Date of: 30.11.2019

Relief

At the heart of the mainland lies the ancient African-Arabian platform, which forms the predominantly flat relief of the continent. The relief of Africa is dominated by plains, plateaus and plateaus, located at an altitude of 200-500 m above sea level (39% of the area) and 500-1000 m above sea level (28.1% of the area). Lowlands occupy only 9.8% of the area and are located mainly along the coastal margins. In terms of average height above sea level (750 m), Africa is second only to Antarctica and Eurasia.

Almost all of Africa north of the equator is occupied by the plains and plateaus of the Sahara and Sudan, among which the Akhaggar and Tibesti highlands rise in the center of the Sahara (Mt. Ami-Kussi, height 3415 m), in Sudan - the Darfur plateau (Mr. Marra, 3088 m) . In the northwest, the Atlas Mountains (Tubkal, 4165 m) rise above the plains of the Sahara; in the east, along the Red Sea, the Etbai Range (Oda, 2259 m) stretches. The plains of Sudan from the south are framed by the North Guinean Upland (Bintimani, 1948 m) and the Azande Plateau; from the east, the Ethiopian highlands rise above them (the city of Ras-Dashen; 4620). It abruptly breaks off to the Afar depression, where the deepest depression in Africa is located (Lake Assal, 150 m).

The Congo Depression is bounded from the west by the South Guinean Upland, from the south by the Lunda-Katanga Plateau, from the east by the East African Plateau, on which rise the highest peaks of Africa - Mount Kilimanjaro (5895 m), Rwenzori (5109 m).

South Africa is occupied by the high plains of the Kalahari, framed from the west by the plateaus of Namaqualand, Damaraland, Kaoko, from the east by the Dragon Mountains (Tabana-Ntlenyana, 3482 m). Along the southern edge of the mainland stretch the medium-altitude Cape Mountains. The predominance of the leveled relief is due to the platform structure of the mainland.

In the northwestern part of Africa, with a deep basement and a wide development of the sedimentary cover, heights of less than 1000 m predominate ( Low Africa); southwest Africa is characterized by heights of more than 1000 m ( High Africa). Troughs and protrusions of the African platform correspond to large depressions (Kalahari, Congo, Chadian, etc.).

The eastern margin of Africa is more uplifted and fragmented within the activated area of ​​the platform - the Ethiopian Highlands, the East African Plateau, where it extends a complex system East African faults. In the uplifted regions of High Africa, the largest area is occupied by basement plains and basement blocky mountains, framing the depressions of East Africa (including Rwenzori) and Katanga. In Low Africa, basement ridges and massifs, stretching along the coast of the Gulf of Guinea, protrude into the Sahara (in the Ahaggar, Tibesti, Etbai ranges). Lava plateaus and cones, common in the Ethiopian Highlands and East Africa (Kilimanjaro, Kenya, etc.), crown the peaks of Ahaggar and Tibesti, are in Sudan (Marra), Cameroon (Cameroon Volcano, Adamawa Mountains), cover the Dragon Mountains in Lesotho.

With faults earth's crust the processes of volcanism are connected, which are the cause of the formation of high uplands and volcanic peaks. Mountains of Africa different ages: old ones are located in the south (Draconic and Cape), young ones (Atlas) - in the north.

Geological structure and minerals

Almost all of Africa, except for the Atlas Mountains in the northwest and the Cape Mountains in the extreme south, is ancient platform, which also included the Arabian Peninsula and about. Madagascar with the Seychelles.

At the heart of the mainland lies the old African-Arabian platform with significantly destroyed folded formations. In the south and east of the mainland, the crystalline basement comes to the surface. Here is a zone of deep faults in the earth's crust: handfuls (uplift) - the Ethiopian Highlands, the East African Plateau, the Dragon Mountains, grabens (lowering) - the Nyasa and Tanganyika basins. Mobile folded zones adjoin the platform: in the north - the Atlas, in the south - the Cape Mountains.

The foundation of the African-Arabian platform, composed of Precambrian rocks, mostly folded and metamorphosed, protrudes in many parts of Africa - from the Anti-Atlas and Western Arabia to the Transvaal. The basement includes rocks of all age subdivisions of the Precambrian, from the Lower Archean (more than 3 Ga) to the upper Proterozoic. The consolidation of most of Africa was completed by the middle of the Proterozoic (1.9-1.7 billion years ago); in the late Proterozoic, only peripheral (Mauritano-Senegalese, Arabian) and some internal (Western Congolese) geosynclinal systems developed, and by the beginning of the Paleozoic, the entire area of ​​\u200b\u200bthe modern platform was stabilized.

The rocks of the early Precambrian basement are represented by various crystalline schists, gneisses, metamorphosed volcanic formations, and are replaced by granites over large areas. They are characterized by deposits of iron ores, gold (in connection with granites), chromites. Large accumulations of gold and uranium ores are known in the clastic rocks of the base of the sedimentary cover in southern Africa.

Younger, weakly metamorphosed rocks of the Upper Proterozoic contain deposits of tin, tungsten (in or near granites), copper, lead, zinc, and uranium ores. Powerful volcanic eruptions and eruptions of the main (basaltic) magma belong to the beginning of the Jurassic, most common in South Africa, but also found in western North Africa. By the same time (the end of the Jurassic) is the formation of the modern contours of Africa, associated with the subsidence along the ruptures of the bottom of the Indian and Atlantic oceans and the formation of a system of perioceanic troughs containing significant deposits of oil and gas (Nigeria, Gibon, Angola, etc.).

Madagascar separated from the continent at the end of the Paleozoic. At the same time, the modern coast of Tunisia and Libya was intensively submerged by the formation of oil deposits in the Cretaceous and Eocene deposits. In the middle and end of the Cretaceous, a significant transgression of the sea engulfed the Sahara Plate: sea straits arose that connected the Mediterranean Sea and the Gulf of Guinea and existed until the middle of the Eocene.

Africa has large deposits of iron ores (total reserves are estimated at about 16-23 billion tons), manganese ores (about 400 million tons), chromites (500-700 million tons), bauxite (3.3 billion tons), copper (reliable and probable reserves of about 48 million tons), cobalt (0.5 million tons), phosphorites (26 billion tons), antimony, lithium, uranium, asbestos, gold (Africa provides about 80% of the world's total production), platinum and platinoids (about 60 % of production), diamonds (98% of production). After the Second World War, large deposits of oil (total reserves are estimated at 5.6 billion tons) and natural gas were discovered in Africa (mainly in Algeria, Libya and Nigeria).

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FGP, research historyClimatic conditions

see also

Africa. Physical and geographical position. History of research and development

Relief of Russia characterized by three main features:

• it is diverse, that is, there are both high mountains and vast plains;
• 2/3 of the territory is occupied by plains;
• mountains are located mainly on the southern and eastern outskirts of the country.

These features are explained by the large size of the territory, its diverse tectonic structure, and the location of the main tectonic structures. Plains are located on platforms, mountains have arisen within folded areas.

The territory of the country is located on two ancient(Russian and Siberian) and three young(West Siberian, Scythian and Turan) platforms, as well as in three folded belts(Alpine-Himalayan (Mediterranean), Ural-Mongolian, Pacific). Within ancient platforms stand out four shields. On the East European platform, these are the Baltic and Ukrainian shields, on the Siberian platform, the Aldan and Anabar shields.

IN western part The country is the East European (Russian) plain, it is located on the ancient Russian platform. The relief of the plain is diverse - it is characterized by an alternation of lowlands (Upper Volga, Meshcherskaya) and uplands (Valdai, Central Russian, Smolensk-Moscow). In its southern part, there is the Caspian lowland located below sea level. Here is the lowest (-28 m) point of the country. The average height of the Russian Plain is about 200 m. The Ural Mountains are located along its eastern outskirts. These low (max. height 1894 m - Mount Narodnaya) mountains stretched from north to south - from the Arctic Ocean to the steppes of Kazakhstan.

TO east from the Urals there is a vast West Siberian Plain. Half of it has a height of less than 100 m, and only at the edges of a height of 150-200 m. To the east of it, between the Lena and the Yenisei, lies the Central Siberian Plateau, located on the ancient Siberian platform. Its average height is 500-700 m, the maximum is 1701 m.

TO south from the Russian Plain are the highest ( Elbrus 5642 m) the mountains of Russia - the Caucasus.

In the upper reaches of the Ob and Yenisei are the Altai (Belukha Mountain, 4506 m) and Sayan (8) ranges. From the east, the mountains of the Baikal and Transbaikalia adjoin the Sayans: the Stanovoye Upland, the Stanovoy Range. East

The Central Siberian plateau lies the Verkhoyansk and Chersky ranges. On Far East along the shore Pacific Ocean the Sikhote-Alin ridge stretches. There are high mountains on the Kamchatka Peninsula (Klyuchevskaya Sopka volcano, 4750 m).

On the territory of Russia there are active and extinct volcanoes . The active ones are located on the Kamchatka Peninsula and the Kuril Islands, the extinct ones are in the Caucasus, the Far East, and Transbaikalia. All the largest volcanoes are located on the Kamchatka Peninsula: Klyuchevskaya Sopka (the highest), Avachinskaya Sopka, Ichinskaya Sopka, Kronotskaya Sopka, etc.

About 25% of the territory of Russia may be subject to earthquakes with a magnitude of at least 7.0. The most earthquake-prone region of the country is the Pacific coast.

Circle Native land Grade 6

Subject; relief features and minerals of Rtishchevo

Target:The development of the student's personality on the basis of the assimilation of local history content.

Tasks: Using the map as informational, figurative-sign models of reality.

Understanding the meaning of one's own activity and personal qualities.

Awareness of the role of the course in the comprehensive study of Russia.

Lesson type:a lesson in discovering new knowledge

In the lessons of geography, history, you studied ways and methods research work Let's remember them

Speaking about the etymology of the word "research", we note that this concept contains an indication of extracting something "from the trace", i.e. restore a certain order of things by indirect signs, random objects. Therefore, we must be able to compare, analyze facts and predict the situation,

Basically, you listed active forms of research. But there are others:

Do you think silent reading of literature is a form and method of research? Why?

When working with text, you need to see

information:

Factual (which is explicitly stated in the text)

Subtext (which is implicitly reported in the text, read "between the lines")

Conceptual (the main idea of ​​the text, its main meanings)

Students repeat the material, study the memo

selection of bases and criteria for comparison, seriation,

classification of objects;

Statement of the learning task

Today we will work with tests, but not simple ones, but with the text of the card. What can we learn from physical map? That is, we can also highlight the factual, subtext, conceptual parts

Students make assumptions and determine the topic: gp and relief

formulation of the cognitive goal;

"Discovery" of new knowledge by students

The city of Rtishchevo is located on the western outskirts of the Volga Upland, 214 km northwest of Saratov. It occupies an area of ​​32.95 km². The length of the city is 5.25 km long and 4.5 km wide, the height above sea level is about 210 meters.

The surface of the territory of the city of Rtishchevo, located in the southeastern part of the Oka-Donskaya lowland on the Don Plain, is a flat-undulating, slightly hilly plain, in varying degrees dissected by an erosional network. There are quite a lot of ravines on the territory of the city: in the west - Popov, in the north-west - Krasny Luch, in the south-west - Tretyak and in the south - Oak. Ponds with an area of ​​about 15,000 m2 and about 12,000 m2, respectively, have been built in the Krasny Luch and Dubovy ravines.

Several small rivers flow within the city of Rtishchevo, the largest of which are the tributaries of the Khopra - Olshanka and Iznair. The Olshanka River flows through northern border city ​​and is one of the water intakes of its hydraulic system. The Iznair River flows south of Rtishchevo. Water from it was used for the needs of the city from 1940 until the construction of a water pipeline from the Khoper River in the late 1980s.

According to hydrogeological zoning, the territory of the city of Rtishchevo belongs to the Sursko-Khopyor artesian basin. On the territory of this region, anhydrous boulder loams and clays of the Middle Quaternary age occur almost everywhere up to a depth of 10-20 m. Only in some places they contain a weak aquifer - groundwater, occasionally used through shaft wells.

Minerals

In the vicinity of the city, a complex was discovered and explored various kinds non-metallic minerals and solid fossil fuels. Non-metallic minerals are represented by raw materials for the production building materials- brick and expanded clay; glass and building sands. Brick clay as a building material in Rtishchevo is a common type of raw material. Building sands are widespread, half or more than half of which are suitable for concrete production. Deposits of building stone are small, only partially satisfying the needs of local construction.

Of the solid fossil fuels, there are peat deposits, but at present it is not being mined.

In general, the city of Rtishchevo is well provided with a mineral resource base of building materials, has promising deposits of mineral raw materials for agricultural and industrial purposes.

Students get acquainted with the features of the GP and the relief of Rtishchevo

Asking questions (proactive collaboration in seeking and collecting

information).

Independent work

And now let's complete a table of 2 columns in a notebook

Relief and minerals

Students complete the task in their notebook

highlighting and awareness by students of what has already been learned and what is still to be mastered, awareness of the quality and level of assimilation

Reflection

Execution of the detonation task:

P - something that relates to Rtishchevo

Students perform and discuss the results

Students' awareness of their learning activities, self-assessment of the results of their own and the whole class.

D / s.

Find literature in the library, analyze it according to the productive reading plan.

To use the preview of presentations, create a Google account (account) and sign in: https://accounts.google.com

Slides captions:

Relief and minerals of Africa Geography lesson, grade 7 Author: Olga Viktorovna Golovan, geography teacher Municipal educational institution "Lyceum No. 8 of the city of Budennovsk, Budennovsky district"

Goals and objectives: To form students' understanding of the tectonic structure, relief and minerals of Africa - their composition, structure, location. Continue the formation of the ability to establish cause-and-effect relationships, work with geographical maps and compare them.

Repetition of the material covered. What is the area of ​​Africa? (Second in the world) In how many hemispheres is Africa located? (In four) What is Almadi? (Cape) Which cape is the extreme southern point of Africa? (Needle) What is the closest continent to Africa? (Eurasia) What strait separates Africa from Europe? (Gibraltar) Northern Cape of Africa. Cape Almadi Cape Agulhas Strait of Gibraltar (Ben Secca) Cape Ben Secca

Repetition of the material covered. Specify the name of the traveler This Portuguese navigator discovered the sea route to India, rounding South Africa, passed along the eastern coast of the mainland, crossed the Indian Ocean and reached the shores of Hindustan. Vasco da Gama

Repetition of the material covered. Name a famous explorer. He crossed South Africa from west to east, explored the Zambezi River, discovered a large beautiful waterfall on it, which he called Victoria. Who led the expedition, which from 1926 to 1927. in Africa collected 6,000 specimens of cultivated plants? David Livingston Nikolay Ivanovich Vavilov

Map analysis: "The structure of the earth's crust." How many lithospheric plates is Africa on? Are there areas of collision with other plates? If so, where, and what processes occur during a collision? What is the name of the plate and platform on which the mainland is located? What age mountains are located on the mainland? In what direction and at what speed is the plate moving? (African plate, African platform) (On the same lithospheric plate) (African and Eurasian plates collide.) (Ancient mountains: Cape and Draconis; young mountains: Atlas) (Plate moving northeast)

Comparison of tectonic and physical maps. What is relief? How do you see the dependence of landforms on the structure of the earth's crust of the mainland? Recall the studied landforms. (The set of irregularities earth's surface, differing in size, origin and age, are called relief) (Plains are located on platforms, and mountains are in folding areas.)

East African faults What landforms prevail in Africa? What are the reasons for the diversity of relief? In East Africa, there is the largest fault in the earth's crust on land. It stretches along the Red Sea through the Ethiopian highlands to the mouth of the Zambezi River. What do you think about his education?

Relief Where are the young mountains? What are their names? Could young mountains form in the center of the Sahara? Where are the lowlands? How do you see the dependence of landforms on the structure of the earth's crust of the mainland?

RELIEF Plains occupy most of Africa. According to the prevailing heights, the mainland can be divided into Low Africa and High Africa. Determine on the map the prevailing heights of Low and High Africa.

Work with the physical map of Africa. n / n Name of the relief form Name of the highest point Absolute height of the point, m 1 Toubkal 4165 2 Ahkhagar Highlands Tahat 3 Ethiopian Highlands 4 5895 5 Darfur Plateau 6 Tibesti Highlands 3415 On the physical map of Africa, enter the missing data in the table.

Atlas Mountains In the north-west of the mainland are the Atlas Mountains, the northern young ranges of which are located at the junction of two lithospheric plates.

toubkal The highest peak of the Atlas is Mount Toubkal (4165 m), a favorite vacation spot for fans of ski tourism.

Mount Kilimanjaro Kilimanjaro is one of the largest extinct volcanoes in the world, the highest mountain in Africa.

Ethiopian Highlands The Ethiopian Highlands is a huge mountain range with chains of high mountains and many individual extinct volcanoes.

Dragon Mountains Dragon Mountains look like a ledge, one slope of which is gentle, and the other is steep, and the steep slope is half as long as the gentle one.

MINERALS. Which part of Africa is rich in igneous ore minerals, and which is rich in sedimentary minerals? What are the differences in the distribution of mineral deposits of different origins?

conclusion Minerals of sedimentary origin correspond to the plains, and these are the northern, western and central parts of the mainland. Minerals of igneous origin correspond to the mountainous relief, and these are the eastern and southeastern parts of the mainland. Consequently, there is a certain relationship between the structure of the earth's crust, relief and minerals, namely: the platforms correspond to plains and deposits of sedimentary minerals. Minerals of igneous origin are found on the plains, where the crystalline foundation of the platform comes close to the earth's surface, as well as along the fault line of the earth's crust. Folded areas correspond to mountains and minerals of igneous origin. Sedimentary minerals are found in the mountains, the formation of which took place on the site of an ancient sea.

Test 1. They are located at the junction of two lithospheric plates 1) Dragon Mountains; 2) Cape Mountains; 3) Atlas mountains; 2. The highest point in Africa 1) Mount Kilimanjaro; 2) volcano Kenya; 3) volcano Cameroon. 3. Huge reserves of 1) copper ores have been discovered in North Africa and on the coast of the Gulf of Guinea; 2) diamonds; 3) oil. 4. Highlands in East Africa 1) Ahaggar; 2) Ethiopian; 3) Tibesti. 5. Mountains in southeast Africa 1) Dragon Mountains; 2) Cape Mountains; 3) Atlas mountains; 1.3; 2.1; 3.3; 4.2; 5.1.

Homework §25. Mark on contour map large landforms and mineral deposits.

List of used sources Library of electronic visual aids "Geography 6-10 grades" Nikitin N.A. Lesson developments by geography. 7th grade. - M.: "VAKO", 2005 http://ru.wikipedia.org http://www.tonnel.ru/?l=gzl&uid http://geography7.wdfiles.com/local--files/surface-of -africa/Tizi%27n%27Toubkal.jpg http://geography7.wikidot.com/surface-of-africa http://sergeydolya.livejournal.com/354124.html http://commons.wikimedia.org/wiki/ http://upload.wikimedia.org/wikipedia/commons/thumb/4/47/Ethiopian_highlands_01_mod.jpg/640px-Ethiopian_highlands_01_mod.jpg?uselang=en

On the East European Plain, where the Leningrad Region is located, mountain building processes ended in ancient times. geological eras. Such areas of the earth's crust are called platforms. The basis for the East European Plain is the Russian platform, the foundation of which is composed of ancient crystalline rocks– diabases, gneisses, granites, diorites. Northwest of the Priozersk-Vyborg line, these crystalline rocks come to the surface. To the south, on crystalline rocks, lies a stratum of sedimentary rocks deposited in the seas that covered this territory for many millions of years. In the south and east of the region, the foundation is located at a considerable depth (800-1000 m). Sedimentary rocks on the territory of our region are represented by blue clays of the Cambrian age, occurring on granites; above are sands and sandstones, then limestones, as well as marls and dolomites of the Ordovician, Devonian and Carboniferous periods (it should be noted that this, of course, is only a simplified diagram of the geological structure).

A new period in sedimentation and relief formation in our region is associated with the activity of continental ice and melt waters during the ice age, and later with the activity of the sea, flowing waters, wind, and also people. The territory of the region has experienced several ice ages, which alternated with interglacial epochs. The last glaciation ended only 12 thousand years ago. The thickness of the glacier reached 2 km; ice with such a mass acquires the properties of plasticity, i.e. begins to flow, moving masses of loose material - moraine, tearing off huge pieces of underlying rocks along the way and dragging them over long distances. Thus, granite boulders can sometimes be found at a distance of many hundreds of kilometers from the places of natural occurrence of granites. Deposits of water flows and reservoirs that existed inside and on the surface of the glacier remained in the form of elongated ridges - Ozov and round hills Kamov. The glacial relief is characterized by a disorderly accumulation of hills composed of sand, rubble, boulders, which alternate with depressions, often occupied by lakes and swamps. Such a relief is especially characteristic of the Karelian Isthmus, the picturesque features of which are associated with the last glaciation.

On the territory of the Leningrad region there are hills.

Veps upland is located in the east of the region (the highest absolute height is 291 m in the region of the Gapselga ridge) and is part of the Valdai Upland.

Lembolovskie the heights are located in the central part of the Karelian Isthmus and represent a typical example of glacial relief - numerous moraine hills separated by a dense river network and shallow lakes; the highest absolute height is 205 m. A hilly-kame relief is widespread around this hill, most pronounced in the Kavgolovo and Toksovo regions.

Izhora Upland located south of the Gulf of Finland; its surface is flat, so sometimes you can find the name Izhora plateau. The Izhora Upland is composed of calcareous rocks - limestones, marls and dolomites; the most high point- 168 m. In the north, the hill is limited by a steep ledge, which is called

Baltic-Ladoga Glint(Glint is translated from Swedish and means "ledge"), up to 60 m high. This is the coast of the ancient sea, which, forming picturesque canyon-shaped valleys, is cut through by the rivers Tosna, Sablinka, Mga, etc. Its length from west to east from the city Tallinn is approximately 400 km.

A significant part of the region's area is occupied by lowlands and lowland plains. On the southern coast of the Gulf of Finland is located seaside lowland. From the south, it is bounded by a glint and consists of several terraces corresponding to different levels of near-glacial reservoirs in different periods. Wind-blown sandstones meet here. dunes; their relative height is 10-30 m, and the width in some places is more than 10 km.

Along the southern shore of Lake Ladoga stretches Ladoga lowland, which is part of a vast lake basin, with lake terraces and sand dunes, alternating with marshy depressions and deep valleys of rivers flowing to the lake.

Most of the territory located south of the Izhora Upland and west of the Veps Upland is occupied by the outskirts Priilmenskaya lowland; flat, heavily swampy areas predominate here, as well as moraine and sandy hills and hollows with lakes. In the valley of the Neva river is Prineva lowland.

There are mineral deposits on the territory of the region. In the area of ​​the city of Kingisepp, they mine phosphate rock used for the production of fertilizers. In the east of the region, not far from the city of Boksitogorsk, there is a deposit bauxite- raw materials for the production of aluminum. In the west, near the city of Slantsy, mining is carried out oil shale, which are used as fuels, lubricating oils and chemical raw materials (for the production of plastics, medicines, etc.). On the Karelian Isthmus near Vyborg and near Priozersk, beautiful and durable crystalline rocks are mined - granites, gneisses, gabbro, quartzites, used for decorative finishing of buildings, facing embankments, making pedestals for monuments and the monuments themselves. Thanks to them, St. Petersburg acquired its "strict, slender appearance." Recall that both the Alexander Column and the columns of St. Isaac's Cathedral are made of granite. Clays, sands and limestones are mined in the pre-glint lowlands, on the Izhora Upland, on the hilly plains in the south and east. Blue Cambrian clays are used for the production of bricks, ceramic products, as well as in the production of porcelain (now also widely used in medicine and perfumery). Limestones, formed from the remains of the marine fauna of the ancient seas of the Ordovician period, are used in construction. Near the village of Pudost on the Izhora Upland there is a unique deposit " Pudozh stone " - limestone dissolved by underground waters and then carried out and redeposited by springs. When mined, it is so soft that it can be cut with a knife, but after a while it hardens and becomes very strong. Now it is used only for restoration work. Statues near the Rostral columns, the columns of the Kazan Cathedral were made of this stone, and it was also widely used in the restoration of the palace of Paul I in Gatchina. Dolomites(a type of limestone) are used as a raw material for the production of cement. In the south of the region, in the Oredezh River basin, sands- construction, molding, glass (deposits of quartz glass sands are mainly located in the Luga River basin). In addition, the following are mined in the Leningrad Region: peat- more than 2 thousand deposits, mainly in the east of the region - used as fuel, bedding for livestock, fertilizer, sapropels(silts, which are unique additives to soils to increase fertility, which are mined in 125 lakes) , mineral paints, mineral waters.

Of particular note is another very valuable mineral. Our region has huge reserves fresh water Very good quality in ecological terms. This circumstance is extremely important in the light of the ever worsening environmental situation on the globe and associated scarcity of fresh water in many regions of the world.

Climate

The climate of the region is characterized as transitional from continental to maritime, while continentality increases from the west of the region to the east and northeast: the average annual air temperature in St. Petersburg is +4.1◦С, in the western part of the Leningrad region +4.5◦С , in the north of the Karelian Isthmus +3◦, and in the north-east of the region +2.2◦С.

From the west, from the side Atlantic Ocean, humid sea air of temperate latitudes enters the territory of the region. In winter it is warm, causing thaws and sleet. In summer, the arrival of this air causes rain and cool weather.

The entire territory of our region is located in the zone of excessive moisture. The average annual amount of precipitation, which is 550-650 mm, by 200-250 mm more quantity evaporating moisture. This contributes to the waterlogging of the soil. Relative humidity is always high (from 60% in summer to 85% in winter).

A very important feature of the circulation of air masses in our region is the emergence, movement and evolution of large-scale eddies - cyclones and anticyclones, as well as the formation of atmospheric fronts due to the contact of air masses with different meteorological characteristics.

From the west, from the Baltic Sea, air masses bring us rain, fog, and surge waves that sometimes raise the water level in the Neva to catastrophic levels. Cyclones crossing the Baltic Sea from the southwest to the northeast form a special kind of long wave. Its height is small - 30-40 cm, and the length is comparable to the length of the sea. Swelling of water occurs in the throat of a narrow bay. The advance of the wave is almost always accompanied by a westerly wind, bringing a series of cyclones. Then the flood is inevitable. If we take into account the full flow of the Neva, then one can imagine how many troubles the movement of a huge mass of water at a speed of 100 km per hour can bring. It is estimated that during the catastrophic flood of 1924, 27 cubic kilometers of water moved eastward in 6 hours of water level rise. This amount of Don takes out to the Sea of ​​Azov for a year and a half. Sometimes floods can occur with light winds and even during calm. This means that somewhere in the vastness of the Baltic a long wave passed.

Since the birth of our city, there has been a struggle with the water element - coastal areas were washed, embankments were raised, the banks of the Neva were strengthened. The bypass canal was built specifically for the purpose of diverting water during floods, although the canal did not fulfill its role, because during its construction the nature of the floods in the Neva was not yet very well studied. Currently, a dam is being built to block the Neva Bay between the village of Gorskaya on the Karelian Isthmus and Lomonosov. A ring freeway will pass along the dam, which should have a positive impact on the city's ecology.

High cloudiness (total 75 sunny days per year!), high humidity, moderately warm winters and cool summers are all signs of a maritime climate.

Winter according to the classical scheme is usually snowy, in the first half it is moderately cold, with thaws, and in the second half the weather becomes more frosty. The average monthly temperature in St. Petersburg drops from -4◦С in December to -7◦С in January-February (from -8◦С to -11◦С in the east of the region). Anomalies in the weather should be noted (associated, it is believed, with the general warming of the climate on the globe) recent years- deviations in one direction or another of the average temperatures of summer or winter; but unusual winters and summer periods noted in previous years. Unusually cold, for example, was the blockade winter of 1941-1942. – the average temperature for January was -18.7◦С (12◦ lower than usual); in 1924 the average January temperature was only -1.3°C, and the Neva did not freeze.

Spring begins in mid to late March; it develops slowly, the weather is quite stable and the number of days with precipitation is small. Often, Arctic air masses invade the region, and cold snaps are associated with them, sometimes in the form of frosts.

The arrival of summer in our region is marked by the onset of "white nights"; this phenomenon is associated with the latitudinal position of our region. Summers are moderately warm, although recent decades in summer, abnormally hot weather was observed in some years.

At the beginning of autumn there is a short favorable period windless and even warm weather, which is called "Indian summer". From October, the temperature drops rapidly, cyclones intensify, cloudy, cool, windy weather with drizzling rain and fog prevails, which persists into November.