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. With distance from the Sun, the flow of its rays becomes weaker, and at a sufficiently long 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, although indirectly: it allows the planet (unlike, for example, the "light" Moon) to retain 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 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 near-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 zone is characterized by low atmospheric pressure, calms, ascending air currents, for tropical - high pressure, winds with an eastern component (trade winds), for moderate ones - low pressure, westerly winds, for polar ones - low pressure, winds with an eastern 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 the circulation of the atmosphere, 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, 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. 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. 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 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. 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 zonality 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 suffices 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, throughout 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 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 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 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 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 only 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 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 under 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 entire complex nature of territorial physical and geographical differentiation by it alone.
Landscape zoning- a regular change in physical and geographical processes, components and geosystems from the equator to the poles.
Reason: uneven distribution of short-wave solar radiation due to the sphericity of the Earth and the inclination of its orbit. Zonality is most pronounced in changes in climate, vegetation, wildlife, and soils. These changes in groundwater and lithogenic base are less contrasting.
It is expressed primarily in the average annual amount of heat and moisture at different latitudes. First, this is a different distribution of the radiation balance of the earth's surface. The maximum is at 20 and 30 latitudes, since there is the least cloudiness in contrast to the equator. This implies an uneven latitudinal distribution of air masses, atmospheric circulation and moisture circulation.
Zonal landscape types are landscapes formed under autonomous conditions (upland, eluvial), that is, under the influence of atmospheric moisture and zonal temperature conditions.
Drain Zones:
equatorial zone of abundant runoff.
tropical zones
Subtropical
Moderate
Subpolar
Polar
20. Geographic sector and its impact on regional landscape structures.
Sector Law(otherwise azonal law , or provinciality , or meridionality ) - the pattern of differentiation of the Earth's vegetation cover under the influence of the following reasons: the distribution of land and sea, the topography of the green surface and the composition of rocks.
The sector law is an addition to the law of geographical zoning, which considers the patterns of distribution of vegetation (landscapes) under the influence of the distribution of solar energy over the Earth's surface, depending on the incoming solar radiation, depending on latitude. The law of azonality considers the influence of the redistribution of the incoming solar energy in the form of changes in climatic factors when moving deeper into the continents (the so-called increase in continentality of the climate) or oceans - the nature and distribution of precipitation, the number of sunny days, average monthly temperatures, etc.
Sector of the oceans. Expressed in distribution:
River runoff (desalination of ocean waters).
Receipts of suspended solids, nutrients.
Salinity of waters caused by evaporation from the surface of the oceans.
and other indicators. In general, there is a significant depletion of ocean waters in the depths of the oceans, the so-called oceanic deserts.
On the continents, the sector law is expressed in:
Circumoceanic zonality, which can be of several types:
A) symmetrical - oceanic impact is manifested with the same strength and extent from all sides of the mainland (Australia);
b) asymmetric - where the influence of the Atlantic Ocean prevails (as a result of western transport), as in the north of Eurasia;
V) mixed.
The growth of continentality as you move deeper into the mainland.
21. Altitudinal zonality as a factor of landscape differentiation.
Altitudinal zonality - part of the vertical zonality of natural processes and phenomena, related only to mountains. Change of natural zones in the mountains from the foot to the top.
The reason is the change in heat balance with height. The amount of solar radiation increases with height, but the radiation of the earth's surface grows even faster, as a result, the radiation balance drops, and the temperature also drops. The gradient here is higher than in the latitudinal zonality.
As the temperature drops, the humidity also drops. A barrier effect is observed: rain clouds approach the windward slopes, rise, condense and precipitate. As a result, already dry and non-humid air rolls over the mountain (to the leeward slope).
Each flat zone has its own type of altitudinal zonation. But this is only outwardly and not always, there are analogues - alpine meadows, cold deserts of Tibet and the Pamirs. As we approach the equator, the possible number of these types increases.
Examples: Ural - tundra and the Goltsov belt. Himalayas - subtropical forest, coniferous forest, boreal coniferous forest, tundra. + Eternal snow is possible.
Differences from zones: rarefaction of air, atmospheric circulation, seasonal fluctuations in temperature and pressure, geomorphological processes.
Latitudinal zoning- a regular change in physical and geographical processes, components and complexes of geosystems from the equator to the poles. Latitudinal zonality is due to the spherical shape of the Earth's surface, as a result of which there is a gradual decrease in the amount of heat coming to it from the equator to the poles.
Altitudinal zonality- a natural change in natural conditions and landscapes in the mountains as the absolute height increases. Altitudinal zonality is explained by climate change with height: a drop in air temperature with height and an increase in precipitation and atmospheric moisture. Vertical zonality always begins with the horizontal zone in which the mountainous country is located. Above the belts are replaced in general in the same way as the horizontal zones, up to the area of polar snows. Sometimes the less precise name "vertical zonality" is used. It is inaccurate because the belts do not have a vertical, but a horizontal strike and replace each other in height (Figure 12).
Figure 12 - Altitudinal zonality in the mountains
natural areas- these are natural-territorial complexes within the geographical zones of land, corresponding to the types of vegetation. In the distribution of natural zones in the belt, the relief plays an important role, its pattern and absolute heights - mountain barriers that block the path of the air flow, contribute to the rapid change of natural zones to more continental ones.
Natural zones of equatorial and subequatorial latitudes. Zone moist equatorial forests (hylaea) located in the equatorial climate zone with high temperatures (+28 °C), and a large amount of precipitation throughout the year (more than 3000 mm). The zone is most widespread in South America, where it occupies the Amazon basin. In Africa, it is located in the Congo basin, in Asia - on the Malay Peninsula and the islands of Greater and Lesser Sunda and New Guinea (Figure 13).
Figure 13 - Natural zones of the Earth
Evergreen forests are dense, impenetrable, grow on red-yellow ferralite soils. Forests are distinguished by species diversity: an abundance of palms, lianas and epiphytes; mangrove thickets are common along the sea coasts. There are hundreds of species of trees in such a forest, and they are arranged in several tiers. Many of them bloom and bear fruit all year round.
The animal world is also diverse. Most of the inhabitants are adapted to life on trees: monkeys, sloths, etc. Of the land animals, tapirs, hippos, jaguars, leopards are characteristic. There are a lot of birds (parrots, hummingbirds), the world of reptiles, amphibians and insects is rich.
Savannah and woodland zone located in the subequatorial belt of Africa, Australia, South America. The climate is characterized by high temperatures, alternating wet and dry seasons. Soils of a peculiar color: red and red-brown or reddish-brown, in which iron compounds accumulate. Due to insufficient moisture, the vegetation cover is an endless sea of grasses with isolated low trees and thickets of shrubs. Woody vegetation gives way to grasses, mainly tall grasses, sometimes reaching 1.5–3 meters in height. Numerous species of cacti and agaves are common in the American savannas. Certain types of trees have adapted to the dry period, storing moisture or delaying evaporation. These are African baobabs, Australian eucalyptus, South American bottle tree and palm trees. The animal world is rich and varied. The main feature of the fauna of the savannas is the abundance of birds, ungulates and the presence of large predators. Vegetation contributes to the spread of large herbivorous and predatory mammals, birds, reptiles, and insects.
Zone variable-humid deciduous forests from the east, north and south frames the hylaea. Here, both evergreen hard-leaved species characteristic of gilis, and species partially shedding their leaves in summer, are common; lateritic red and yellow soils are formed. The animal world is rich and varied.
Natural zones of tropical and subtropical latitudes. The tropical zone of the northern and southern hemispheres is dominated by tropical desert zone. The climate is tropical desert, hot and dry, because the soils are underdeveloped, often saline. Vegetation on such soils is sparse: rare hard grasses, thorny shrubs, saltworts, lichens. The animal world is richer than the vegetable world, because reptiles (snakes, lizards) and insects are able to stay without water for a long time. Of the mammals - ungulates (gazelle antelope, etc.), capable of traveling long distances in search of water. Near water sources there are oases - "spots" of life among dead desert spaces. Date palms and oleanders grow here.
Also present in the tropics zone of humid and variable-moist tropical forests. It was formed in the eastern part of South America, in the northern and northeastern parts of Australia. The climate is humid with constantly high temperatures and high rainfall, which falls during the summer during the monsoon rains. On red-yellow and red soils, variable-moist, evergreen forests grow, rich in species composition (palms, ficuses). They look like equatorial forests. The animal world is rich and varied (monkeys, parrots).
Subtropical hard-leaved evergreen forests and shrubs typical for the western part of the continents, where the climate is Mediterranean: hot and dry summers, warm and rainy winters. Brown soils are highly fertile and are used to cultivate valuable subtropical crops. The lack of moisture during the period of intense solar radiation led to the appearance of adaptations in plants in the form of hard leaves with a waxy coating, which reduce evaporation. Hard-leaved evergreen forests are adorned with laurels, wild olives, cypresses, and yews. In large areas they have been cut down, and their place is taken by fields of grain crops, orchards and vineyards.
Humid subtropical forest zone located in the east of the continents, where the climate is subtropical monsoon. Precipitation falls in summer. The forests are dense, evergreen, broad-leaved and mixed, growing on red and yellow soils. The fauna is diverse, there are bears, deer, roe deer.
Zones of subtropical steppes, semi-deserts and deserts distributed in sectors in the interior of the continents. In South America, the steppes are called pampas. The subtropical dry climate with hot summers and relatively warm winters allows drought-resistant grasses and grasses (wormwood, feather grass) to grow on gray-brown steppe and brown desert soils. The animal world is distinguished by species diversity. Of the mammals, ground squirrels, jerboas, gazelles, kulans, jackals and hyenas are typical. Numerous lizards, snakes.
Natural zones of temperate latitudes include zones of deserts and semi-deserts, steppes, forest-steppes, forests.
Deserts and semi-deserts temperate latitudes occupy large areas in the interior of Eurasia and North America, small areas in South America (Argentina), where the climate is sharply continental, dry, with cold winters and hot summers. Poor vegetation grows on gray-brown desert soils: steppe feather grass, wormwood, camel thorn; saltworts in depressions on saline soils. The fauna is dominated by lizards, snakes, turtles, jerboas, and saigas are common.
Steppes occupy large territories in Eurasia, South and North America. In North America they are called prairies. The climate of the steppes is continental, arid. Due to the lack of moisture, there are no trees and a rich grass cover (feather grass, fescue and other grasses) is developed. The most fertile soils are formed in the steppes - chernozem. In the summer the vegetation in the steppes is sparse, and in the short spring many flowers bloom; lilies, tulips, poppies. The fauna of the steppes is represented mainly by mice, ground squirrels, hamsters, as well as foxes, ferrets. The nature of the steppes has largely changed under the influence of man.
To the north of the steppes is a zone forest-steppes. This is a transitional zone, forest areas in it are interspersed with significant spaces covered with grassy vegetation.
Deciduous and mixed forest zones represented in Eurasia, North and South America. The climate, when moving from the oceans into the continents, changes from maritime (monsoon) to continental. Vegetation changes depending on the climate. The zone of broad-leaved forests (beech, oak, maple, linden) passes into the zone of mixed forests (pine, spruce, oak, hornbeam, etc.). To the north and further into the interior of the continents, coniferous species (pine, spruce, fir, larch) are common. Among them there are also small-leaved species (birch, aspen, alder).
The soils in the broad-leaved forest are brown forest, in the mixed forest they are sod-podzolic, in the taiga they are podzolic and permafrost-taiga. Almost all forest zones of the temperate zone are characterized by a wide distribution swamps.
The fauna is very diverse (deer, brown bears, lynxes, wild boars, roe deer, etc.).
Natural zones of subpolar and polar latitudes. forest tundra is a transition zone from forests to tundra. The climate in these latitudes is cold. The soils are tundra-gley, podzolic and peat-bog. The vegetation of light forests (low larches, spruce, birch) gradually turns into tundra. The fauna is represented by the inhabitants of the forest and tundra zones (polar owls, lemmings).
Tundra characterized by arrogance. Climate with long cold winters, wet and cold summers. This leads to severe freezing of the soil, forming permafrost. Evaporation is low here, organic matter does not have time to decompose and as a result swamps are formed. Mosses, lichens, low grasses, dwarf birches, willows, etc. grow on humus-poor tundra-gley and peat-bog soils of the tundra. moss, lichen, shrub. The animal world is poor (reindeer, arctic fox, owls, pied).
Arctic (Antarctic) desert zone located in polar latitudes. Due to the very cold climate with low temperatures throughout the year, large areas of land are covered with glaciers. Soils are almost undeveloped. On ice-free areas there are rocky deserts with very poor and sparse vegetation (mosses, lichens, algae). Polar birds settle on the rocks, forming "bird colonies". In North America, there is a large ungulate animal - the musk ox. Natural conditions in Antarctica are even more severe. Penguins, petrels, cormorants nest on the coast. Whales, seals, and fish live in Antarctic waters.
Similar information.
Everyone knows that the distribution of solar heat on Earth is uneven due to the spherical shape of the planet. As a result, different natural systems are formed, where in each of them all components are closely connected with each other, and a natural zone is formed, which is found on all continents. If you follow the animal in the same zones, but on different continents, you can see a certain similarity.
Law of geographic zoning
The scientist V. V. Dokuchaev once created the doctrine of natural zones, and expressed the idea that each zone is a natural complex, where living and inanimate nature are closely interconnected. Later, on this basis of the teaching, the first qualification was created, which was finalized and more specified by another scientist L.S. Berg.
The forms of zoning are different due to the diversity of the composition of the geographic envelope and the influence of two main factors: the energy of the Sun and the energy of the Earth. It is with these factors that natural zonality is associated, which manifests itself in the distribution of the oceans, the diversity of the relief and its structure. As a result, various natural complexes were formed, and the largest of them is the geographical zone, which is close to the climatic zones described by B.P. Alisov).
The following geographic regions are distinguished by two subequatorial, tropical and subtropical, temperate, subpolar and polar (Arctic and Antarctic). subdivided into zones, which are worth talking about more specifically.
What is latitudinal zoning
Natural zones are closely connected with climatic zones, which means that zones, like belts, gradually replace each other, moving from the equator to the poles, where solar heat decreases and precipitation changes. Such a change of large natural complexes is called latitudinal zonality, which manifests itself in all natural zones, regardless of size.
What is altitudinal zoning
The map shows, if you move from north to east, that in each geographical zone there is a geographical zonality, starting from the Arctic deserts, moving on to the tundra, then to the forest tundra, taiga, mixed and broad-leaved forests, forest-steppe and steppes, and, finally, to the desert and subtropics. They stretch from west to east in stripes, but there is another direction.
Many people know that the higher you climb the mountains, the more the ratio of heat and moisture changes towards low temperature and precipitation in solid form, as a result of which the flora and fauna change. Scientists and geographers gave this direction their name - altitudinal zonality (or zonality), when one zone replaces another, encircling mountains at different heights. At the same time, the change of belts occurs faster than on the plain, one has only to climb 1 km, and there will be another zone. The lowest belt always corresponds to where the mountain is located, and the closer it is to the poles, the fewer these zones can be found at a height.
The law of geographical zoning also works in the mountains. Seasonality, as well as the change of day and night, depend on geographical latitude. If the mountain is close to the pole, then you can also meet the polar night and day there, and if the location is near the equator, then the day will always be equal to the night.
ice zone
Natural zonality adjacent to the poles of the globe is called ice. A harsh climate, where snow and ice lie all year round, and in the warmest month the temperature does not rise above 0 °. Snow covers the entire earth, even though the sun shines around the clock for several months, but does not warm it at all.
Under too severe conditions, few animals live in the ice zone (polar bear, penguins, seals, walruses, arctic fox, reindeer), even fewer plants can be found, since the soil-forming process is at the initial stage of development, and mostly unorganized plants (lichen , moss, algae).
tundra zone
A zone of cold and strong winds, where there is a long long winter and a short summer, because of which the soil does not have time to warm up, and a layer of permafrost soils is formed.
The law of zonality works even in the tundra and divides it into three subzones, moving from north to south: the arctic tundra, where mainly moss and lichens grow, the typical lichen-moss tundra, where shrubs appear in places, is distributed from Vaigach to Kolyma, and tundra, where the vegetation consists of three levels.
Separately, it is worth mentioning the forest-tundra, which stretches in a thin strip and is a transition zone between the tundra and forests.
taiga zone
For Russia, Taiga is the largest natural zone, which stretches from the western borders to the Sea of Okhotsk and the Sea of Japan. The taiga is located in two climatic zones, as a result of which there are differences within it.
This natural zonality concentrates a large number of lakes and swamps, and it is here that the great rivers in Russia originate: the Volga, Kama, Lena, Vilyui and others.
The main thing for the plant world is coniferous forests, where larch dominates, spruce, fir, and pine are less common. The fauna is heterogeneous and the eastern part of the taiga is richer than the western.
Forests, forest-steppes and steppes
In the mixed zone, the climate is warmer and wetter, and latitudinal zonality is well traced here. Winters are less severe, summers are long and warm, which contributes to the growth of trees such as oak, ash, maple, linden, and hazel. Due to complex plant communities, this zone has a diverse fauna, and, for example, bison, muskrat, wild boar, wolf, and elk are common on the East European Plain.
The zone of mixed forests is richer than in coniferous ones, and there are large herbivores and a wide variety of birds. Geographical zonality is distinguished by the density of river reservoirs, some of which do not freeze at all in winter.
The transitional zone between the steppe and the forest is the forest-steppe, where there is an alternation of forest and meadow phytocenoses.
steppe zone
This is another species that describes natural zoning. It differs sharply in climatic conditions from the above-mentioned zones, and the main difference is the lack of water, as a result of which there are no forests and cereal plants and all the various grasses that cover the earth with a continuous carpet predominate. Despite the fact that there is not enough water in this zone, the plants tolerate drought very well, often their leaves are small and can curl up during the heat to prevent evaporation.
The fauna is more diverse: there are ungulates, rodents, predators. In Russia, the steppe is the most developed by man and the main zone of agriculture.
Steppes are found in the Northern and Southern Hemispheres, but gradually they disappear due to plowing, fires, and animal grazing.
Latitudinal and altitudinal zoning is also found in the steppes, so they are divided into several subspecies: mountainous (for example, the Caucasus Mountains), meadow (typical for Western Siberia), xerophilous, where there are many soddy cereals, and desert (they became the steppes of Kalmykia).
Desert and tropics
Sharp changes in climatic conditions are due to the fact that evaporation exceeds many times precipitation (7 times), and the duration of such a period is up to six months. The vegetation of this zone is not rich, and mostly there are grasses, shrubs, and forests can be seen only along the rivers. The animal world is richer and a bit similar to that found in the steppe zone: there are many rodents and reptiles, and ungulates roam in nearby areas.
The Sahara is considered the largest desert, and in general this natural zonality is characteristic of 11% of the entire earth's surface, and if you add the Arctic desert to it, then 20%. Deserts are found both in the temperate zone of the Northern Hemisphere, and in the tropics and subtropics.
There is no unambiguous definition of the tropics; geographical zones are distinguished: tropical, subequatorial and equatorial, where there are forests similar in composition, but having certain differences.
All forests are divided into savannahs, forest subtropics, and their common feature is that the trees are always green, and these zones differ in the duration of dry and rainy periods. In the savannas, the rainy period lasts 8-9 months. Forest subtropics are characteristic of the eastern outskirts of the continents, where there is a change in the dry period of winter and wet summer with monsoon rains. Tropical forests are characterized by a high degree of moisture, and precipitation can exceed 2000 mm per year.
Latitudinal zoning
Latitudinal (geographical, landscape) zonality refers to a regular change in physical and geographical processes, components and complexes (geosystems) from the equator to the poles.
Belt distribution of solar heat on the earth's surface determines the uneven heating (and density) of atmospheric air. The lower layers of the atmosphere (troposphere) in the tropics warms up strongly from the underlying surface, and weakly in subpolar latitudes. Therefore, above the poles (up to a height of 4 km) there are areas with increased pressure, and near the equator (up to 8-10 km) there is a warm ring with low pressure. With the exception of subpolar and equatorial latitudes, the western transport of air prevails throughout the rest of the space.
The most important consequences of the uneven latitudinal distribution of heat are the zonality of air masses, atmospheric circulation and moisture circulation. Under the influence of uneven heating, as well as evaporation from the underlying surface, air masses are formed that differ in their temperature properties, moisture content and density.
There are four main zonal types of air masses:
1. Equatorial (warm and humid);
2. Tropical (warm and dry);
3. Boreal, or masses of temperate latitudes (cool and humid);
4. Arctic, and in the southern hemisphere Antarctic (cold and relatively dry).
Unequal heating and, as a result, different density of air masses (different atmospheric pressure) cause violation of thermodynamic equilibrium in the troposphere and movement (circulation) of air masses.
As a result of the deflecting action of the Earth's rotation, several circulation zones are formed in the troposphere. The main ones correspond to four zonal types of air masses, so there are four of them in each hemisphere:
1. Equatorial zone, common for the northern and southern hemispheres (low pressure, calm, ascending air currents);
2. Tropical (high pressure, east winds);
3. Moderate (low pressure, westerly winds);
4. Polar (low pressure, easterly winds).
In addition, there are three transition zones:
1. Subarctic;
2. Subtropical;
3. Subequatorial.
In transitional zones, the types of circulation and air masses change seasonally.
The zonality of moisture circulation and humidification is closely related to the zonality of atmospheric circulation. This is clearly manifested in the distribution of precipitation. The zonality of precipitation distribution has its own specifics, a kind of rhythm: three maxima (the main one is at the equator and two minor ones in temperate latitudes) and four minima (in polar and tropical latitudes).
The amount of precipitation in itself does not determine the conditions of moistening or moisture supply for natural processes and the landscape as a whole. In the steppe zone, with 500 mm of annual precipitation, we are talking about insufficient moisture, and in the tundra, at 400 mm, we are talking about excess moisture. To judge moisture, one must know not only the amount of moisture that annually enters the geosystem, but also the amount that is necessary for its optimal functioning. The best indicator of moisture demand is evapotranspiration, i.e., the amount of water that can evaporate from the earth's surface under given climatic conditions, assuming that moisture reserves are not limited. Evaporation is a theoretical value. It should be distinguished from evaporation, i.e., actually evaporating moisture, the value of which is limited by the amount of precipitation. On land, evaporation is always less than evaporation.
The ratio of annual precipitation to annual evaporation can serve as an indicator of climatic humidification. This indicator was first introduced by G. N. Vysotsky. Back in 1905, he used it to characterize the natural zones of European Russia. Subsequently, N. N. Ivanov constructed isolines of this ratio, which they called the moisture coefficient (K). The boundaries of landscape zones coincide with certain K values: in the taiga and tundra it exceeds 1, in the forest-steppe it is 1.0-0.6, in the steppe it is 0.6-0.3, in the semi-desert 0.3-0.12, in the desert it is less than 0.12.
Zoning is expressed not only in the average annual amount of heat and moisture, but also in their regime, i.e., in intra-annual changes. It is well known that the equatorial zone is characterized by the most even temperature regime, four thermal seasons are typical for temperate latitudes, etc. The zonal types of precipitation regime are diverse: in the equatorial zone, precipitation falls more or less evenly, but with two maxima; in subequatorial latitudes, summer is pronounced maximum, in the Mediterranean zone - a winter maximum, for temperate latitudes a uniform distribution with a summer maximum is characteristic, etc.
Climatic zoning is reflected in all other geographical phenomena - in the processes of runoff and the hydrological regime, in the processes of waterlogging and the formation of groundwater, the formation of a weathering crust and soils, in the migration of chemical elements, in the organic world. The zonality is clearly manifested in the surface layer of the ocean (Isachenko, 1991).
Latitudinal zonality is not consistent everywhere - only Russia, Canada and S. Africa.
Provinciality
Provinciality is called changes in the landscape within the geographical zone when moving from the outskirts of the mainland to its interior. The provinciality is based on longitudinal and climatic differences, as a result of atmospheric circulation. Longitudinal and climatic differences, interacting with the geological and geomorphological features of the territory, are reflected in soils, vegetation and other components of the landscape. The oak forest-steppe of the Russian Plain and the birch forest-steppe of the West Siberian Lowland are expressions of provincial changes in the same forest-steppe type of landscape. The same expression of the provincial differences of the forest-steppe type of landscape is the Central Russian Upland, dissected by ravines, and the flat Oka-Don Plain dotted with aspen bushes. In the system of taxonomic units, provinciality is best revealed through physiographic countries and physiographic provinces.
Sector
Geographic sector - a longitude segment of a geographical zone, the originality of the nature of which is determined by longitude-climatic and geological-orographic intrabelt differences.
The landscape-geographic consequences of the continental-ocean circulation of air masses are extremely diverse. It was noted that as the distance from the ocean coasts goes deeper into the continents, there is a regular change in plant communities, animal populations, and soil types. The term sector has now been adopted. Sectorization is the same universal geographical regularity as zoning. There is some analogy between them. However, if both heat supply and humidification play an important role in the latitudinal-zonal change of natural phenomena, then humidification is the main sector factor. The heat reserves change in longitude not so significantly, although these changes also play a certain role in the differentiation of physical and geographical processes.
Physical-geographical sectors are large regional units that extend in a direction close to the meridional and replace each other in longitude. Thus, in Eurasia, there are up to seven sectors: humid Atlantic, Moderately continental East European, sharply continental East Siberian-Central Asian, Monsoonal Pacific Ocean and three others (mainly transitional). In each sector, zoning acquires its own specifics. In the oceanic sectors, zonal contrasts are smoothed out; they are characterized by a forest spectrum of latitudinal zones from taiga to equatorial forests. The continental range of zones is characterized by the predominant development of deserts, semi-deserts, and steppes. The taiga has special features: permafrost, the dominance of light coniferous larch forests, the absence of podzolic soils, etc.
