The constituent parts of the geographic envelope are called. The structure of the geographic shell
The earth includes several concentric shells. Geographical shell called a special shell of the Earth, where the upper part of the lithosphere, the lower part of the atmosphere and the hydrosphere come into contact and interact, within the boundaries of which living organisms develop. As already noted, of the planets of the solar system, the geographic shell is characteristic only of the Earth.
The exact boundaries of the geographic shell are not precisely defined. It is generally accepted that it extends upwards to the "ozone screen", that is, to a height of 25 km. The hydrosphere enters the geographic shell as a whole, and the lithosphere - only with its upper layers, to a depth of several kilometers. Thus, within its boundaries, the geographic shell almost coincides with the biosphere.
The specific features of the geographic envelope are a wide variety of material composition and types of energy, the presence of life, the existence of human society.
The existence and development of the geographic envelope is associated with a number of patterns, the main of which are integrity, rhythm And zoning.
Integrity of the geographic envelope due to the mutual penetration into each other of its constituent parts. Changing one of them changes the others. An example is the Quaternary glaciations. The cooling of the climate led to the formation of layers of snow and ice that covered the northern parts of Eurasia and North America. As a result of glaciation, new forms of relief arose, soils, vegetation, and wildlife changed.
Manifestation integrity of the geographic envelope is a circulatory system. All shells of the Earth are covered by a large water cycle. In the process of biological cycle, green plants convert the energy of the Sun into the energy of chemical bonds. From inorganic substances ( CO2 And H2O) are formed organic (starch). Animals, not having this ability, use ready-made organic substances by eating plants or other animals. Microorganisms destroy the organic matter of dead plants and animals to simple compounds. Plants will use them again.
The repetition in time of certain natural phenomena is called rhythm. There are rhythms of different duration. The most obvious daily And seasonal rhythm. The daily rhythm is due to the movement of the Earth around its axis, the seasonal rhythm is due to orbital motion. In addition to daily and annual rhythms, there are also longer rhythms, or cycles. So, in the Neogene-Quaternary time, the eras of glaciations and interglacials repeatedly succeeded each other. In the history of the Earth, several cycles of mountain-building processes are distinguished.
Zoning one of the main regularities of geographic 
physical shell. It manifests itself in an ordered pattern of natural components as it moves from the poles to the equator. Zoning is based on the unequal amount of solar heat and light received by different parts of the earth's surface. Many components of nature are subject to zonality: climate, land waters, small landforms formed by the action of external forces, soils, vegetation, wildlife. The manifestations of the external forces of the Earth, the features of the movement and structure of the earth's crust and the associated placement of large landforms do not obey the law of zonality.
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The geographic shell of the earth or the landscape shell, the sphere of interpenetration and interaction of the lithosphere, atmosphere, hydrosphere and biosphere. It is characterized by a complex composition and structure. The vertical thickness of the geographical envelope is tens of kilometers. The integrity of the geographic envelope is determined by the continuous energy and mass exchange between the land and the atmosphere, the World Ocean and organisms. Natural processes in the geographic envelope are carried out due to the radiant energy of the Sun and the internal energy of the Earth. Within the geographic shell, humanity arose and is developing, drawing resources from the shell for its existence and influencing it.
The upper boundary of the Geographical envelope should be drawn along the stratopause, because up to this point, the thermal effect of the earth's surface on atmospheric processes affects. The boundary of the geographic shell in the lithosphere is combined with the lower limit of the hypergenesis region. Sometimes the foot of the stratisphere, the average depth of seismic or volcanic sources, the base of the earth's crust, and the level of zero annual temperature amplitudes are sometimes taken as the lower boundary of the geographic envelope. Thus, the geographical envelope completely covers the hydrosphere, descending in the ocean 10-11 km below the Earth's surface, the upper zone of the earth's crust and the lower part of the atmosphere (a layer 25-30 km thick). The greatest thickness of the geographical envelope is close to 40 km.
The qualitative differences between the geographic shell and other shells of the Earth are as follows. The geographical envelope is formed under the influence of both terrestrial and cosmic processes; it is exceptionally rich in various types of free energy; the substance is present in all states of aggregation; the degree of aggregation of matter is extremely diverse - from free elementary particles - from atoms, ions, molecules to chemical compounds and the most complex biological bodies; the concentration of heat coming from the sun; presence of human society.
The main material components of the geographic envelope are the rocks that form the earth's crust in form - relief), air masses, water accumulations, soil cover and biocenoses; in the polar latitudes and high mountains, the role of ice accumulations is essential.
The main energy components are gravitational energy, the internal heat of the Earth, the radiant energy of the Sun and the energy of cosmic rays. Despite the limited set of components, their combinations can be very diverse; it also depends on the number of terms included in the combination and on their internal variations, since each component is also a very complex natural combination and, most importantly, on the nature of their interaction and relationships, i.e., on the geographical structure.
The geographic envelope has the following important features:
1) the integrity of the geographical shell, due to the continuous exchange of matter and energy between its constituent parts, since the interaction of all components binds them into a single material system, in which a change in even one link entails a conjugate change in all the others.
2) The presence of the circulation of substances and the energy associated with it, which ensures the repetition of the same processes and phenomena and their high overall efficiency with a limited volume of the initial substance involved in these processes. The complexity of the cycles is different: some of them are mechanical movements (atmospheric circulation, a system of sea surface currents), others are accompanied by a change in the aggregate state of matter (water circulation on Earth), thirdly, its chemical transformation also occurs (biological cycle). The cycles, however, are not closed, and the differences between their initial and final stages testify to the development of the system.
3) Rhythm, i.e., the repetition in time of various processes and phenomena. It is due mainly to astronomical and geological reasons. There is a daily rhythm (change of day and night), annual (change of seasons), intra-secular (for example, cycles of 25-50 years, observed in climate fluctuations, glaciers, lake levels, river flow, etc.), super-secular (for example , change for every 1800-1900 years of a phase of a cool-humid climate with a phase of dry and warm), geological (caledonian, hercynian, alpine cycles of 200-240 million years each), etc. Rhythms, like cycles, are not closed: the state that was at the beginning of the rhythm is not repeated at the end.
4). Continuity of development of the geographic shell, as a kind of integral system under the influence of the contradictory interaction of exogenous and endogenous forces. The consequences and features of this development are: a) territorial differentiation of the surface of the land, ocean and seabed into areas that differ in internal features and external appearance (landscapes, geocomplexes); determined by spatial changes in geographic structure; special forms of territorial differentiation—geographical zonality; b) polar asymmetry, that is, significant differences in the nature of the geographical envelope in the northern and southern hemispheres; manifests itself in the distribution of land and sea (the vast majority of land in the Northern Hemisphere), climate, composition of flora and fauna, in the nature of landscape zones, etc.; c) heterochrony or metachronism of the development of the geographic envelope, due to the spatial heterogeneity of the nature of the Earth, as a result of which at the same moment different territories are either in different phases of an equally directed evolutionary process, or differ from each other in the direction of development (examples: ancient glaciation in different regions Earth began and ended at the same time, in some geographical areas the climate becomes drier, in others at the same time - wetter, etc.).
The geographical shell is the subject of study of physical geography.
21.1. The concept of a geographical shell
The geographic shell is an integral continuous near-surface part of the Earth, within which the lithosphere, hydrosphere, atmosphere and living matter come into contact and interact. This is the most complex and diverse material system of our planet. The geographic shell includes the entire hydrosphere, the lower layer of the atmosphere, the upper part of the lithosphere and the biosphere, which are its structural parts.
The geographical shell does not have clear boundaries, so scientists conduct them in different ways. Usually, the ozone screen, located at an altitude of about 25–30 km, is taken as the upper limit, where most of the ultraviolet solar radiation, which has a detrimental effect on living organisms, is retained. At the same time, the main processes that determine the weather and climate, and hence the formation of landscapes, occur in the troposphere, the height of which varies in latitudes from 16–18 km near the equator to 8 km above the poles. The base of the weathering crust is most often considered the lower boundary on land. This part of the earth's surface is subject to the strongest changes under the influence of the atmosphere, hydrosphere and living organisms. Its maximum power is about one kilometer. Thus, the total thickness of the geographic envelope on land is about 30 km. In the ocean, the bottom of the geographic shell is considered to be its bottom.
However, it should be noted that there are the greatest differences among scientists regarding the position of the lower boundary of the geographic envelope. We can give five or six points of view on this issue with appropriate justifications. At the same time, the boundary is drawn at depths from several hundred meters to tens and even hundreds of kilometers, and in different ways within the continents and oceans, as well as various parts of the continents.
There is no unity in regard to the name of the geographic shell. The following terms have been proposed for its designation: landscape shell or sphere, geographic sphere or environment, biogenosphere, epigeosphere, and a number of others. However, at present, most geographers adhere to the names and boundaries of the geographic shell that we have given.
The idea of a geographical shell as a special natural formation was formulated in science in the 20th century. The main merit in the development of this idea belongs to Academician A. A. Grigoriev. He also revealed the main features of the geographical shell, which are as follows:
Compared to the bowels of the Earth and the rest of the atmosphere, the geographic envelope is characterized by a greater variety of material composition, as well as the energy entering non-human forms and the forms of their transformation.
The substance in the geographic envelope is in three states of aggregation (outside it, one state of matter prevails).
All processes here proceed due to both solar and intraterrestrial energy sources (outside the geographic envelope - mainly due to one of them), and solar energy absolutely prevails.
A substance in a geographic envelope has a wide range of physical characteristics (density, thermal conductivity, heat capacity, etc.). Only here is life. The geographical envelope is the arena of human life and activity.
5. The general process that connects the spheres that make up the geographical envelope is the movement of matter and energy, which takes place in the form of cycles of matter and in changes in the components of energy balances. All cycles of matter occur at different speeds and at different levels of substance organization (macro level, micro levels of phase transitions and chemical transformations). Part of the energy entering the geographic shell is conserved in it, the other part in the process of the circulation of substances leaves the planet, having previously experienced a number of transformations.
The geographical envelope consists of components. These are certain material formations: rocks, water, air, plants, animals, soils. Components differ in physical state (solid, liquid, gaseous), level of organization (non-living, living, bio-inert - a combination of living and non-living, which includes the soil), chemical composition, and also by the degree of activity. According to the last criterion, the components are divided into stable (inert) - rocks and soils, mobile - water and air, and active - living matter.
Sometimes partial shells are considered as components of the geographic shell - the lithosphere, atmosphere, hydrosphere and biosphere. This is not a completely correct idea, because not all of the lithosphere and atmosphere are part of the geographic shell, and the biosphere does not form a spatially isolated shell: it is the area of distribution of living matter within a part of other shells.
Geographical shell geographically and in volume almost coincides with the biosphere. However, there is no single point of view regarding the relationship between the biosphere and the geographic envelope. Some scientists believe that the concepts of "biosphere" and "geographical envelope" are very close or even identical. In this regard, proposals were made to replace the term "geographical envelope" with the term "biosphere" as more common and familiar to the general public. Other geographers consider the biosphere as a certain stage in the development of the geographical envelope (three main stages are distinguished in its history: geological, biogenic and modern anthropogenic). According to others, the terms "biosphere" and "geographical shell" are not identical, since the concept of "biosphere" focuses on the active role of living matter in the development of this shell, and this term has a special biocentric orientation. Apparently, one should agree with the latter approach.
The geographical shell is now considered as a system, and the system is complex (consisting of many material bodies), dynamic (continuously changing), self-regulating (having a certain
stable stability) and open (continuously exchanging matter, energy and information with the environment).
The geographic envelope is heterogeneous. It has a tiered vertical structure, consisting of individual spheres. The substance is distributed in it by density: the higher the density of the substance, the lower it is located. At the same time, the geographic shell has the most complex structure at the contact of the spheres: the atmosphere and the lithosphere (the land surface), the atmosphere and the hydrosphere (the surface layers of the World Ocean), the hydrosphere and the lithosphere (the bottom of the World Ocean), as well as in the coastal strip of the ocean, where the hydrosphere is in contact, lithosphere and atmosphere. With distance from these contact zones, the structure of the geographic envelope becomes simpler.
The vertical differentiation of the geographic shell served as the basis for the well-known geographer F.N. Milkov to single out a landscape sphere inside this shell - a thin layer of direct contact and active interaction of the earth's crust, atmosphere and water shell. The landscape sphere is the biological focus of the geographic envelope. Its thickness varies from several tens of meters to 200-300 m. ). The most common of them is water-surface. It includes a 200-meter surface layer of water and a layer of air 50 m high. The composition of the terrestrial version of the landscape sphere, better studied than others, includes a surface layer of air 30–50 m high, vegetation with the animal world inhabiting it, soil and modern weathering crust . Thus, the landscape sphere is the active core of the geographic envelope.
The geographic envelope is heterogeneous not only in the vertical but also in the horizontal direction. In this regard, it is divided into separate natural complexes. The differentiation of the geographic envelope into natural complexes is due to the uneven distribution of heat in its various parts and the heterogeneity of the earth's surface (the presence of continents and oceanic depressions, mountains, plains, elevations, etc.). The largest natural complex is the geographical envelope itself. Geographical complexes also include continents and oceans, natural zones (tundra, forests, steppes, etc.), as well as regional natural formations, such as the East European Plain, the Sahara Desert, the Amazonian Lowland, etc. Small natural complexes are confined to individual hills, their slopes, river valleys and their individual sections (channel, floodplain, floodplain terraces) and other meso- and microforms of relief. The smaller the natural complex, the more homogeneous the natural conditions within it. Thus, the entire geographic envelope has a complex mosaic structure; it consists of natural complexes of different ranks.
The geographical shell has gone through a long and complex history of development, which can be divided into several stages. It is assumed that the primary cold Earth was formed, like other planets, from interstellar dust and gases about 5 billion years ago. In the pregeological period of the Earth's development, which ended 4.5 billion years ago, its accretion took place, the surface was bombarded by meteorites and experienced powerful tidal fluctuations from the nearby Moon. The geographic envelope as a complex of spheres did not exist then.
The first one is the geological stage of the development of the geographic envelope, which began together with the early geological stage of the Earth's development (4.6 billion years ago) and captured its entire pre-Cambrian history, continuing until the beginning of the Phanerozoic (570 million years ago). This was the period of the formation of the hydrosphere and atmosphere during degassing of the mantle. The concentration of heavy elements (iron, nickel) in the center of the Earth and its rapid rotation caused the emergence of a powerful magnetic field around the Earth, protecting the earth's surface from cosmic radiation. Thick strata of the continental crust arose along with the primary oceanic, and by the end of the stage, the continental crust began to split into plates and, together with the resulting young oceanic crust, began to drift through the viscous asthenosphere.
At this stage, 3.6–3.8 billion years ago, the first signs of life appeared in the aquatic environment, which, by the end of the geological stage, conquered the oceanic spaces of the Earth. At that time, organic matter did not yet play an important role in the development of the geographic envelope, as it does now.
The second stage in the development of the geographic envelope (from 570 million to 40 thousand years ago) includes the Paleozoic, Mesozoic, and almost the entire Cenozoic. This stage is characterized by the formation of an ozone screen, the formation of the modern atmosphere and hydrosphere, a sharp qualitative and quantitative leap in the development of the organic world, and the beginning of soil formation. Moreover, as in the previous stage, periods of evolutionary development alternated with periods that had a catastrophic character. This applies to both inorganic and organic nature. Thus, periods of calm evolution of living organisms (homeostasis) were replaced by periods of mass extinction of plants and animals (four such periods were recorded during the stage under consideration).
The third stage (40 thousand years ago - our time) begins with the appearance of modern Homo sapiens, more precisely, with the beginning of a noticeable and ever-increasing impact of man on his natural environment 1 .
In conclusion, it should be said that the development of the geographical shell proceeded along the line of complication of its structure, accompanied by processes and phenomena that were still far from known by man. As one of the geographers successfully noted in this regard, the geographic shell is a single unique object with a mysterious past and an unpredictable future.
21.2. The main regularities of the geographical shell
The geographic envelope has a number of general patterns. These include: integrity, rhythm of development, horizontal zonality, azonality, polar asymmetry.
Integrity is the unity of the geographical shell, due to the close relationship of its constituent components. Moreover, the geographic envelope is not a mechanical sum of components, but a qualitatively new formation that has its own characteristics and develops as a whole. As a result of the interaction of components in natural complexes, the production of living matter is carried out and soil is formed. A change within the natural complex of one of the components leads to a change in the others and the natural complex as a whole.
Many examples can be cited to support this. The most striking of them for the geographic envelope is the example of the appearance of the El Niño current in the equatorial Pacific Ocean.
Usually trade winds blow here and sea currents move from the coast of America to Asia. However, with an interval of 4-7 years, the situation changes. The winds, for unknown reasons, change their direction to the opposite, heading towards the shores of South America. Under their influence, a warm El Niño current arises, pushing the cold waters of the Peruvian Current, rich in plankton, from the coast of the mainland. This current appears off the coast of Ecuador in the band 5 - 7 ° S. sh., washes the coast of Peru and the northern part of Chile, penetrating up to 15 ° S. sh., and sometimes to the south. This usually happens at the end of the year (the name of the current, which usually occurs around Christmas, means “baby” in Spanish and comes from the baby Christ), lasts 12-15 months and is accompanied by catastrophic consequences for South America: heavy rainfall in the form of downpours, floods, the development of mudflows, landslides, erosion, the reproduction of harmful insects, the departure of fish from the coast due to the arrival of warm waters, etc. To date, the dependence of weather conditions in many regions of our planet on the El Niño current has been revealed: unusual heavy rains in Japan, severe droughts in South Africa, droughts and wildfires in Australia, violent floods in England, heavy winter precipitation in the Eastern Mediterranean. Its occurrence also affects the economy of many countries, primarily the production of agricultural crops (coffee, cocoa beans, tea, sugar cane, etc.) and fishing. The most intense in the last century was El Niño in 1982–1983. It is estimated that during this time the current caused the world economy material damage in the amount of about $ 14 billion and led to the death of 20 thousand people.
Other examples of the manifestation of the integrity of the geographic envelope are shown in Scheme 3.
The integrity of the geographic shell is achieved by the circulation of energy and matter. Energy cycles are expressed by balances. For the geographic envelope, radiation and heat balances are most typical. As for the cycles of matter, the matter of all spheres of the geographic envelope is involved in them.
Cycles in the geographic envelope are different in their complexity. Some of them, for example, the circulation of the atmosphere, the system of sea currents or the movement of masses in the bowels of the Earth, are mechanical movements, others (the water cycle) are accompanied by a change in the aggregate state of matter, and others (biological circulation and changes in matter in the lithosphere) are chemical transformations.
As a result of the cycles in the geographic shell, there is an interaction between the private shells, during which they exchange matter and energy. It is sometimes argued that the atmosphere, hydrosphere and lithosphere penetrate each other. In fact, this is not so: it is not the geospheres that penetrate each other, but their components. Thus, solid particles of the lithosphere enter the atmosphere and hydrosphere, air penetrates the lithosphere and hydrosphere, etc. Particles of matter that have fallen from one sphere to another become an integral part of the latter. Water and solid particles of the atmosphere are its constituent parts, just like gases and solid particles in water bodies belong to the hydrosphere. The presence of substances that have fallen from one shell into another form, to one degree or another, the properties of this shell.
A typical example of a cycle that connects all the structural parts of a geographic envelope is the water cycle. The general, global and private cycles are known: ocean - atmosphere, continent - atmosphere, intra-oceanic, intra-atmospheric, intra-terrestrial, etc. All water cycles occur due to the mechanical movement of huge masses of water, but many of them - between different spheres, are accompanied by phase transitions water or occur with the participation of some specific forces, such as surface tension. The global water cycle, covering all spheres, is accompanied, in addition, by the chemical transformations of water - the entry of its molecules into minerals, into organisms. The complete (global) water cycle with all its particular components is well represented in the scheme of L. S. Abramov (Fig. 146). In total, there are 23 cycles of moisture circulation.
Integrity is the most important geographical regularity, on the knowledge of which the theory and practice of rational nature management is based. Accounting for this regularity makes it possible to foresee possible changes in nature, to give a geographical forecast of the results of human impact on nature, to carry out a geographical examination of projects related to the economic development of certain territories.
rice. 146. Complete and partial water cycles in nature
The geographical shell is characterized by the rhythm of development - the repetition in time of certain phenomena. There are two forms of rhythm: periodic and cyclic. Under the periods understand the rhythms of the same duration, under the cycles - a variable duration. In nature, there are rhythms of different duration - daily, intra-secular, centuries-old and super-secular, having different origins. Manifesting at the same time, rhythms are superimposed one on another, in some cases strengthening, in others - weakening each other.
The daily rhythm, due to the rotation of the Earth around its axis, manifests itself in changes in temperature, pressure, air humidity, cloudiness, wind strength, in the phenomena of ebbs and flows, the circulation of breezes, in the functioning of living organisms and in a number of other phenomena. The daily rhythm at different latitudes has its own specifics. This is due to the duration of illumination and the height of the Sun above the horizon.
The annual rhythm is manifested in the change of seasons, in the formation of monsoons, in the change in the intensity of exogenous processes, as well as in the processes of soil formation and destruction of rocks, seasonality in human economic activity. In different natural regions, a different number of seasons is distinguished. So, in the equatorial zone there is only one season of the year - hot and humid, in the savannahs there are two seasons: dry and wet. In temperate latitudes, climatologists even suggest distinguishing six seasons of the year: in addition to the well-known four, two more - pre-winter and pre-spring. Pre-winter is the period from the moment the average daily temperature passes through 0 ° C in autumn until the establishment of a stable snow cover. Prespring begins with the beginning of the melting of the snow cover until its complete disappearance. As can be seen, the annual rhythm is best expressed in the temperate zone and very weakly in the equatorial zone. The seasons of the year in different regions may have different names. It is hardly legitimate to single out the winter season at low latitudes. It should be borne in mind that the reasons for the annual rhythm are different in different natural regions. So, in subpolar latitudes, it is determined by the light regime, in temperate latitudes - by the course of temperatures, in subequatorial latitudes - by the moisture regime.
Of the intrasecular rhythms, the 11-year rhythms associated with changes in solar activity are most clearly expressed. It has a great influence on the Earth's magnetic field and ionosphere and, through them, on many processes in the geographic envelope. This leads to periodic changes in atmospheric processes, in particular, to deepening of cyclones and strengthening of anticyclones, fluctuations in river flow, and changes in the intensity of sedimentation in lakes. The rhythms of solar activity affect the growth of woody plants, which is reflected in the thickness of their growth rings, contribute to periodic outbreaks of epidemic diseases, as well as the mass reproduction of pests of forests and crops, including locusts. As the famous heliobiologist A.L. Chizhevsky, 11-year rhythms affect not only the development of many natural processes, but also the organism of animals and humans, as well as their life and activities. It is interesting to note that some geologists now associate tectonic activity with solar activity. A sensational statement on this subject was made at the International Geological Congress held in 1996 in Beijing. Employees of the Institute of Geology of China revealed the cyclicity of earthquakes in the eastern part of their country. Exactly every 22 years (doubled solar cycle) in this area there is a perturbation of the earth's crust. It is preceded by sunspot activity. Scientists have studied historical chronicles since 1888 and found complete confirmation of their conclusions regarding the 22-year cycles of earth's crust activity leading to earthquakes.
Centuries-old rhythms are manifested only in individual processes and phenomena. Among them, the rhythm lasting 1800–1900 years, established by A.V. Shnitnikov. Three phases are distinguished in it: transgressive (of a cool-humid climate), developing rapidly, but short (300–500 years); regressive (dry and warm climate), developing slowly (600 - 800 years); transitional (700–800 years). In the transgressive phase, glaciation on Earth intensifies, river flow increases, and the level of lakes rises. In the regressive phase, glaciers, on the contrary, retreat, rivers become shallow, and the water level in lakes decreases.
The rhythm under consideration is associated with a change in tide-forming forces. Approximately every 1800 years, the Sun, Moon and Earth are in the same plane and on the same straight line, and the distance between the Earth and the Sun becomes the smallest. Tidal forces reach their maximum value. In the World Ocean, the movement of water in the vertical direction increases to a maximum - deep cold waters come to the surface, which leads to cooling of the atmosphere and the formation of a transgressive phase. Over time, the “parade of the Moon, Earth and Sun” is disturbed and humidity returns to normal.
The supersecular cycles include three cycles associated with changes in the orbital characteristics of the Earth: precession (26 thousand years), a complete oscillation of the ecliptic plane relative to the earth's axis (42 thousand years), a complete change in the eccentricity of the orbit (92 - 94 thousand years).
The longest cycles in the development of our planet are tectonic cycles lasting about 200 million years, known to us as the Baikal, Caledonian, Hercynian and Mesozoic-Alpine epochs of folding. They are caused by cosmic causes, mainly by the onset of galactic summer in a galactic year. The galactic year is understood as the revolution of the solar system around the center of the galaxy, lasting the same number of years. When the system approaches the center of the Galaxy, in perigalactia, i.e., "galactic summer", gravity increases by 27% compared to apogalactia, which leads to an increase in tectonic activity on Earth.
There are also reversals of the Earth's magnetic field with a duration of 145–160 Ma.
Rhythmic phenomena do not completely repeat at the end of the rhythm the state of nature that was at its beginning. This is precisely what explains the directed development of natural processes, which, when rhythm is superimposed on progress, ultimately turns out to be going in a spiral.
The study of rhythmic phenomena is of great importance for the development of geographic forecasts.
The planetary geographical regularity, established by the great Russian scientist V.V. Dokuchaev, is zoning - a regular change in natural components and natural complexes in the direction from the equator to the poles. Zoning is due to the unequal amount of heat coming to different latitudes due to the spherical shape of the Earth. The distance of the Earth from the Sun is also important. The dimensions of the Earth are also important: its mass allows it to keep an air shell around it, without which there would be no zoning. Finally, zoning is complicated by a certain inclination of the earth's axis to the plane of the ecliptic.
On Earth, the climate, land and ocean waters, weathering processes, some landforms formed under the influence of external forces (surface waters, winds, glaciers), vegetation, soils, and wildlife are zonal. The zonality of components and structural parts predetermines the zonality of the entire geographic envelope, i.e., geographic or landscape zonality. Geographers distinguish between component (climate, vegetation, soil, etc.) and complex (geographical or landscape) zonality. The concept of component zoning has developed since ancient times. Complex zoning was discovered by V.V. Dokuchaev.
The largest zonal subdivisions of the geographic shell are geographic belts. They differ from each other in temperature conditions, general features of the circulation of the atmosphere. On land, the following geographical zones are distinguished: equatorial and in each hemisphere - subequatorial, tropical, subtropical, temperate, as well as in the northern hemisphere - subarctic and arctic, and in the southern - subantarctic and antarctic. In total, thus, 13 natural belts are distinguished on land. Each of them has its own characteristics for human life and economic activity. These conditions are most favorable in three zones: subtropical, temperate and subequatorial (by the way, all three have a well-defined seasonal rhythm of nature development). They are more intensively mastered by man than others.
Belts similar in name (with the exception of subequatorial ones) have also been identified in the World Ocean. The zonality of the World Ocean is expressed in sublatitudinal changes in temperature, salinity, density, gas composition of water, in the dynamics of the upper water column, as well as in the organic world. D.V. Bogdanov distinguishes natural oceanic belts - "vast water spaces covering the surface of the ocean and the adjacent upper layers to a depth of several hundred meters, in which the features of the nature of the oceans (temperature and salinity of water, currents, ice conditions, biological and some hydrochemical indicators) are clearly visible, directly or indirectly due to the influence of the latitude of the place ”(Fig. 147). The boundaries of the belts were drawn by him along oceanological fronts - the boundaries of the distribution and interaction of waters with different properties. Oceanic belts are very well combined with physical and geographical zones on land; the exception is the subequatorial belt of land, which does not have its own oceanic counterpart.
Within the belts on land, according to the ratio of heat and moisture, natural zones are distinguished, the names of which are determined by the type of vegetation prevailing in them. So, for example, in the subarctic zone there are zones of tundra and forest-tundra, in the temperate zone there are zones of forests, forest-steppes, steppes, semi-deserts and deserts, in the tropical zone there are zones of evergreen forests, semi-deserts and deserts.
Rice. 147. Geographical zonation of the World Ocean (in conjunction with the geographical zones of land) (according to D.V. Bogdanov)
Geographical zones are subdivided into subzones according to the degree of manifestation of zonal features. Theoretically, in each zone, three subzones can be distinguished: the central one, with the most typical features for the zone, and
marginal, bearing some features characteristic of adjacent zones. An example is the forest zone of the temperate zone, in which subzones of the northern, middle and southern taiga, as well as subtaiga (coniferous-deciduous) and broad-leaved forests, are distinguished.
Due to the heterogeneity of the earth's surface and, consequently, the conditions of moisture in different parts of the continents, zones and subzones do not always have a latitudinal strike. Sometimes they stretch almost in a meridional direction, as, for example, in the southern half of North America or in eastern Asia. Therefore, it is more correct to call zonality not latitudinal, but horizontal. In addition, many zones are not distributed around the globe like belts; some of them are found only in the west of the continents, in the east or in their center. This is explained by the fact that the zones were formed as a result of hydrothermal, and not radiation, differentiation of the geographic envelope, i.e., due to the different ratio of heat and moisture. In this case, only the distribution of heat is zonal; the distribution of moisture depends on the distance of the territory from sources of moisture, i.e., from the oceans.
In 1956 A.A. Grigoriev and M.I. Budyko formulated the so-called periodic law of geographical zoning, where each natural zone is characterized by its quantitative ratios of heat and moisture. Heat is estimated in this law by the radiation balance, and the degree of moisture is estimated by the radiation dryness index K B (or RIS) = B / (Z x r), where B is the annual radiation balance, r is the annual amount of precipitation, L is the latent heat of vaporization.
The radiation dryness index shows what proportion of the radiation balance is spent on the evaporation of precipitation: if the evaporation of precipitation requires more heat than it comes from the Sun, and part of the precipitation remains on Earth, then the humidification of such a territory is sufficient or excessive. If more heat comes in than is spent on evaporation, then the excess heat heats the earth's surface, which at the same time experiences a lack of moisture: K B< 0,45 – климат избыточно влажный, К Б = 0,45-Н,0 – влажный, К Б = 1,0-^3,0 – недостаточно влажный, К Б >3.0 - dry.
It turned out that, although zoning is based on the increase in the radiation balance from high latitudes to low latitudes, the landscape appearance of the natural zone is most of all determined by moistening conditions. This indicator determines the type of zone (forest, steppe, desert, etc.), and the radiation balance determines its specific appearance (temperate latitudes, subtropical, tropical, etc.). Therefore, in each geographical zone, depending on the degree of moisture, their own humid and arid natural zones have formed, which can be replaced at the same latitude, depending on the degree of moisture. It is characteristic that in all belts the optimal conditions for the development of vegetation are created when the radiation index of dryness is close to one.
Rice. 148. Periodic law of geographical zonality. K B is the radiation index of dryness. (The diameters of the circles are proportional to the biological productivity of landscapes)
The periodic law of geographic zoning is written in the form of a matrix table, in which the radiation dryness index is calculated horizontally, and the annual radiation balance values \u200b\u200bare vertically (Fig. 148).
Speaking of zoning as a general pattern, it should be borne in mind that it is not equally expressed everywhere. It manifests itself most clearly in the polar, equatorial and equatorial latitudes, as well as in the inland: flat conditions of temperate and subtropical latitudes. The latter include primarily the East European and West Siberian plains, which are elongated in the meridional direction. Apparently, this helped V.V. Dokuchaev to identify the pattern under consideration, since he studied it on the East European Plain. The fact that V.V. Dokuchaev was a soil scientist played a role in determining the complex zonality, and the soil, as is known, is an integral indicator of the natural conditions of the territory.
Some scientists (O. K. Leontiev, A. P. Lisitsyn) trace natural zones in the thickness and at the bottom of the oceans. However, the natural complexes identified by them here cannot be called physiographic zones in the generally accepted sense, i.e., their isolation is not affected by the zonal distribution of radiation - the main cause of zoning on the Earth's surface. Here we can talk about the zonal properties of water masses and bottom sediments of flora and fauna acquired indirectly through water exchange with the near-surface water mass, redeposition of zonal terrigenous and biogenic sediments, and trophic dependence of bottom fauna on dead organic residues coming from above.
The zoning of the geographic envelope as a planetary phenomenon is violated by the opposite property - azonality.
The azonality of a geographic envelope is understood as the distribution of some object or phenomenon out of connection with the zonal features of a given territory. The reason for the azonality is the heterogeneity of the earth's surface: the presence of continents and oceans, mountains and plains on the continents, the peculiarity of moistening conditions and other properties of the geographical envelope. There are two main forms of manifestation of azonality - sectoral geographic zones and altitudinal zonality.
Sectorization, or longitudinal differentiation, of geographic zones is determined by moisture (in contrast to latitudinal zones, where not only moisture, but also heat supply play an important role). Sectorism is manifested primarily in the formation of three sectors within the belts - the continental and two oceanic. However, they are not expressed equally everywhere, which depends on the geographic location of the continent, its size and configuration, as well as on the nature of atmospheric circulation.
Geographic sectoring is most fully expressed on the largest continent of the Earth - in Eurasia, from the Arctic to the equatorial belt inclusive. Longitudinal differentiation is most pronounced here in the temperate and subtropical zones, where all three sectors are clearly expressed. There are two sectors in the tropical zone. Longitudinal differentiation is weakly expressed in the equatorial and subpolar belts.
Another reason for the azonality of the geographic envelope, which violates zoning and sectoring, is the location of mountain systems, which can prevent the penetration of air masses carrying moisture and heat into the depths of the continents. This is especially true for those ridges of the temperate zone, which are located submeridionally on the path of cyclones following from the west.
The azonal nature of landscapes is often determined by the features of the rocks that compose them. Thus, the occurrence of soluble rocks close to the surface leads to the formation of peculiar karst landscapes, which differ significantly from the surrounding zonal natural complexes. In the areas of distribution of water-glacial sands, landscapes of the Polissya type are formed. Figure 149 shows the location of geographic zones and sectors within them on a hypothetical flat continent, built on the basis of the actual distribution of land on the globe at different latitudes. The same figure clearly illustrates the asymmetry of the geographic envelope.
In conclusion, we note that azonality, as well as zoning, is a general pattern. Each area of the earth's surface, due to its heterogeneity, reacts in its own way to the incoming solar energy and, therefore, acquires specific features that are formed against the general zonal background. In essence, azonation is a specific form of manifestation of zonation. Therefore, any part of the earth's surface is simultaneously zonal and azonal.
Altitudinal zonality is a natural change of natural components and natural complexes with an ascent to the mountains from their foot to the peaks. It is due to climate change with height: temperature decrease and precipitation increase up to a certain height (up to 2-3 km) on the windward slopes.
Altitudinal zonality has much in common with horizontal zonality: when ascending mountains, the change of belts occurs in the same sequence as on the plains, when moving from the equator to the poles. However, the natural belts in the mountains are changing much faster than the natural zones in the plains. In the northern hemisphere, in the direction from the equator to the poles, the temperature decreases by about 0.5 ° C for every degree of latitude (111 km), while in the mountains it drops by an average of 0.6 ° C for every 100 m.
Rice. 149. Scheme of geographical zones and main zonal types of landscapes on a hypothetical continent (the dimensions of the depicted continent correspond to half the land area of the globe on a scale of 1: 90,000,000), the configuration - its location in latitudes, the surface - a low plain (according to A. M. Ryabchikov and etc.)
There are other differences: in the mountains in all belts, with a sufficient amount of heat and moisture, there is a special belt of subalpine and alpine meadows, which is not found on the plains. Moreover, each belt of mountains, similar in name to the plain, differs significantly from it, because they receive solar radiation of different composition and have different lighting conditions.
The altitudinal zonality in the mountains is formed not only under the influence of changes in altitude, but also in the features of the relief of the mountains. In this case, the exposure of slopes, both insolation and circulation, plays an important role. Under certain conditions, an inversion of altitudinal zonality is observed in the mountains: when cold air stagnates in intermountain basins, the belt of coniferous forests, for example, can occupy a lower position compared to the belt of broad-leaved forests. On the whole, the altitudinal zonality is much more diverse than the horizontal zonality and, moreover, manifests itself at close distances.
However, there is a close relationship between horizontal zonality and altitudinal zonality. Altitudinal zonality begins in the mountains with an analog of the horizontal zone within which the mountains are located. So, in the mountains located in the steppe zone, the lower belt is mountain-steppe, in the forest - mountain-forest, etc. Horizontal zonality determines the type of altitudinal zonality. In each horizontal zone, mountains have their own range (set) of altitudinal belts. The number of altitudinal belts depends on the height of the mountains and their location. The higher the mountains and the closer to the equator they are located, the richer their spectrum of belts.
The nature of the altitudinal zonality is also affected by the sector nature of the geographic envelope: the composition of the vertical belts differs depending on which particular sector a particular mountain range is located in. The generalized structure of the altitudinal zonality of landscapes in different geographical zones (at different latitudes) and in various sectors is shown in Figure 150. Similarly to the altitudinal zonality in mountains on land, one can speak of deep zonality in the ocean.
One of the main (and according to Academician K.K. Markov, the main) regularities of the geographic envelope should be considered polar asymmetry. The reason for this pattern is primarily the asymmetry of the figure of the Earth. As you know, the northern semi-axis of the Earth is 30 m longer than the southern one, so that the Earth is more flattened at the South Pole. The location of continental and oceanic masses on the Earth is asymmetrical. In the northern hemisphere, land occupies 39% of the area, and in the southern hemisphere - only 19%. Around the North Pole is the ocean, around the South - the mainland of Antarctica. On the southern continents, platforms occupy from 70 to 95% of their area, on the northern continents - 30 - 50%. In the northern hemisphere there is a belt of young folded structures (Alpine-Himalayan), stretching in a latitudinal direction. It has no analogue in the southern hemisphere. In the northern hemisphere, between 50 and 70 °, the most geostructurally elevated land areas are located (Canadian, Baltic, Anabar. Aldan shields). In the southern hemisphere at these latitudes there is a chain of oceanic depressions. In the northern hemisphere there is a continental ring framing the polar ocean, in the southern hemisphere there is an oceanic ring that borders the polar continent.
The asymmetry of land and sea entails the asymmetry of other components of the geographic envelope. Thus, in the oceanosphere, the systems of sea currents in the northern and southern hemispheres do not repeat each other; moreover, warm currents in the northern hemisphere extend up to arctic latitudes, while in the southern hemisphere only up to a latitude of 35°. The water temperature in the northern hemisphere is 3° higher than in the southern.
The climate of the northern hemisphere is more continental than the southern one (annual air temperature amplitude is 14 and 6 °C, respectively). In the northern hemisphere, there is weak continental glaciation, strong sea glaciation, and a large area of permafrost. In the southern hemisphere, these figures are directly opposite. In the northern hemisphere, the taiga zone occupies a huge area, in the southern hemisphere it has no analogue. Moreover, at latitudes where broad-leaved and mixed forests dominate in the northern hemisphere (~50°), arctic deserts are located on islands in the southern hemisphere. The fauna of the hemispheres is also different. In the southern hemisphere, there are no zones of tundra, forest-tundra, forest-steppe, and deserts of the temperate zone. The fauna of the hemispheres is also different. In the south there are no bactrian camels, walruses, polar bears and many other animals, but there are, for example, penguins, marsupials and some other animals that are not in the northern hemisphere. In general, the differences in the species composition of plants and animals between the hemispheres are very significant.
These are the basic laws of the geographic shell, some of them are sometimes called laws. However, as D. L. Armand convincingly proved, physical geography does not deal with laws, but with regularities - steadily repeating relationships between phenomena in nature, but having a lower rank than laws.
rice. 150. Generalized structure of altitudinal zonality of landscapes in different geographical zones (according to Ryabchikov A.A.)
Describing the geographic shell, it is necessary to emphasize once again that it is closely connected with the outer space surrounding it and with the internal parts of the Earth. First of all, it receives the energy it needs from the Cosmos. The forces of attraction keep the Earth in orbit around the Sun and cause periodic tidal disturbances in the body of the planet. Corpuscular streams (“solar wind”), X-rays and ultraviolet rays, radio waves and visible radiant energy are directed towards the Earth from the Sun. Cosmic rays are directed from the depths of the Universe towards the Earth. The streams of these rays and particles cause the formation of magnetic storms, auroras, air ionization and other phenomena near the Earth. The mass of the Earth is constantly increasing due to the fall of meteorites and cosmic dust. But the Earth perceives the impact of the Cosmos non-passively. Around the Earth as a planet with a magnetic field and radiation belts, a specific natural system is being created, which is called geographic space. It extends from the magnetopause - the upper boundary of the Earth's magnetic field, which is located at a height of at least 10 Earth radii, to the lower boundary of the Earth's crust - the so-called Mohorovichich (Moho) surface. Geographical space is divided into four parts (from top to bottom):
Near space. Its lower boundary runs along the upper boundary of the atmosphere at an altitude of 1500 - 2000 km above the Earth. Here the main interaction of cosmic factors with the magnetic and gravitational fields of the Earth takes place. Here the corpuscular radiation of the Cosmos, which is detrimental to living organisms, lingers.
High atmosphere. From below, it is limited by the stratopause, which in this case is also taken as the upper boundary of the geographic envelope. Here, primary cosmic rays slow down, they are transformed, and the thermosphere is heated.
Geographic cover. Its lower boundary is the base of the weathering crust in the lithosphere.
Underlying bark. The lower boundary is the Moho surface. This is the area of manifestation of endogenous factors that form the primary relief of the planet.
The concept of geographical space specifies the position of the geographic envelope of our planet.
In conclusion, we note that a person in the course of his economic activity currently has a great influence on the geographical envelope.
Geographical shell - in Russian geographical science, this is understood as an integral and continuous shell of the Earth, where its constituent parts: the upper part of the lithosphere (the earth's crust), the lower part of the atmosphere (troposphere, stratosphere, hydrosphere and biosphere) - as well as the anthroposphere penetrate each other and are in close interaction. Between them there is a continuous exchange of matter and energy.
The upper boundary of the geographic shell is drawn along the stratopause, since before this boundary the thermal effect of the earth's surface affects atmospheric processes; the boundary of the geographic shell in the lithosphere is often combined with the lower limit of the hypergenesis region (sometimes the foot of the stratisphere, the average depth of seismic or volcanic sources, the sole of the earth's crust, and the level of zero annual temperature amplitudes are taken as the lower boundary of the geographic shell). The geographic envelope completely covers the hydrosphere, descending in the ocean 10-11 km below sea level, the upper zone of the earth's crust and the lower part of the atmosphere (a layer 25-30 km thick). The greatest thickness of the geographical envelope is close to 40 km. The geographical shell is the object of study of geography and its branch sciences.
Despite the criticism of the term "geographical envelope" and the difficulty in defining it, it is actively used in geography and is one of the main concepts in Russian geography.
The concept of the geographic envelope as the "outer sphere of the earth" was introduced by the Russian meteorologist and geographer P. I. Brounov (1910). The modern concept was developed and introduced into the system of geographical sciences by A. A. Grigoriev (1932). The history of the concept and controversial issues are most successfully considered in the works of I. M. Zabelin.
Concepts analogous to the concept of a geographic envelope also exist in foreign geographical literature (the earth envelope of A. Getner and R. Hartshorne, the geosphere of G. Karol, etc.). However, there the geographical envelope is usually considered not as a natural system, but as a combination of natural and social phenomena.
There are other terrestrial shells at the boundaries of the connection of various geospheres.
2 STRUCTURE OF THE GEOGRAPHICAL SHELL
Let us consider the main structural elements of the geographic envelope.
The earth's crust is the upper part of the solid earth. It is separated from the mantle by a boundary with a sharp increase in the velocities of seismic waves - the Mohorovichich boundary. The thickness of the crust ranges from 6 km under the ocean to 30-50 km on the continents. There are two types of crust - continental and oceanic. Three geological layers are distinguished in the structure of the continental crust: sedimentary cover, granite and basalt. The oceanic crust is composed mainly of mafic rocks, plus a sedimentary cover. The earth's crust is divided into lithospheric plates of different sizes, moving relative to each other. The kinematics of these movements is described by plate tectonics. 
Figure 1 - The structure of the borrowed crust
There is a crust on Mars and Venus, the Moon and many satellites of the giant planets. On Mercury, although it belongs to the terrestrial planets, there is no terrestrial-type crust. In most cases, it consists of basalts. The Earth is unique in that it has two types of crust: continental and oceanic.
The mass of the earth's crust is estimated at 2.8 1019 tons (of which 21% is oceanic crust and 79% is continental). The crust makes up only 0.473% of the total mass of the Earth
The oceanic crust consists mainly of basalts. According to the theory of plate tectonics, it continuously forms at mid-ocean ridges, diverges from them, and is absorbed into the mantle in subduction zones. Therefore, the oceanic crust is relatively young, and its oldest sections date back to the Late Jurassic.
The thickness of the oceanic crust practically does not change with time, since it is mainly determined by the amount of melt released from the mantle material in the zones of mid-ocean ridges. To some extent, the thickness of the sedimentary layer at the bottom of the oceans has an effect. In different geographical areas, the thickness of the oceanic crust varies between 5-7 kilometers.
As part of the stratification of the Earth by mechanical properties, the oceanic crust belongs to the oceanic lithosphere. The thickness of the oceanic lithosphere, unlike the crust, depends mainly on its age. In the zones of mid-ocean ridges, the asthenosphere comes very close to the surface, and the lithospheric layer is almost completely absent. With distance from the zones of mid-ocean ridges, the thickness of the lithosphere first increases in proportion to its age, then the growth rate decreases. In subduction zones, the thickness of the oceanic lithosphere reaches its greatest values, amounting to 120-130 kilometers.
The continental crust has a three-layer structure. The upper layer is represented by a discontinuous cover of sedimentary rocks, which is widely developed, but rarely has a large thickness. Most of the crust is folded under the upper crust, a layer composed mainly of granites and gneisses, of low density and ancient history. Studies show that most of these rocks were formed very long ago, about 3 billion years ago. Below is the lower crust, consisting of metamorphic rocks - granulites and the like.
The Earth's crust is made up of a relatively small number of elements. About half of the mass of the earth's crust is oxygen, more than 25% is silicon. Only 18 elements: O, Si, Al, Fe, Ca, Na, K, Mg, H, Ti, C, Cl, P, S, N, Mn, F, Ba - make up 99.8% of the mass of the earth's crust.
Determination of the composition of the upper continental crust was one of the first tasks that the young science of geochemistry undertook to solve. Actually, geochemistry appeared from attempts to solve this problem. This task is very difficult, since the earth's crust consists of many rocks of various compositions. Even within the same geological body, the composition of rocks can vary greatly. In different areas, completely different types of rocks can be distributed. In the light of all this, the problem arose of determining the general, average composition of that part of the earth's crust that comes to the surface on the continents. On the other hand, the question immediately arose about the content of this term.
The next attempt to determine the average composition of the earth's crust was made by Viktor Goldshmidt. He made the assumption that the glacier, moving along the continental crust, scrapes off all the rocks that come to the surface, mixes them. As a result, rocks deposited by glacial erosion reflect the composition of the middle continental crust. Goldschmidt analyzed the composition of banded clays deposited in the Baltic Sea during the last glaciation. Their composition was surprisingly close to the average composition obtained by Clark. The agreement of the estimates obtained by such different methods was a strong confirmation of the geochemical methods.
Subsequently, many researchers were engaged in determining the composition of the continental crust. The estimates of Vinogradov, Vedepol, Ronov and Yaroshevsky received wide scientific recognition.
Some new attempts to determine the composition of the continental crust are based on its division into parts formed in different geodynamic settings.
The upper limit of the troposphere is located at an altitude of 8-10 km in polar, 10-12 km in temperate and 16-18 km in tropical latitudes; lower in winter than in summer. The lower, main layer of the atmosphere. It contains more than 80% of the total mass of atmospheric air and about 90% of all water vapor present in the atmosphere. In the troposphere, turbulence and convection are highly developed, clouds appear, cyclones and anticyclones develop. The temperature decreases with increasing altitude with an average vertical gradient of 0.65°/100 m.
For "normal conditions" at the Earth's surface are taken: density 1.2 kg/m3, barometric pressure 101.34 kPa, temperature plus 20 °C and relative humidity 50%. These conditional indicators have a purely engineering value.
Stratosphere (from Latin stratum - flooring, layer) - a layer of the atmosphere, located at an altitude of 11 to 50 km. A slight change in temperature in the 11-25 km layer (lower layer of the stratosphere) and its increase in the 25-40 km layer from -56.5 to 0.8 C (upper stratosphere or inversion region) are typical. Having reached a value of about 273 K (almost 0 °C) at an altitude of about 40 km, the temperature remains constant up to an altitude of about 55 km. This region of constant temperature is called the stratopause and is the boundary between the stratosphere and the mesosphere.
It is in the stratosphere that the ozonosphere layer ("ozone layer") is located (at an altitude of 15-20 to 55-60 km), which determines the upper limit of life in the biosphere. Ozone (O3) is formed as a result of photochemical reactions most intensively at an altitude of ~30 km. The total mass of O3 at normal pressure would be a layer 1.7-4.0 mm thick, but even this is enough to absorb the solar ultraviolet radiation that is harmful to life. The destruction of O3 occurs when it interacts with free radicals, NO, halogen-containing compounds (including "freons").
Most of the short-wavelength part of ultraviolet radiation (180-200 nm) is retained in the stratosphere and the energy of short waves is transformed. Under the influence of these rays, magnetic fields change, molecules break up, ionization, new formation of gases and other chemical compounds occur. These processes can be observed in the form of northern lights, lightning and other glows.
In the stratosphere and higher layers, under the influence of solar radiation, gas molecules dissociate - into atoms (above 80 km, CO2 and H2 dissociate, above 150 km - O2, above 300 km - H2). At an altitude of 200–500 km, ionization of gases also occurs in the ionosphere; at an altitude of 320 km, the concentration of charged particles (О+2, О−2, N+2) is ~ 1/300 of the concentration of neutral particles. In the upper layers of the atmosphere there are free radicals - OH, HO 2, etc.
There is almost no water vapor in the stratosphere.
Troposphere (ancient Greek τροπή - “turn”, “change” and σφαῖρα - “ball”) - the lower, most studied layer of the atmosphere, 8-10 km high in the polar regions, up to 10-12 km in temperate latitudes, at the equator - 16-18 km.
When rising in the troposphere, the temperature drops by an average of 0.65 K every 100 m and reaches 180÷220 K (-90÷-53° C) in the upper part. This upper layer of the troposphere, in which the decrease in temperature with height stops, is called the tropopause. The next layer of the atmosphere above the troposphere is called the stratosphere.
More than 80% of the total mass of atmospheric air is concentrated in the troposphere, turbulence and convection are highly developed, the predominant part of water vapor is concentrated, clouds arise, atmospheric fronts form, cyclones and anticyclones develop, as well as other processes that determine weather and climate. The processes occurring in the troposphere are primarily due to convection.
The part of the troposphere within which glaciers can form on the earth's surface is called the ionosphere.
The hydrosphere (from other Greek Yδωρ - water and σφαῖρα - ball) is the water shell of the Earth.
It forms a discontinuous water shell. The average depth of the ocean is 3850 m, the maximum (Pacific Mariana Trench) is 11,022 meters. About 97% of the mass of the hydrosphere is saline ocean water, 2.2% is glacier water, the rest is groundwater, lake and river fresh water. The total volume of water on the planet is about 1,532,000,000 cubic kilometers. The mass of the hydrosphere is approximately 1.46 * 10 21 kg. This is 275 times the mass of the atmosphere, but only 1/4000 of the mass of the entire planet. The hydrosphere is 94% water of the World Ocean, in which salts are dissolved (on average 3.5%), as well as a number of gases. The upper layer of the ocean contains 140 trillion tons of carbon dioxide and 8 trillion tons of dissolved oxygen. The area of the biosphere in the hydrosphere is represented in its entire thickness, however, the highest density of living matter falls on the surface layers heated and illuminated by the rays of the sun, as well as coastal zones.
In general, the division of the hydrosphere into the World Ocean, continental waters and groundwaters is accepted. Most of the water is concentrated in the ocean, much less - in the continental river network and groundwater. There are also large reserves of water in the atmosphere, in the form of clouds and water vapor. Over 96% of the volume of the hydrosphere is seas and oceans, about 2% is groundwater, about 2% is ice and snow, and about 0.02% is land surface water. Part of the water is in a solid state in the form of glaciers, snow cover and permafrost, representing the cryosphere.
Surface waters, although occupying a relatively small share in the total mass of the hydrosphere, nevertheless play an important role in the life of the terrestrial biosphere, being the main source of water supply, irrigation and watering.
Biosphere (from other Greek βιος - life and σφαῖρα - sphere, ball) - the shell of the Earth inhabited by living organisms, under their influence and occupied by the products of their vital activity; "film of life"; global ecosystem of the Earth.
The biosphere is the shell of the Earth inhabited by living organisms and transformed by them. The biosphere began to form no later than 3.8 billion years ago, when the first organisms began to emerge on our planet. It penetrates the entire hydrosphere, the upper part of the lithosphere and the lower part of the atmosphere, that is, it inhabits the ecosphere. The biosphere is the totality of all living organisms. It is home to over 3,000,000 species of plants, animals, fungi and bacteria. Man is also a part of the biosphere, his activity surpasses many natural processes and, as V. I. Vernadsky said: "Man becomes a powerful geological force."
French naturalist Jean Baptiste Lamarck at the beginning of the 19th century. for the first time proposed in fact the concept of the biosphere, without even introducing the term itself. The term "biosphere" was coined by the Austrian geologist and paleontologist Eduard Suess in 1875.
A holistic doctrine of the biosphere was created by the biogeochemist and philosopher V. I. Vernadsky. For the first time, he assigned to living organisms the role of the main transforming force of the planet Earth, taking into account their activity not only at the present time, but also in the past.
There is another, broader definition: Biosphere - the area of distribution of life on the cosmic body. While the existence of life on space objects other than the Earth is still unknown, it is believed that the biosphere can extend to them in more hidden areas, for example, in lithospheric cavities or in subglacial oceans. For example, the possibility of the existence of life in the ocean of Jupiter's moon Europa is considered.
The biosphere is located at the intersection of the upper part of the lithosphere and the lower part of the atmosphere and occupies almost the entire hydrosphere.
Upper boundary in the atmosphere: 15-20 km. It is determined by the ozone layer, which blocks the short-wave ultraviolet, which is harmful to living organisms.
Lower boundary in the lithosphere: 3.5-7.5 km. It is determined by the temperature of the transition of water into steam and the temperature of denaturation of proteins, however, in general, the spread of living organisms is limited to a depth of several meters.
The boundary between the atmosphere and the lithosphere in the hydrosphere: 10-11 km. Determined by the bottom of the World Ocean, including bottom sediments.
The biosphere is made up of the following types of substances:
Living matter - the totality of the bodies of living organisms inhabiting the Earth, is physico-chemically unified, regardless of their systematic affiliation. The mass of living matter is relatively small and is estimated at 2.4 ... 3.6 1012 tons (in dry weight) and is less than one millionth of the entire biosphere (about 3 1018 tons), which, in turn, is less than one thousandth the masses of the earth. But this is one "of the most powerful geochemical forces of our planet", since living matter does not just inhabit the biosphere, but transforms the face of the Earth. Living matter is distributed within the biosphere very unevenly.
Biogenic substance - a substance created and processed by living matter. During the course of organic evolution, living organisms have passed through their organs, tissues, cells, and blood a thousand times over the entire atmosphere, the entire volume of the world's oceans, and a huge mass of mineral substances. This geological role of living matter can be imagined from the deposits of coal, oil, carbonate rocks, etc.
Inert matter - products formed without the participation of living organisms.
Bio-inert substance, which is created simultaneously by living organisms and inert processes, representing dynamically balanced systems of both. Such are soil, silt, weathering crust, etc. Organisms play a leading role in them.
A substance undergoing radioactive decay.
Scattered atoms, continuously created from any kind of terrestrial matter under the influence of cosmic radiation.
A substance of cosmic origin.
The entire layer of the impact of life on inanimate nature is called the megabiosphere, and together with the artebiosphere - the space of humanoid expansion in the near-Earth space - the panbiosphere.
The substrate for life in the atmosphere of microorganisms (aerobionts) is water droplets - atmospheric moisture, the source of energy - solar energy and aerosols. Approximately from the tops of the trees to the height of the most frequent location of cumulus clouds extends the tropobiosphere (with tropobionts; this space is a thinner layer than the troposphere). A layer of extremely sparse microbiota, the altobiosphere (with altobionts), grows above. Above that stretches the space where organisms enter randomly and infrequently and do not reproduce - the parabiosphere. Above is the apobiosphere.
The geobiosphere is inhabited by geobionts, the substrate, and partly the living environment for which the earth's firmament serves. The geobiosphere consists of the area of life on the land surface - the terrabiosphere (with terrabionts), divided into the phytosphere (from the surface of the earth to the tops of the trees) and the pedosphere (soils and subsoils; sometimes the entire weathering crust is included here) and life in the depths of the Earth - the lithobiosphere (with lithobionts living in the pores of rocks, mainly in groundwater). At high altitudes in the mountains, where the life of higher plants is no longer possible, the high-altitude part of the terrabiosphere is located - the eolian zone (with eolobionts). The lithobiosphere breaks up into a layer where the life of aerobes is possible - the hypoterrabiosphere and a layer where only anaerobes can live - the tellurobiosphere. Life in an inactive form can penetrate deeper into the hypobiosphere. Metabiosphere - all biogenic and bioinert rocks. Deeper is the abiosphere.
In the depths of the lithosphere, there are 2 theoretical levels of the spread of life - an isotherm of 100 ° C, below which water boils at normal atmospheric pressure, and an isotherm of 460 ° C, where at any pressure water turns into steam, i.e. it cannot be in a liquid state .
The hydrobiosphere - the entire global layer of water (without groundwater), inhabited by hydrobionts - breaks up into a layer of continental waters - the aquabiosphere (with aquatic organisms) and the area of seas and oceans - the marinobiosphere (with marinobionts). There are 3 layers - a relatively brightly illuminated photosphere, always a very twilight disphotosphere (up to 1% of solar insolation) and a layer of absolute darkness - the aphotosphere.
The concept of "geographical shell"
Remark 1
The geographic shell is a continuous and integral shell of the Earth, consisting of the earth's crust, troposphere, stratosphere, hydrosphere, biosphere and anthroposphere. All components of the geographic envelope are in close interaction and penetrate each other. Between them there is a constant exchange of matter and energy.
The upper boundary of the geographical envelope is the stratosphere, located below the maximum ozone concentration at an altitude of about 25 km. The lower boundary passes in the upper layers of the lithosphere (from 500 to 800 m).
Mutual penetration into each other and the interaction of the components that make up the geographical shell - water, air, mineral and living shells - determines its integrity. In it, in addition to the continuous metabolism and energy, one can also observe the constant circulation of substances. Each component of the geographic shell, developing according to its own laws, is influenced by the other shells and itself affects them.
The impact of the biosphere on the atmosphere is associated with the process of photosynthesis, as a result of which there is an intensive gas exchange between living matter and air, as well as regulation of gases in the atmosphere. Green plants absorb carbon dioxide from the air and release oxygen, without which the life of most living organisms on the planet is impossible. Thanks to the atmosphere, the earth's surface is not overheated by solar radiation during the day and does not cool significantly at night, which is necessary for the normal existence of living beings.
The biosphere influences the hydrosphere. Living organisms can affect the salinity of the waters of the World Ocean, taking from the water some substances necessary for their life (for example, calcium is needed to form shells, shells, skeletons). The aquatic environment is the habitat of many living beings, water is necessary for the normal course of most of the life processes of representatives of the flora and fauna.
The influence of living organisms on the earth's crust is most pronounced in its upper part, where the accumulation of plant and animal remains occurs, and rocks of organic origin are formed.
Living organisms take an active part not only in the creation of rocks, but also in their destruction. They secrete acids that destroy rocks, affecting the roots, forming deep cracks. As a result of these processes, hard and dense rocks turn into loose sedimentary ones (pebbles, gravel). All conditions are created for the formation of one or another type of soil.
A change in any one component of the geographic shell is reflected in all other shells. For example, the era of the great glaciation in the Quaternary period. The expansion of the land surface created the prerequisites for the onset of a drier and colder climate, which led to the formation of a layer of ice and snow that covered large areas in northern North America and Eurasia. This, in turn, led to a change in the flora, fauna, and soil cover.
Geographic Shell Components
The main components of the geographic envelope include:
- Earth's crust. Upper part of the lithosphere. It is separated from the mantle by the Mohorovich boundary, which is characterized by a sharp increase in seismic wave velocities. The thickness of the earth's crust ranges from six kilometers (under the ocean) to 30-50 km (on the continents). There are two types of earth's crust: oceanic and continental. The oceanic crust consists mainly of mafic rocks and sedimentary cover. Basalt and granite layers, sedimentary cover are distinguished in the continental crust. The earth's crust consists of separate lithospheric plates of different sizes, moving relative to each other.
- Troposphere. The lower layer of the atmosphere. The upper limit in polar latitudes is 8-10 km, in temperate latitudes 10-12 km, in tropical latitudes 16-18 km. In winter, the upper limit is somewhat lower than in summer. The troposphere contains 90% of the total water vapor in the atmosphere and 80% of the total air mass. It is characterized by convection and turbulence, cloudiness, development of cyclones and anticyclones. As the altitude increases, the temperature decreases.
- Stratosphere. Its upper limit is at an altitude of 50 to 55 km. As the altitude increases, the temperature approaches 0 ºС. Characteristic: low content of water vapor, low turbulence, increased ozone content (its maximum concentration is observed at an altitude of 20-25 km.).
- Hydrosphere. Includes all water resources of the planet. The largest amount of water resources is concentrated in the World Ocean, less - in groundwater and the continental network of rivers. Large reserves of water are contained in the form of water vapor and clouds in the atmosphere. Part of the water is stored in the form of ice and snow, forming the cryosphere: snow cover, glaciers, permafrost.
- Biosphere. The totality of those parts of the components of the geographic shell (lithosphere, atmosphere, hydrosphere) that are inhabited by living organisms.
- Anthroposphere, or noosphere. The sphere of interaction between the environment and man. The recognition of this shell is not supported by all scientists.
Stages of development of the geographical shell
The geographical envelope at the present stage is the result of a long development, during which it constantly became more complicated.
Stages of development of the geographical envelope:
- The first stage is prebiogenic. It lasted 3 billion years. At that time, only the simplest organisms existed. They played little part in the development and formation of the geographical envelope. The atmosphere was characterized by a high content of carbon dioxide and a low content of oxygen.
- Second phase. Duration - about 570 million years. It is characterized by the dominant role of living organisms in the formation of the geographical envelope. Organisms affected all components of the shell: the composition of the atmosphere and water changed, and the accumulation of rocks of organic origin was observed. At the end of the stage, people appeared.
- The third stage is modern. It began 40 thousand years ago. It is characterized by the active influence of human activity on various components of the geographic envelope.
