22/07/2020

Quite a different picture in the east of Western Svalbard.

Quite a different picture in the east of Western Svalbard.

Cochlear tastes like a salad, and it is widely eaten by the inhabitants of the archipelago. A little later, yarrow, forget-me-nots, hellebore, yellow foxglove, polar poppy, purple Svalbard carnations bloom. The leaves bloom on the dwarf shore and polar willow.

Quite a different picture in the east of Western Svalbard. Here along the coast is a cold current. Only on the southern slopes in the "hottest" months small spots of moss turn green and polar poppies bloom.

With the onset of spring, the air is filled with bird voices. There are many bird markets in the archipelago. On the coastal rocks nest lyuriks, chistuny, kaira, sea gulls, three-legged martins, fulmars, dead ends, wild ducks, swans, geese and other birds, including the big and predatory gull "burgomaster".

The fauna of the archipelago is not rich. Huge herds of deer used to live on the islands. At the end of the 19th century. hunting this beast was a "fashionable" sport. Now the deer are almost completely destroyed. Occasionally the islands are visited by the "master of ice" – a polar bear. Blue foxes are also found in the archipelago. Of the mammals, many seals and hares. In the waters that wash the western part of Western Svalbard, there are many cod and flounder fish.

The main wealth of the archipelago is high-quality coal. It is mined in a number of mines – Barentsburg, Grümantbuen.

11/26/2011

River network of Africa. Abstract

Inland waters of Africa. Congo river

Inland waters of Africa

Climatic features and the nature of the relief of Africa determine the distribution of runoff and hydrological regime of rivers. Almost 80% of precipitation evaporates and only 20% forms runoff (5,400 km3 per year) – more only in Eurasia and South America. Areas that do not have ocean runoff account for 31% of the continent.

Africa’s main watershed is in the east, where the highest elevations are located. Due to the general tilt of Africa to the west, the highest runoff rates are in the Atlantic basin and the lowest in the Mediterranean basin, despite the fact that one of the world’s largest rivers, the Nile, carries its waters here.

The formation and development of the modern river network of Africa took place from the end of the Neogene, when climatic conditions became close to modern. For a long time, the mainland was mainly an area of ​​internal runoff. The formation of external runoff was facilitated by the raising of large areas of the platform in the east of the mainland.

Erosion of plateau slopes and plateaus facing the ocean has led to the formation of new river systems. They intercepted the runoff of those rivers that arose earlier. Therefore, modern rivers of Africa are characterized by alternation of long segments of long, long valleys with a large number of terraces and young profiles with narrow valleys, rapids and waterfalls (lower Congo, Zambezi, Orange, etc.). As a result, Africa’s rivers are often unsuitable for navigation, but have significant reserves of hydropower.

In Africa, rainy food predominates. In arid areas, underground power supply is important.

According to the hydrological regime of the mainland rivers belong to the following types:

a) constantly flooded rivers of the equatorial belt with spring-summer floods (Congo basin); b) constantly multi-water rivers in areas of tropical humid climate with a summer maximum of rising water levels (Rufiji, Ruvuma, Limpopo, etc.); c) rivers of the subequatorial belt with summer-autumn floods and spring-winter boundaries (Senegal, etc https://123helpme.me/write-my-lab-report/.); d) rivers of the subtropical zone with winter floods and summer boundaries (Cebu, Muluya flowing from the Atlas Mountains and rivers flowing into the ocean from the Cape Mountains); e) rivers of tropical deserts, which feed mainly on groundwater, are often dry channels (wadi) and do not drain every year; e) rivers of extensive uplifts with mixed rain-glacial supply, floods in summer and surveys in winter (rivers of the East African plateau); g) rivers of the highest massifs of young mountains with mixed rain-snow supply and winter-spring floods (rivers of the Atlas, Cape and Dragon Mountains).

The water regime of large rivers is due to the regimes of their tributaries, so they are characterized by complex hydrological regimes. As a rule, these rivers flow through several climatic zones, so their regime is complex and often unpredictable.

The lakes of Africa are unevenly distributed. The largest of these are located in the ancient Zambezi River Valley of East Africa, where they are housed in grabens and are classic lakes of tectonic origin.

Groundwater is important in arid areas of Africa. In the Sahara, they are confined mainly to the continental sandstones of the Lower Cretaceous – they are often fresh or slightly mineralized. In South Africa, groundwater accumulates. as a rule, in fractures of native rocks and in karstic limestones. On the mainland, in general, there is a shortage of water almost everywhere, except for the Congo Basin. Therefore, there are great difficulties with water supply, irrigation and flooding. In addition, the problem of water pollution and depletion is very acute in Africa.

Congo river

The Congo is a large river on the African continent and one of the largest rivers in the world. In length – 4320 km – it is second only to the Nile in Africa, and in the area of ​​the basin – 3690 km2 – and the aquifer ranks first in Africa and second in the world, second only to the Amazon.

The Congo Basin, located at an average altitude of 400 m above sea level, has the shape of a bowl. To the north, it is separated from the Nile and Shari basins by the Azande watershed; mountain ranges up to 3000 m high limit it to the east of the rivers of the East African plateau; the Lunda-Katanga watershed separates it from the Zambezi and Kubango basins; from the west over the inner basin of the basin – the bottom of a huge bowl – rises the South Guinea Plateau.

The Congo has two main sources – Luapula and Lualaba. Luapula, called Chembeshi, begins south of Lake Tanganyika at an altitude of 2,000 m, flows through the shallow lake of Bangweulu, almost overgrown with reeds and papyrus, and then gets the name Luapula. Luapula turns north and flows through another shallow lake, Mwera, then merges with the flooded Lualaba.

Lualaba originates in the Lunda-Katanga watershed near the source of the Zambezi and is considered by many researchers to be the main source of the Congo. Its right tributary – the river Lukuga flows from Lake Tanganyika, which, in turn, receives the waters of Lake Kivu. Thus, these lakes in East Africa belong to the Congo Basin. During periods when the water level in Lake Tanganyika decreases, Lukuga almost dries up and runoff from the lakes in the Congo stops. Meanwhile, Lualaba is already a powerful stream, reaching 600 m wide and 11 m deep.

On the other side of the equator, the river descends from a steep marginal ledge into the central basin of the seven Stanley Falls from a height of 42 meters and below the waterfalls is called the Congo.

Behind the waterfalls begins the middle course of the river, which covers almost the entire huge bend, which gives such a bizarre look to the image of the Congo on maps. Here, the river, which flows slowly among the thickets of the equatorial forest, becomes very wide and bypasses numerous islands. Near the farthest northern point of the current, its shores are 5.5 km apart, while the average longitudinal profile is only 10 cm per 1 km. In the western part of the Congo Basin flows among wide and impassable swamps, but at the end of the middle course, before entering the mountains, the area becomes drier and the width of the river decreases to 500 cm.

All significant tributaries of the Congo receive in the middle course, and all of them, falling from the edges of the basin, in their upper reaches have rapids. The largest right tributaries of the river are the Aruvim, the vast Ubangi and the Sanga, but the left tributaries in the Congo are larger than the right. Among them are the long and multi-water Lomami and Ruki, as well as Kwa, which collects the waters of Sankuru and Kasai. Below the confluence of the Kwa Congo, it expands into the Stanley-Poole lake-like reservoir covered with numerous islands with an area of ​​555 km2 and a depth of up to 25 m.

The Congo breaks through to the coast through the South Guinea Plateau through a beautiful canyon rich in waterfalls and rapids. At the same time in a section of 350 km the decline of the longitudinal profile of the channel is 270 m. Stanley very accurately described this part of the river: "Roaring and foaming, the water falls steeply down.

Thresholds and huge walls of rocks that block its path, drive a crooked channel into deep gorges, breaking out of which it again, forming high waterfalls and rapids, falls huge ledges lower and lower. "This part of the river can not be used for navigation, and therefore between Matadi, a downstream port where ocean-going vessels enter, and the city of Kinshasa, a railway has been laid along the other rapids along the river.

After leaving the canyon begins a relatively short, dotted with islands, the lower reaches. The river overflows here in places up to 1.5 km, the depth of the powerful flow reaches 40-70 m. From Boma begins the estuary of the Congo, which continues along the ocean floor underwater valley for another 150 km.

The area of ​​the basin is from 1000 to 2000 mm of precipitation. In the central basin, in the equatorial latitudes of the basin, they are distributed evenly throughout the year, and on its northern and southern outskirts fall in the summer. The abundance of rain causes a powerful runoff of the Congo: on average, every second the river releases 39 km3 of water into the ocean, and the average annual runoff reaches 1230 km3. This figure is huge, but we must not forget that the flow of the Amazon is even greater – 3800 km3.

The position of the Congo Basin in both hemispheres causes a uniformly strong runoff throughout the year, but the northern tributaries bring less water to the river than the southern ones, because most (two thirds) of the branched river system lies south of the equator.

literature

1. Giletsky JR, Bogovich MM, Slyvka RR Geography. Universal guide for graduates and entrants. – Lviv: VNTL-Classics, 2003. – P. 89-91.

2. Zastavetskaya OV, Kuzyshyn AV Geography for entrants. Handbook for students of the faculty of pre-university training. – Ternopil, 2006. – P. 91-92.

3. Pestushko VY, Sasykhov VO, Uvarova GE Geography of continents and oceans. Ed. for 7 classes. among. school / K .: Abris, 1999. – S. 123-126.

11/26/2011

Climatic conditions of North America. Abstract

North America stretches from north to south for 7,000 km and is therefore located in all latitudinal climatic zones of the Northern Hemisphere, except the equatorial.