Latitudinal zonation

Regional and local differentiation of the epigeosphere

Latitudinal zonation

The differentiation of the epigeosphere into geosystems of different orders is determined by the unequal conditions of its development in different parts. As already noted, there are two main levels of physical-geographical differentiation - regional and local (or topological), which are based on deeply different reasons.

Regional differentiation is determined by the relationship between the two main energy factors external to the epigeosphere -radiant energy Sun and internal energy Earth. Both factors manifest themselves unevenly both in space and time. Specific manifestations of both in the nature of the epigeosphere and determine the two most common geographical patterns - zoning And azonality.

Under latitudinal (geographical, landscape)zonality 1

implied natural change in physical-geographical processes, components and complexes (geosystems) from the equator To poles. The primary cause of zonality is the uneven distribution of short-wave radiation from the Sun over latitude due to the sphericity of the Earth and changes in the angle of incidence of solar rays on the earth's surface. For this reason, the amount of radiant energy from the Sun varies per unit area depending on latitude. Consequently, for the existence of zonality, two conditions are sufficient - the flow of solar radiation and the sphericity of the Earth, and theoretically the distribution of this flow over earth's surface should look like a mathematically correct curve (Fig. 5, Ra). In reality, however, the latitudinal distribution of solar energy also depends on some other factors, which also have an external, astronomical nature. One of them is the distance between the Earth and the Sun.

As you move away from the Sun, the flow of its rays becomes weaker, and you can imagine a distance (for example, how far away the planet Pluto is from the Sun) at which the difference

1Further on we will simply call this pattern zonality.

Rice. 5. Zonal distribution of solar radiation:

Ra - radiation at the upper boundary of the atmosphere; total radiation: Rcc- on. land surface, Rco- on the surface of the World Ocean, Rcз- average for the surface globe; radiation balance: Rc- on the land surface, Ro- on the surface of the ocean, Rз - average for the surface of the globe

between the equatorial and polar latitudes, in relation to insolation, it loses its significance - it will be equally cold everywhere (on the surface of Pluto, the estimated temperature is about - 230 ° C). If we were too close to the Sun, on the contrary, all parts of the planet would be excessively hot. In both extreme cases, the existence of neither water in the liquid phase nor life is possible. The Earth turned out to be the most “successfully” located planet in relation to the Sun.

The mass of the Earth also affects the nature of zonation, although

valid: it allows our planet (unlike, for example, the “light” Moon) to retain an atmosphere that serves important factor transformation and redistribution of solar energy.

Significant role plays tilt earth's axis to the ecliptic plane (at an angle of about 66.5°), the uneven supply of solar radiation over the seasons depends on this, which greatly complicates the zonal distribution of heat, and

also moisture 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 throughout the year solar heat and on Earth there would be practically no seasonal change phenomena.

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, also introduces additional complications into the zonation scheme.

If the earth's surface were composed of any one substance and did not have irregularities, the distribution of solar radiation would remain strictly zonal, i.e., despite the complicating influence of the listed astronomical factors, its amount would vary strictly along latitude and at one parallel would be the same. But the heterogeneity of the surface of the globe - the presence of continents and oceans, the diversity of relief and rocks etc. - causes a violation of the mathematically regular distribution of solar energy flow. Since solar energy serves as practically the only source of physical, chemical and biological processes on the earth's surface, these processes must inevitably have a zonal character. The mechanism of geographic zonation is very complex; it manifests itself far from unambiguously in different “environments”, in various components, processes, as well as in different parts of the epigeosphere. The first direct result of the zonal distribution of the solar radiant energy is the zonality of the radiation balance of the earth's surface. However, already in the distribution of incoming radiation we

We observe a clear violation of strict correspondence with latitude. In Fig. 51it is clearly seen that the maximum arriving at the earth's surface total radiation is not observed at the equator, which would be expected theoretically,

and in the space between the 20th and 30th parallels in both hemispheres -

northern and southern. The reason for this phenomenon is that at these latitudes the atmosphere is most transparent to the sun's rays (above the equator there are many clouds in the atmosphere that reflect the sun's rays).

1B SI energy is measured in joules, but until recently it was customary to measure thermal energy in calories. Since in many published geographical works the indicators of radiation and thermal regimes are expressed in calories (or kilocalories), we present the following ratios: 1 J = 0.239 cal; 1 kcal = 4.1868*103J; 1 kcal/cm2= 41.868

rays, scatter and partially absorb them). Over land, the contrasts in atmospheric transparency are especially significant, which is clearly reflected in the shape of the corresponding curve. Thus, the epigeosphere does not passively, automatically respond to the influx of solar energy, but redistributes it in its own way. The curves of the latitudinal distribution of the radiation balance are somewhat smoother, but they are not a simple copy of the theoretical graph of the distribution of the flux of solar rays. These curves are not strictly symmetrical; It is clearly visible that the surface of the oceans is characterized by more high numbers than land. This also talks about active reaction substances of the epigeosphere on external energy influences (in particular, due to the high reflectivity of land, it loses significantly more radiant energy from the Sun than the ocean).

Radiant energy received by the earth's surface from the Sun and converted into heat is spent mainly on evaporation and heat transfer to the atmosphere, and the magnitude of these expenditure items is

radiation balance and their ratios change quite complexly according to

latitude And here we do not observe curves that are strictly symmetrical for land and

ocean (Fig. 6).

The most important consequences of uneven latitudinal heat distribution are

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: equatorial (warm and humid), tropical (warm and dry), boreal or temperate masses (cool and wet), and Arctic, and in the southern hemisphere, Antarctic (cold and relatively dry). Uneven heating and as a result different densities air masses (various Atmosphere pressure) cause a violation of thermodynamic equilibrium in the troposphere and the movement (circulation) of air masses.

If the Earth did not rotate around its axis, air flows in the atmosphere would have a very simple character: from the heated equatorial latitudes, the air would rise up and spread to the poles, and from there it would return to the equator in the surface layers of the troposphere. In other words, the circulation should have had a meridional character and northern winds would constantly blow near the earth's surface in the northern hemisphere, and southern winds in the southern hemisphere. But the deflecting effect of the Earth's rotation introduces significant amendments to this scheme. As a result, several circulation zones are formed in the troposphere (Fig. 7). The main ones correspond to four zonal types of air masses, so in each hemisphere there are four of them: equatorial, common for the northern and southern hemispheres (low pressure, calms, rising air currents), tropical ( high pressure, easterly winds), moderate

Rice. 6. Zonal distribution of radiation balance elements:

1 - the entire surface of the globe, 2 - land, 3 - ocean; LE- heat costs for

evaporation, R - turbulent heat transfer to the atmosphere

(low pressure, westerly winds) and polar (low pressure, eastern winds). In addition, there are three transition zones - subarctic, subtropical and subequatorial, in which the types of circulation and air masses change seasonally due to the fact that in summer (for the corresponding hemisphere) the entire atmospheric circulation system shifts to its “own” pole, and in winter - To equator (and opposite pole). Thus, seven circulation zones can be distinguished in each hemisphere.

Atmospheric circulation is a powerful mechanism for the redistribution of heat and moisture. Thanks to it, zonal temperature differences on the earth's surface are smoothed out, although the maximum still occurs not at the equator, but at slightly higher latitudes of the northern hemisphere (Fig. 8), which is especially clearly expressed on the land surface (Fig. 9).

The zonality of solar heat distribution has found its expression

Rice. 7. Scheme general circulation atmosphere:

tion in the traditional concept of the Earth's thermal belts. However, the continuous nature of changes in air temperature near the earth's surface does not allow us to establish a clear system of zones and justify the criteria for their delimitation. Usually the following zones are distinguished: hot (with an average annual temperature above 20 ° C), two moderate (between the annual isotherm of 20 ° C and the isotherm of the warm month 10°С) and two cold ones (with the temperature of the warmest month below 10°); inside the latter, “regions of eternal frost” are sometimes distinguished (with the temperature of the warmest month below 0 ° C). This scheme, like some of its variants, is purely conventional in nature, and its landscape significance is small due to its extreme schematism. Thus, the temperate zone covers a huge temperature range, which fits the entire winter of landscape zones - from tundra to desert. Note that such temperature zones do not coincide with circulation ones,

The zonality of atmospheric circulation is closely related to the zonality of moisture circulation and humidification. This is clearly manifested in the distribution of precipitation (Fig. 10). Zoning distribution

Rice. 8. Zonal distribution of air temperature on the surface of the globe: I- January, VII - July

Rice. 9. Zonal distribution of heat in the mind -

Renno continental sector of the northern hemisphere:

t- average air temperature in July,

sum of temperatures for a period with average daily

with temperatures above 10° C

The precipitation pattern has its own specificity, a peculiar rhythm: three maxima (the main one 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 moisture or moisture availability 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, with 400 mm, we are talking about excess moisture. To judge moisture, you need to know not only the amount of moisture entering the geosystem annually, but also the amount that is necessary for its optimal functioning. The best indicator of moisture requirements is volatility, i.e., the amount of water that can evaporate from the earth's surface under given climatic conditions, assuming that moisture reserves are unlimited. Volatility is a theoretical value. Her

Rice. 10. Zonal distribution of precipitation, evaporation and coefficient

moisture content on the land surface:

1 - average annual precipitation, 2 - average annual evaporation, 3 - excess of precipitation over evaporation,

4 - excess of evaporation over precipitation, 5 - humidification coefficient (according to Vysotsky - Ivanov)

should be distinguished from evaporation, i.e., actually evaporating moisture, the amount of which is limited by the amount of precipitation. On land, evaporation is always less than evaporation.

In Fig. 10 it is clear that latitudinal changes in precipitation and evaporation do not coincide with each other and, to a large extent, even have opposite character. Ratio of annual precipitation to

annual evaporation value can serve as an indicator of climatic

hydration. This indicator was first introduced by G. N. Vysotsky. Back in 1905, he used it to characterize the natural zones of European Russia. Subsequently, the Leningrad climatologist N.N. Ivanov built isolines of this relationship, which he called humidification coefficient(K), for the entire landmass of the Earth and showed that the boundaries of landscape zones coincide with certain values K: in the taiga and tundra it exceeds 1, in the forest-steppe it is equal

1.0-0.6, in the steppe - 0.6 - 0.3, in the semi-desert - 0.3 - 0.12, in the desert -

less than 0.12 1.

In Fig. Figure 10 schematically shows the change in average values ​​of the humidification coefficient (on land) by latitude. There are four on the curve critical points, where K passes through 1. A value equal to 1 means that moistening conditions are optimal: precipitation can (theoretically) completely evaporate, having done useful “work”; if their

“pass” through plants, they will ensure maximum biomass production. It is no coincidence that in those zones of the Earth where K is close to 1, the highest productivity of vegetation is observed. The excess of precipitation over evaporation (K > 1) means that the moisture is excessive: the precipitation cannot completely return to the atmosphere, it flows along the earth's surface, fills depressions, and causes waterlogging. If precipitation is less than evaporation (K< 1), увлажнение недостаточное; в этих условиях обычно отсутствует лесная растительность, биологическая продуктивность низка, резко падает величина стока,.в почвах развивается засоление.

It should be noted that the amount of evaporation is determined primarily by heat reserves (as well as air humidity, which, in turn, also depends on thermal conditions). Therefore, the ratio of precipitation to evaporation can to a certain extent be considered as an indicator of the ratio of heat and moisture, or the conditions of heat and water supply natural complex(geosystems). There are, however, other ways of expressing the relationships between heat and moisture. The best known is the dryness index proposed by M. I. Budyko and A. A. Grigoriev: R/Lr, where R is the annual radiation balance, L

- latent heat of vaporization, r- annual amount of precipitation. Thus, this index expresses the ratio of the “useful reserve” of radiative heat to the amount of heat that must be expended to evaporate all precipitation in a given place.

By physical meaning The radiation dryness index is close to the Vysotsky-Ivanov humidification coefficient. If in the expression R/Lr divide the numerator and denominator by L, then we will get nothing more than

ratio of the maximum possible under given radiation conditions

evaporation (evaporation rate) to the annual amount of precipitation, i.e., a kind of inverted Vysotsky-Ivanov coefficient - a value close to 1/K. True, an exact match is not possible, since R/L does not fully correspond to evaporation, and for some other reasons related to the peculiarities of the calculations of both indicators. In any case, the dryness index isolines are also in general outline coincide with the boundaries of landscape zones, but in excessively wet zones the index value is less than 1, and in arid zones it is more than 1.

1See: Ivanov N. N. Landscape and climatic zones of the globe // Notes

Geogr. Society of the USSR. New series. T. 1. 1948.

The intensity of many other physical-geographical processes depends on the ratio of heat and moisture. However, zonal changes in heat and moisture have different directions. If heat reserves generally increase from the poles to the equator (although the maximum is somewhat shifted from the equator to tropical latitudes), then the humidification changes as if rhythmically, forming “waves” on the latitudinal curve (see Fig. 10). As the most primary scheme, we can outline several main climatic zones according to the ratio of heat supply and moisture: cold humid (north and south of 50°), warm (hot) dry (between 50° and 10°) and hot humid (between 10° N and 10° S). ).

Zoning is expressed not only in the average annual amount of heat and moisture, but also in their regime, that is, 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. Diverse zonal types precipitation regime: in the equatorial zone precipitation falls more or less evenly, but with two maximums, in subequatorial latitudes the summer maximum is pronounced, in the Mediterranean zone there is a winter maximum, in temperate latitudes a uniform distribution with a summer maximum is characteristic, etc. Climatic zoning is found reflected in all other geographical phenomena - in the processes of runoff and hydrological regime, in the processes of swamping and the formation of groundwater, the formation of weathering crust and soils, in migration chemical elements, in the organic world. Zoning is clearly evident in the surface layer of the ocean (Table 1). Geographical zoning finds vivid expression in the organic world. It is no coincidence that landscape zones got their names for the most part according to characteristic types of vegetation. Zoning is no less expressive soil cover, which served V.V. Dokuchaev as a starting point for developing the doctrine of natural zones, for defining zonality as

"world law".

Sometimes there are also statements that zonality does not appear in the relief of the earth’s surface and the geological foundation of the landscape, and these components are called “azonal”. Divide geographical components into

“zonal” and “azonal” are incorrect, because in any of them, as we will see later, both zonal and azonal features are combined (we are not yet touching on the latter). Relief is no exception in this regard. As is known, it is formed under the influence of so-called endogenous factors, which are typically azonal in nature, and exogenous, associated with the direct or indirect participation of solar energy (weathering, the activity of glaciers, wind, flowing waters, etc.). All processes of the second group are zonal in nature, and the relief forms they create, called sculptural

I can show you with an example what it is latitudinal zonation, because nothing is simpler! As far as I remember, we all should have covered this topic in the 7th or certainly in the 8th grade during a geography lesson. It's never too late to revive memories, and you'll see for yourself how easy it is!

The simplest example of latitudinal zoning

Last May, I was in Barnaul with a friend, and we noticed birch trees with young leaves. And in general there was a lot of green vegetation around. When did we return to Pankrushikha ( Altai region), we saw that the birch trees in this village had just begun to bloom! But Pankrushikha is only about 300 km away from Barnaul.

Having made simple calculations, we found out that our village is only 53.5 km north of Barnaul, but the difference in the speed of vegetation can be seen even with the naked eye! It would seem that such a small distance between settlements, but the lag in leaf growth is approximately 2 weeks.

The sun and latitudinal zonality

Our globe has latitude and longitude - that’s what scientists have agreed upon. On different latitudes heat is distributed unevenly, this leads to the formation of natural zones that differ in the following:

• climate;
• diversity of animals and plants;
• humidity and other factors.

It is easy to understand what wide zoning is if you take into account 2 facts. The Earth is a sphere, and therefore the sun's rays cannot illuminate its surface evenly. Closer to north pole the angle of incidence of the rays becomes so small that one can observe permafrost.

Zoning of the underwater world

Few people know about this, but zonation is also present in the ocean. At a depth of approximately two kilometers, scientists were able to record changes in natural zones, but the ideal depth for study is no more than 150 m. Changes in zones are manifested in the degree of salinity of water, temperature fluctuations, and the variety of marine fish and other organic creatures. Interestingly, the belts in the ocean are not much different from those on the surface of the Earth!

Latitudinal zonality and altitudinal zonality – geographical concepts , characterizing a change in natural conditions, and, as a consequence, a change in natural landscape zones, as one moves from the equator to the poles (latitudinal zonality), or as one rises above sea level.

Latitudinal zonation

It is known that the climate in different parts of our planet is not the same. The most noticeable change in climatic conditions occurs when moving from the equator to the poles: The higher the latitude, the colder the weather becomes. This geographical phenomenon is called latitudinal zoning. It is associated with the uneven distribution of thermal energy from the Sun over the surface of our planet.

Plays a major role in climate change tilt of the earth's axis in relation to the Sun. In addition, latitudinal zonality is associated with different distances of the equatorial and polar parts of the planet from the Sun. However, this factor influences the temperature difference at different latitudes to a much lesser extent than the axis tilt. The Earth's axis of rotation, as is known, is located at a certain angle relative to the ecliptic (the plane of motion of the Sun).

This tilt of the Earth's surface leads to the fact that the sun's rays fall at right angles on the central, equatorial part of the planet. Therefore, it is the equatorial belt that receives maximum solar energy. The closer to the poles, the less the sun's rays warm the earth's surface due to the greater angle of incidence. The higher the latitude, the greater the angle of incidence of the rays, and the more of them are reflected from the surface. They seem to glide along the ground, ricocheting further into outer space.

It should be taken into account that the tilt of the earth's axis relative to the Sun changes throughout the year. This feature is associated with the alternation of seasons: when it is summer in the southern hemisphere, it is winter in the northern hemisphere, and vice versa.

But these seasonal variations do not play a special role in the average annual temperature. Anyway, average temperatures in the equatorial or tropical zone will be positive, and in the region of the poles – negative. Latitudinal zoning has direct influence on climate, landscape, fauna, hydrology and so on. When moving towards the poles, a change latitudinal zones clearly visible not only on land, but also in the ocean.

In geography, as we move towards the poles, the following latitudinal zones are distinguished:

• Equatorial.
• Tropical.
• Subtropical.
• Moderate.
• Subarctic.
• Arctic (polar).

Altitudinal zone

Altitudinal zonation, just like latitudinal zonation, is characterized by changing climatic conditions. Only this change occurs not when moving from the equator to the poles, but from sea level to the highlands. The main differences between lowland and mountainous areas are the difference in temperature.

So, when rising by a kilometer relative to sea level, average annual temperature decreases by approximately 6 degrees. In addition, atmospheric pressure decreases, solar radiation becomes more intense, and the air becomes more rarefied, cleaner and less saturated oxygen.

When reaching a height of several kilometers (2-4 km), air humidity increases and the amount of precipitation increases. Further, as you climb the mountains, the change in natural zones becomes more noticeable. To some extent, such a change is similar to the change in landscape during latitudinal zone. The amount of solar heat loss increases as altitude increases. The reason for this is the lower density of air, which plays the role of a kind of blanket that blocks the sun's rays reflected from the earth and water.

At the same time, the change in altitudinal zones does not always occur in a strictly defined sequence. This change may occur differently in different geographic areas. In tropical or arctic regions, the full cycle of changes in altitudinal zones may not be observed at all. For example, in the mountains of Antarctica or the Arctic region there are no forest belts or alpine meadows. And in many mountains located in the tropics there is a snow-glacier (nival) belt. The most complete change of cycles can be observed in the highest mountain ranges on the equator and in the tropics - in the Himalayas, Tibet, the Andes, and the Cordillera.

Altitudinal zones are divided into several types, starting from the very top to the bottom:

1. Nival belt. This name comes from the Latin “nivas” - snowy. This is the highest altitude zone, characterized by the presence of eternal snow and glaciers. In the tropics it begins at an altitude of at least 6.5 km, and in the polar zones - directly from sea level.
2. Mountain tundra. It is located between the belt of eternal snow and alpine meadows. In this zone, the average annual temperature is 0-5 degrees. The vegetation is represented by mosses and lichens.
3. Alpine meadows. Located below the mountain tundra, the climate is temperate. Vegetable world represented by creeping shrubs and alpine grasses. They are used in summer transhumance for grazing sheep, goats, yaks and other mountain domestic animals.
4. Subalpine zone. It is characterized by a mixture of alpine meadows with rare mountain forests and shrubs. It is a transition zone between high mountain meadows and forest belt.
5. Mountain forests. The lower belt of mountains, with a predominance of a wide variety of tree landscapes. Trees can be either deciduous or coniferous. In the equatorial-tropical zone, the bases of the mountains are often covered with evergreen forests - jungles.

Latitudinal zonation– a natural change in physical-geographical processes, components and complexes of geosystems from the equator to the poles. Latitudinal zoning 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 zone– a natural change in natural conditions and landscapes in the mountains as the absolute height increases. Altitudinal zonation is explained by climate change with height: a drop in air temperature with height and an increase in precipitation and atmospheric humidity. Vertical zonation always begins with the horizontal zone in which the mountainous country is located. Above the belt, they change generally in the same way as the horizontal zones, up to the region of polar snows. Sometimes the less accurate name “vertical zonality” is used. It is inaccurate because the belts have a horizontal rather than vertical extension and replace each other in height (Figure 12).

Figure 12 – Altitudinal zones in the mountains

Natural areas – these are natural-territorial complexes within geographical zones of land, corresponding to types of vegetation. In the distribution of natural zones in the belt, relief, its pattern and absolute altitudes– mountain barriers that block the path of 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 high precipitation throughout the year (more than 3000 mm). Most widespread The zone is located in South America, where it occupies the Amazon basin. In Africa it is located in the Congo Basin, in Asia - on the Malacca 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, and grow on red-yellow ferrallite soils. Forests are different species diversity: abundance of palm trees, lianas and epiphytes; Mangroves are widespread along the sea coasts. There are hundreds of species of trees in such a forest, and they are located in several tiers. Many of them bloom and bear fruit all year round.

The fauna is also diverse. Most of the inhabitants are adapted to life in trees: monkeys, sloths, etc. Land animals include tapirs, hippos, jaguars, and leopards. There are a lot of birds (parrots, hummingbirds), a rich world of reptiles, amphibians and insects.

Savanna and woodland zone located in the subequatorial belt of Africa, Australia, and South America. The climate is characterized by high temperatures and alternating wet and dry seasons. The soils are 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 bushes. 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 American savannas. Adapted to the dry season individual species trees that store moisture or retard evaporation. These are African baobabs, Australian eucalyptus trees, South American bottle tree and palm trees. Rich and varied animal world. main feature fauna of savannas - the abundance of birds, ungulates and the presence of large predators. Vegetation promotes the spread of large herbivores and predatory mammals, birds, reptiles, and insects.

Zone variable-humid deciduous forests from the east, north and south it is framed by the hylaia. Here, both evergreen rigid-leaved species characteristic of the Giles and species that partially shed their foliage in summer are common; Lateritic red and yellow soils are formed. The fauna is rich and diverse.

Natural zones of tropical and subtropical latitudes. In the tropical zone of the North and Southern hemispheres prevails tropical desert zone. The climate is tropical desert, hot and dry, therefore the soils are underdeveloped and often saline. Vegetation on such soils is sparse: rare tough grasses, thorny bushes, saltworts, and lichens. The animal world is richer than the plant world, since reptiles (snakes, lizards) and insects are capable of long time be without water. Mammals include ungulates (the 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.

In the tropical zone it is also represented zone of humid and variable-humid tropical forests. It formed in the eastern part of South America, in the northern and northeastern parts of Australia. The climate is humid with consistently high temperatures and high amounts of rainfall that occur during the summer monsoons. Variably moist, evergreen forests grow on red-yellow and red soils, rich in species composition (palm trees, ficus trees). They are similar to equatorial forests. The fauna is rich and diverse (monkeys, parrots).

Subtropical hard-leaved evergreen forests and shrubs characteristic of the western part of the continents, where the climate is Mediterranean: hot and dry summers, warm and rainy winters. Brown soils have high fertility and are used for cultivating valuable subtropical crops. The lack of moisture during periods of intense solar radiation led to the appearance of adaptations in plants in the form of hard leaves with a waxy coating that reduce evaporation. Hard-leaved evergreen forests are decorated 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.

Subtropical rainforest zone located in the east of the continents, where the climate is subtropical monsoon. Precipitation occurs in summer. The forests are dense, evergreen, broad-leaved and mixed, growing on red soils and yellow soils. The fauna is diverse, there are bears, deer, and roe deer.

Zones of subtropical steppes, semi-deserts and deserts distributed in sectors in the interior of continents. In South America the steppes are called pampas. Subtropical dry with hot summers and relatively warm winter The climate allows drought-resistant grasses and grains (wormwood, feather grass) to grow on gray-brown steppe and brown desert soils. The fauna is distinguished by species diversity. Typical mammals are ground squirrels, jerboas, goitered gazelles, kulans, jackals and hyenas. Lizards and snakes are numerous.

Natural areas of temperate latitudes include zones of deserts and semi-deserts, steppes, forest-steppes, and forests.

Deserts and semi-deserts temperate latitudes occupy large areas in the interior of Eurasia and North America, and 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; in depressions on saline soils - solyanka. The fauna is dominated by lizards, snakes, turtles, jerboas, and saigas are common.

Steppes occupy large areas in Eurasia, South and North America. In North America they are called prairies. The climate of the steppes is continental, arid. Due to lack of moisture, there are no trees and a rich grass cover (feather grass, fescue and other grasses). The most fertile soils, chernozem soils, are formed in the steppes. In summer the vegetation in the steppes is sparse, but in the short spring many flowers bloom; lilies, tulips, poppies. The fauna of the steppes is represented mainly by mice, gophers, hamsters, as well as foxes and ferrets. The nature of the steppes has changed in many ways under the influence of man.

To the north of the steppes there is a zone forest-steppes. This is a transition zone, with areas of forest interspersed with significant areas covered with herbaceous vegetation.

Broad-leaved and mixed forest zones presented in Eurasia, North and South America. The climate, when moving from the oceans into the continents, changes from marine (monsoon) to continental. Vegetation changes depending on the climate. The zone of broad-leaved forests (beech, oak, maple, linden) turns into a zone of mixed forests (pine, spruce, oak, hornbeam, etc.). To the north and further into 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 - sod-podzolic, in the taiga - 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 the open forest (low larches, spruce, birch) gradually turns into tundra. The fauna is represented by inhabitants of the forest and tundra zones (snowy owls, lemmings).

Tundra characterized by treelessness. A climate with long, cold winters and damp and cold summers. This leads to severe freezing of the soil, forming permafrost. Evaporation here is low, organic matter does not have time to decompose, and as a result, swamps are formed. On humus-poor tundra-gley and peat-bog soils of the tundra, mosses, lichens, low grasses, dwarf birch trees, willows, etc. grow. According to the nature of the vegetation of the tundra, there are mosses, lichens, shrubs. The fauna is poor (reindeer, arctic fox, owls, pieds).

Arctic (Antarctic) desert zone located in polar latitudes. Due to the very cold climate with low temperatures throughout the year large areas the land is covered with glaciers. The soils are almost undeveloped. In 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 - the musk ox. Natural conditions in Antarctica they are even more severe. Penguins, petrels, and cormorants nest on the coast. Whales, seals, and fish live in Antarctic waters.

Related information.

Latitudinal zonation- natural changes in physical-geographical processes, components and complexes of geosystems from the equator to the poles.

The primary cause of zonality is the uneven distribution of solar energy across latitude due to spherical Earth and changes in the angle of incidence of sunlight 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 retain the atmosphere, which serves as a transformer and redistributor of energy.

The inclination of the axis to the ecliptic plane is of great importance; the unevenness of the solar heat supply over the seasons depends on this, and daily rotation planets causes the deviation of air masses. The result of differences in the distribution of radiant energy from the Sun is the zonal radiation balance of the earth's surface. The unevenness of heat supply affects the distribution of air masses, moisture circulation and atmospheric circulation.

Zoning is expressed not only in the average annual amount of heat and water, but also in intra-annual configurations. Climatic zonation is reflected in the runoff and hydrological regime, the formation of weathering crust, and waterlogging. A huge impact is exerted on the organic world and special relief forms. The homogeneous composition and high air mobility smooth out zonal differences with height.

There are 7 circulation zones in each hemisphere.

Vertical zonality is also related to the amount of heat, but it only depends on the altitude above sea level. As you climb the mountains, the climate, soil class, vegetation and fauna change. It is curious that even in hot countries it is possible to encounter tundra landscapes and even icy desert. However, in order to see this, you will have to climb high into the mountains. Thus, in the tropical and equatorial zones of the Andes of South America and in the Himalayas, landscapes alternately change from wet rain forests to alpine meadows and a zone of endless glaciers and snow.

It cannot be said that the altitudinal zone completely repeats the latitudinal geographical zones, since many conditions are not repeated in the mountains and plains. The range of altitudinal zones near the equator is more diverse, for example on the highest peaks of Africa, Mount Kilimanjaro, Kenya, Margherita Peak, and in South America on the slopes of the Andes.