the meridians) strike prevents the penetration of air, for example, from the oceans.
Plains also have a barrier effect, but to a much lesser extent.
However, not always high mountains act as only barriers. In some cases, they act as conductors, or tunnels, for certain air masses. This contributes parallel arrangement spines relative to each other. And here again we can recall the Cordillera of North America. The ridges of this mountain system are generally parallel to each other, and this favors the penetration of cold arctic air far south, as far as Mexico. Therefore, the climate of the central states of the United States is generally colder than the Mediterranean, and yet these regions have the same distance from the poles. This feature of the relief of North America largely contributes to the submeridional strike of landscape zones in the center of the continent.
An additional factor in the differentiation of the mountains themselves (and, to a lesser extent, the plains) is slope orientation in relation to the cardinal points - that is, insolation and circulation orientation. Windward slopes tend to receive more rainfall, while southern slopes receive more sunlight.
More about altitudinal zonality (mountain zonality)
Phenomenon altitudinal zonality is an part altitudinal zonation.
altitudinal zonality can only be seen in the mountains. Since the absolute height of points on the surface of any mountain system changes quite quickly, the change of climatic elements occurs there sharply and rapidly. This causes a rapid change of altitude belts in the vertical direction. Sometimes it is enough to walk or drive a few kilometers to find yourself in a different altitude zone. This is one of the main differences between mountain zonality and lowland zonality.
Mountain systems differ from each other:
1. The number of high-altitude zones
2. The nature of the change in altitude zones
(Landscape types of belts are the same for all mountains).
Number (set) of altitudinal belts depends on several factors:
The positions of the mountain system in the zonal-belt structure;
Mountain heights;
Horizontal profile (plan) of a mountainous country.
The position of the mountain system in the zonal-belt structure is a fundamental factor. Simply put, this is the position of a mountain system in a certain geographical belt and zone. If, for example, the mountains are located in the forest zone of the tropical geographical zone and if they are high enough, then, naturally, in this case, the mountainous country has the entire set of altitudinal belts. In the temperate geographical zone, even if the mountains are very high, all stages of changing types of mountain landscapes are not observed, since the belts start from one or another natural zone of the temperate zone (in the zonal-belt structure of the temperate zone, by definition, there cannot be any tropical-subtropical forests , nor other types of natural complexes characteristic of the mountains of the tropical belt).
Thus, the set of belts initially depends on which geographical zone, geographical sector and geographical zone the mountains are located in.
Mountain height is also an important factor. In the same equatorial or subequatorial zone, the ancient low mountains will never acquire, for example, mountain coniferous-deciduous forests, and even more so the nival belt - the zone of eternal snow and glaciers.
Horizontal profile (plan) of the mountain system- this is the relative position of the ridges and their orientation in relation to the sun and the prevailing winds. But this factor largely depends on the nature of the change in altitude zones, by which we mean the following features:
- "speed" of changing belts;
The nature of their relative position;
Absolute heights of the upper and lower boundaries of the belts;
Belt outlines;
Belt sizes;
The presence of gaps in the classical sequence (and other features).
If different mountains are located in the same conditions of the zonal-belt structure, have similar altitudinal characteristics, but differ greatly in horizontal profile (plan), then the nature of the change of belts and the general contrast of the landscape-belt pattern will be different.
To a lesser extent, the number of altitudinal belts depends on the horizontal profile.
The above factor, even within the same mountain system, strongly affects landscape differentiation. In different parts of the mountainous country, there is a spectrum of belts, their own character of their change.
In addition, a mountainous country can cross several natural zones and even several natural belts. All this seriously complicates the differentiation of landscapes within the same mountain system.
Altitudinal zonality can be considered as altitudinal-zonal superstructure in the general scheme of the horizontal-zonal series of any region of the Earth.
The types of altitudinal belts are conditionally identical to the types of flat landscape zones and they are replaced in the same sequence as the zones. But in the mountains there are high-altitude belts that have no analogues on the plains - alpine and subalpine meadows. These landscapes are peculiar only to mountains due to the climatic and geological uniqueness of mountainous countries.
The names of the types of altitudinal belts, in principle, correspond to the names of the types of flat zones, only the word "mountain" is attributed to the designation of the mountain belt: mountain-forest belt, mountain-steppe, mountain-tundra, mountain-desert, etc.
Provincial zoning ocean floor
Part of the vertical zonality (landscape layering) is provincial zonality of the ocean floor (bottom provinciality).
Bottom provinciality is a change in the nature of the ocean floor in the direction from the mainland (or island) coasts to the middle parts of the oceans.
This phenomenon exists mainly due to two interrelated factors:
1. Increasing removal of the bottom from the ocean surface (increase in depth)
2. Increasing removal of the bottom directly from the continents or islands
Consider the essence of the first factor. The greater the depth, the less sunlight and atmospheric heat penetrate to the bottom of the ocean (or sea). Light and heat are of great importance for the bottom-ocean version of the landscape sphere. All zonal physical and geographical processes (biological, hydrological, lithological, etc.) occurring at the bottom of the Ocean and in the near-bottom layer of sea water are associated with their number.
But bottom provinciality not is the result solely of an increase in depth. In many respects it is connected with other reasons - in particular, with how far the section of the ocean floor is from the nearest continent or large island. This factor largely determines the features of bottom sedimentation, which change significantly as the bottom moves away directly from the mainland coasts.
Deep layers of the ocean floor
ocean floor has five deep tiers:
1. Littoral
2. Sublittoral
3. Batial
4. Abyssal
5. Ultraabyssal
Littoral- this is a tidal zone; it can fluctuate over a wide range - depending on the evenness of the coast.
sublittoral- this is a zone located below the low tide and corresponding to the shelf of the mainland. It is the most active and organically diverse part of the ocean floor. It reaches depths of 200 to 500 meters.
Batial- the zone of the seabed, approximately corresponding to the continental slope (depth limits - 200-2500 meters). The organic world is much poorer than the previous area.
abyssal- the deep-sea surface of the ocean floor. In depth, it corresponds to the bed of the ocean. Here, bottom waters do not move as fast as surface waters. The temperature is holding all year round around 0 degrees Celsius. sunlight practically does not reach these depths. Of the plants, only some bacteria can be found, as well as saprophytic algae. The thickness of geological deposits in this part of the oceans consists mainly of various organogenic silts (diatom, globigerine) and red clay.
Ultraabyssal parts of the bottom are in the gutters. These depths have been studied very little.
Expression of bottom provinciality
At the regional level, this pattern is expressed in the existence bottomoceanic provinces, each of which approximately corresponds to a certain depth tier of the ocean floor (since the depth factor is decisive).
The bottom provinces should not be confused with bottombelts, replacing each other in latitude, the formation of which is associated with the influence of interrelated factors of latitudinal zonality on the bottom of the World Ocean.
Important: the bottom province is part bottom oceanic belt.But the fundamental difference between them lies in the fact that bottom provinces (unlike bottom belts) differ not only by the nature of lithogenesis and sediments, but also by the features of the organic world, physical and chemical properties bottom layer of water.
So, in each bottom oceanic belt, the following bottom provinces are formed in approximate accordance with the deep tiers:
Sublittoral provinces;
Bathyal provinces;
Abyssal provinces;
- (ultraabyssal provinces).
Bottom provinces replace each other in the direction from the continental coasts to the middle parts of the Ocean. This phenomenon is called provincial zonality of the ocean floor.
Bottom provinciality is a phenomenon that is inherent only in the bottom of the oceans. With some degree of relativity, it can be defined as deep zoning. Continuing this idea, we can state that from the landscape point of view it is wrong to talk about the deep zonality of the water column of the ocean or sea. Although from a purely hydrological point of view, such a phenomenon has the right to exist.
"Petrographic zoning"
All the factors discussed above affected a particular area through climate - solar radiation and air flows with certain meteorological qualities (humidity, temperature, etc.). That is, they were climatic in nature. But it turns out that the material composition and geological structure of the near-surface strata of the earth's crust also have great importance in landscape differentiation. Here all the chemical and physical properties of rocks play a role, on which the hydrogeological features of the territory also depend. Only the phrase "petrographic zoning" is not complete in terms of zoning itself, since this phenomenon does not play a decisive role in the placement of natural zones on the earth's surface, but only changes the configuration of the latter. and general zonal pattern, due to the diverse petrographic composition, takes on an even more complex form than if the entire surface were composed of any one rock (for example, clay or sand). This pattern is very clearly seen in the mountains, where rocks replace each other very quickly and, at times, unpredictably.
On the plains, landscapes that include, in addition to classical sandy and clayey rocks, more nutritious (carbonate) are able to significantly push the boundaries of the temperate zones to the north and thereby expand their area. You have to go far for examples. Izhora plateau near St. Petersburg is composed of limestone Ordovician period on which fertile soils were formed and subsequently a mixed forest was formed, characteristic of more southern regions.
Sands can push the taiga zone far to the south, up to the southern border forest-steppe zone, into which the real coniferous forests.
If you look at this phenomenon from a slightly different angle, it turns out that any zone has such a quality as landscape preview. Its essence lies in the fact that no zone begins or ends abruptly, it always appears in the form of isolated blotches or branches in the more northern zone and disappears with similar blotches in the more southerly one. For example, in the taiga there are patches of mixed forests; there are also copses in the steppes, consisting of coniferous and deciduous trees. Steppe landscapes can be observed in mixed forests, which gradually disappear into semi-deserts. Etc. In any zone, you can find islands of neighboring regions. This phenomenon is also called extrazonality. The reasons for it, in addition to the petrographic properties of the surface, can also be explained by the different exposure of macro- and meso-slopes, which are also characteristic of large plains.
In terms of the impact on the general zoning scheme, the material composition turns out to be equal to the hypsometric factor on the plains.
A z o n a l l o s t
The processes observed directly on the Earth's surface are not only of an exogenous (solar) nature. In the upper part of the earth's crust, a number of phenomena are found, which are an external continuation of the deep geological processes occurring in the depths of our planet. Such surface disturbances are called azonal because they do not belong to the category of zonal processes that are triggered by short-wave electromagnetic solar radiation (when it comes into contact with the day surface).
Azonality in physical geography is defined as a set of interrelated geological phenomena on the surface of the Earth, due to the energy of endogenous processes.
Specifics of azonal phenomena
There are not so many azonal phenomena. They are wholly and completely tectonic movements. They can be divided according to different criteria.
By direction, tectonic movements are divided into:
Vertical movements;
horizontal movements.
According to the impact on the initial occurrence of rocks:
Slow epeirogenic (do not lead to a significant disturbance of the bedding of rocks);
Dislocation movements (cause various discontinuous and folded deformations of rocks - horsts, grabens, faults, thrusts, orogenic synclines and anticlines).
Tectonic movements serve as a trigger for the emergence of seismic and magmatic (intrusive and effusive, or volcanic) phenomena, which are also related to azonal.
In the depths of the Earth, geological processes for some reason proceed with different intensity. Because of this, some parts of the earth's crust receive more energy for further evolution, while others (relatively formed) receive much less. Consequently, the tectonic movements of the earth's crust in its different parts differ from each other in strength, speed and direction. This difference ultimately leads to the formation on land (and the bottom of the ocean) of large landforms (plains and mountains), which are called morphostructures.
There is such a thing as order morphostructures. Later we will see that it is this concept that is of great importance for the azonal physiographic zoning of land.
Morphostructures of various orders
It will not be superfluous to repeat: morphostructures are large landforms, the genesis of which is dictated by intraterrestrial energy. They are constituent parts tectonic structures (geostructures). When morphostructural zoning of the land surface, one should take into account the fact that the order of the morphostructure must coincide with the order of the tectonic structure.
Morphostructures of higher order
mainland ledges and ocean trenches – tectonic structures highest order. If they are considered from a morphostructural point of view, then these forms of the Earth's megarelief are called geotectures.
Morphostructures of the 1st order on the continents. ancient platforms
The continents are composed of geostructures of the 1st order:
Platforms (ancient and young);
Movable belts.
In accordance with this division, the morphostructures of the 1st order in the platform areas are the vast plains, which on the ancient platforms cover both plates and shields (and, accordingly, occupy almost the entire area of the ancient platforms).
The ancient platforms are mostly plains; mountains are quite rare. There are three categories of platform mountains:
1. "Relic":
a) remnants (isolated sharp ledges of rocks left after the destruction of less stable rocks of the area) - ancient residual mountains;
b) ancient extinct volcanoes.
2.
Denudation:
a) erosive (table) mountains (arising from the erosive dismemberment of uplifts on shields and anteclises);
b) prepared ("exposed") igneous formations (structural-denudation mountains).
3. Epiplatform (blocky mountains)
Thus, on ancient platforms, "relict" mountains include solitary extinct volcanic cones (extremely rare) and remnants. Remnants and volcanoes are most often part of the platform highlands, which will be discussed below. In addition, the Precambrian platforms are characterized by denudation (erosion and prepared) mountains.
But there is another (third) category of platform mountains. These are rocky mountains. The sites of some ancient platforms that experienced epiplatform orogeny in the Cenozoic are also characterized by mountainous relief, which is represented by short low blocky ridges. Such ridges are combined with elevated plains (plateaus, plateaus, etc.). The morphological complex of blocky ridges and elevated plains is often complicated by isolated mountains (extinct or active volcanoes, as well as remnants). That is, in the horizontal plan, these territories have a rather "chaotic", irregular shape. Because of this, they are called highlands (or plateaus).
Mountains of ancient platforms are found mainly on shields.
Morphostructures of the 2nd order on ancient platforms
Ancient platforms consist of tectonic structures of the 2nd order:
Plates;
Shields.
As a rule, the entire area of any plate is occupied by a vast plain - a system of uplands and lowlands, merged into one flat complex. Such a complex is called flat country(for example, the Russian plain country, which occupies the East European platform of the same name) and is a second-order morphostructure.
Any massive shield of one or another ancient platform (for example, the Baltic Shield of the East European Platform) in most cases also corresponds to a generally uneven plain complex, which may consist of elevated basement plains, uplands and plateaus. Such a vast plain complex is also considered a platform morphostructure of the 2nd order.
Morphostructures of the 3rd Order on Slabs of Ancient Platforms
This or that plate of the ancient platform breaks up into syneclises, anteclises, aulacogens and some other tectonic structures of the 3rd order. Syneclises are extensive troughs in the earth's crust. They correspond lowlands. Anteclises are large uplifts in the earth's crust. In the relief they are expressed hills. Lowlands on syneclises and uplands on anteclises are morphostructures of the third order.
Morphostructures of epigeosynclinal mobile belts
Three types of mobile belts exist within the continents: epigeosynclinal, epiplatform, and rift (modern active rifts).
Any epigeosynclinal belt in itself is a mobile geostructure of the 1st order. It can be divided into epigeosynclinal regions - tectonic structures of the second order, which correspond to mobile morphostructures of the 2nd order - mountain countries. For example, the Alpine-Himalayan belt is divided into the following areas: the Alps, the Pyrenees, the Greater Caucasus, the Himalayas, the Carpathians, etc. In morphostructural terms, they are mountainous countries.
Expression of azonality on land
If zonality on land finds expression in the existence of landscape zones, then azonality fully manifests itself in the form landscape countries.
When identifying a landscape country on the land surface, we should not forget that such a unit should have more or less uniform azonal characteristics. at the regional level. This means that the territory must be located within the same form of macrorelief, have more or less the same geological structure, origin, as well as a uniform tectonic regime.
Such requirements on the ancient platform are met morphostructures of the 2nd order that can be presented:
1. Flat country - on the stove
2. A complex of basement plains of different heights, highlands and plateaus - on a massive shield
Within the epigeosynclinal belt, these requirements are met by mountainous countries, which are mobile morphostructures of the 2nd order.
Directly landscape countries are defined as azonal physiographic units of the first order.
Since the morphostructures are a single whole in terms of all azonal characteristics, they are well suited for azonal landscape zoning of land.
landscape countries- the main units of the azonal zoning of the continental surface, which on the ancient platform and within the epigeosynclinal belt are almost always distinguished on the basis of morphostructures of the 2nd order.
On the plains, countries include segments of various natural zones (zones can also cross several countries), and in the mountains - a set of altitudinal belts.
Landscape countries, according to azonal characteristics, are divided into certain areas, from which azonal physiographic units of the second order are quite clearly distinguished - landscape areas, the boundaries of which on ancient platforms in most cases coincide with the boundaries of morphostructures of the 3rd order (individual uplands, lowlands, etc.).
Landscape areas, in turn, also consist of smaller azonal geosystems.
Some features of the azonal landscape zoning of the East European Platform
The tectonic zoning of the Precambrian East European Platform, acceptable for an adequate physical and geographical zoning of the Russian Federation and neighboring states, provides for its division into several large subordinate geostructures of the 2nd order - the Russian Plate, the Baltic Shield and the Ukrainian Shield.
The Russian plate corresponds to a flat country called the Russian Plain. Within its boundaries is the landscape country of the same name.
The vast Baltic Shield, which occupies a significant part of the area of the Scandinavian Peninsula, all of Karelia and the Kola Peninsula, is physically and geographically a landscape country called Fennoscandia.
The relatively small Ukrainian shield, which, although it is a 2nd order geostructure, not stands out as an independent physical and geographical country. In the theory and practice of landscape science, this shield is considered as a landscape area, which is part of the Russian landscape country. Thus, we see that in the azonal zoning of the continents, the shield of an ancient platform cannot always serve as a basis for distinguishing a landscape country.
Within Russian Federation and adjacent states The Russian Plain includes about twenty landscape areas. Some of them: Central Russian, Upper Volga, Pechora, Polesskaya, Donetsk, Dnieper-Azov (Ukrainian shield), etc.
Fennoscandia within the Russian Federation is called the Kola-Karelian landscape country. As the name suggests, it is divided into two regions - Kola and Karelian.
Intrazonal
The physical-geographical region (landscape), being one hundred percent homogeneous in terms of climate, tectonic regime and located within the same macroform of relief, nevertheless, has a diverse, mosaic horizontal structure, like all other zoning units of higher ranks. A person who has a good feeling for nature, when crossing any terrain, can pay attention to the fact that, for example, plant communities (and in general natural complexes) replace each other literally every few hundred meters of the path. And each of them is unique and inimitable. This is due to the variety morphosculptural basis(geological basement, or morpholithogenic basis) of each individual area.
In the process of geological development, the landscape acquires a unique and, most importantly, heterogeneous morpholithogenic ensemble, under which biocenoses (in particular, phytocenoses) are adjusted over time. The morpholithogenic base is a complex of various morphosculptures (hills, beams, ridges, etc.).
Each morphosculpture in the landscape consists of smaller forms of microrelief (for example, the top of a hill, its slopes, foot, etc.)
Any form of microrelief is characterized by:
1. Microclimate
2. Hydration
3. Nutritional value (trophic) of soil and rocks
One or another phytocenosis "chooses" a certain form of microrelief within one morphosculpture, or ecotope(habitat), the conditions of which correspond to the needs of all plants in climate, moisture and nutritional value of the soil. Therefore, the ecotope consists of:
1. To limatotope (microclimate conditions)
2. Hygrotope (humidity conditions)
3. Edaphotopa (soil conditions)
For example, it is known that swamp vegetation settles in excessively moist places, pines - on poor, dry sandy and sandy loamy soils (and birch generally grows in any conditions). This explains such a variegated picture of natural complexes on a relatively small area of the landscape. Moreover, any physical-geographical region has its own, individual morpho-sculptural complex. This makes the picture of nature even more diverse.
Microclimate
Each individual part of the morphosculpture (called facies in physical geography) - for example, the slopes of a hill, its top, foot - has its own microclimate. The differences in the microclimate of such relatively small natural formations lie in the unequal orientation of the parts of the morphosculpture in relation to the sun's rays and the wind - that is, to the cardinal points. The slopes facing south are always warmer than the opposite slopes. Consequently, in different parts of a hill or gully, all microgeographical processes proceed differently.
Moisturizing
Humidification of the territory consists of three articles:
1. Atmospheric humidification
2. Ground moisture
3. Leaky moisturizing
Atmospheric humidification is a product of climate and has been discussed in previous chapters.
ground moisture
Ground moisture is determined by the level of groundwater, which varies depending on:
a) the geological structure and mechanical composition of the landscape basement (the mechanical composition of the entire rock mass, the nature and sequence of their occurrence);
b) forms meso the topography on which the facies is located.
Rocks that pass water well are called permeable. These include mainly sands and sandy loams. Water not permeable rocks that poorly pass water (clays and heavy loams) or do not pass at all, retain it at the surface, causing excessive moisture in the area. In such places, the groundwater level is always much higher than in those where sandy rocks pass almost all the precipitation through themselves, which, having passed through the thickness of the sand, are quickly removed along with underground runoff (if the general terrain slope).
Negative morphosculptures(ravines, beams, depressions, closed depressions between hills, etc.) almost always have high level groundwater, sometimes coming to the surface. Consequently, plants that need a large amount of moisture settle in these places. Moreover, negative meso landforms, due to their concavity, "take" water from the surrounding territories (water always flows into depressions). This increases the moisture in the area. In such places, swamps or wetlands usually occur.
Positive morphosculptures(hills, ridges, etc.) have low level groundwater, and biocenoses that are unpretentious in relation to moisture are usually formed there. Positive meso landforms, due to their convexity, are constantly freed from "excess" water. And it dries up the area even more.
Depending on the need for moisture, all plants were divided into three groups:
1. Hygrophytes
2. Mesophytes
3. Xerophytes
Hygrophytes are very demanding on moisture.
Mesophytes grow in conditions of moderate moisture (these are the majority of plants in the middle (temperate) zone of Russia and other countries).
Xerophytes can exist in conditions of extreme lack of water (in deserts).
Leaky moisturizing
This type of moisture is associated with flow water, which can be caused by surface runoff of rain and melt water (under the action of gravity), floodplain overflow of watercourses (during floods and floods), influx of water as a result of tides. Depending on this, leakage moisture is divided into three types:
1. Deluvial (surface runoff)
2. floodplain
3. Tidal
Consequently, sinter moisture depends on the relief, the proximity of water bodies and streams.
Soil nutrition
The trophic (nutritional) properties of the morpho-sculptural complex of the landscape are associated with the mineral composition of the soil-forming and underlying rocks. To nutritious rocks include clays, loams, loess and those containing limestone. The poor in terms of nutrition include sands and sandy loams, as well as rocks. Plants have different nutrient requirements. Some of them are quite demanding on the soil, others "do not care" where to grow; and still others are content with little. In this regard, all plants are divided into three groups:
1. Demanding nutrients - megatrophs (eutrophs)
2. Moderately demanding on nutrients - mesotrophs
3. Not demanding on nutrients - oligotrophs
To the trees megatrophs include ash, maple, elm, white willow, walnut, hornbeam, beech, fir; to mesotrophs- aspens, downy birch, black alder, pedunculate oaks, mountain ash, larches and others; to oligotrophs- Scots pines, junipers, white acacias, warty birches, etc.
The nutritional value of the soil can also be related to the chemical composition of groundwater.
Having chosen a habitat (ecotope), the flora and fauna begins to develop according to its own unique laws, forming unique combinations and forms. Moreover, biota (a set of plant, animal and microorganism species in a certain area), while evolving, strongly affects the components of the natural complex. That is why there can be no complete coincidence on facies that are completely identical to each other. Two absolutely identical spruce forests at first glance will turn out to be different in terms of micro- and nanorelief parameters, set and grouping of plants, lifestyle of insects, animals and birds, etc.
Now let's move on to the actual intrazonal. Each landscape contains such natural complexes that reflect its position in the zonal system of the earth's surface. That is, these natural complexes can immediately determine which zone the landscape belongs to. Such geosystems are called upland(automorphic), or typically zonal. They are typical for areas where the microclimate, moisture conditions and trophic properties of the surface are within the average, normal values characteristic of a particular landscape zone. All other geosystems that develop under conditions that deviate significantly from "normal" are called intrazonal. Usually upland PCs predominate over intrazonal ones. But the opposite also happens. And such a phenomenon is far from rare.
In principle, each zone is characterized by its own intrazonal complexes, which are unique to it. Therefore, any zone has its own intrazonal next. Nowhere on Earth will we find intrazonal tropical desert geosystems (oases) in temperate forests. And vice versa, swamps, characteristic of the middle zone of Eurasia and North America, cannot be found in the Sahara or at least the Karakum. The same can be said about mangroves, which are not characteristic of the landscapes of Greenland and Tierra del Fuego.
But the natural complexes characteristic of the neighboring (more northern or southern) natural zone are a frequent and quite natural phenomenon, and it is called extrazonality which has already been discussed above. She, at first glance, is somewhat similar to intrazonal, but the functional causes and effects of these two interesting phenomena are different.
About physical-geographical zoning
In a real situation, landscape zones and countries, of course, do not exist separately, they functionally and territorially complement each other in all respects. Therefore, the main task of the theoretical research of physical geography is to connect them. Combining these regions, one can distinguish derived units in which azonal and zonal characteristics coincide on a regional scale. Such units include the so-called provinces formed from the intersection of zones and countries.
With further zoning within the province, from the "contact" of the remaining segment of the zone with different landscape areas "entering" its territory, provinces of the second order are obtained. Within a province of the second order, the azonal characteristics are already sufficiently homogeneous, but in the zonal plan, it can consist of segments of subzones. A segment of a subzone within a second-order province is defined as a third-order province.
Further, the combination becomes uncertain and unpredictable. In some cases, a province of the third order can still be divided into certain regional "azonal" territories. At the same time, it breaks up, therefore, into provinces of the 4th order. But, of course, this is not always the case. Sometimes azonal criteria divide a 3rd order province directly into landscapes (the most striking example is individual volcanoes or any other volcanic formations of this magnitude; they are all independent landscapes). The last province is thus optional unit existing in some regions and absent in others. The next step after it is landscape area(or simply landscape), which, as we found out, is also distinguished on the basis of azonal differences within the provinces of the 3rd or 4th order.
Carefully analyzing such zoning, you can see that in order to divide a province of a higher order into subordinate provinces of lower ranks, it is necessary to use interleaving approach zonal and azonal indicators. Thus, within the main province, a part of the landscape area stands out; after that, already within the formed province of the second order, the boundaries of the segment of the subzone are determined, which will allow us to establish the limits of the province of the third order. Next, we look for azonal differences again...
So, the most acceptable for us landscape zoning, suitable for both theory and practice, has not a disparate two-linear, but a zonal-azonal structure. It looks very simple: province of the 1st order - province of the 2nd order - province of the 3rd order - (province of the 4th order) - landscape area.
Such a scheme shows that, by gradually narrowing the area of zoning, we will descend from a province of a higher order to a landscape region, throughout the entire space of which there are no zonal or azonal differences. Then it remains only to establish adequate boundaries of the landscape area. This is precisely the main ultimate practical goal of domestic and foreign landscape science.