In some years, icebergs reached a latitude of 39°50". The same picture is observed in longitude. So, if east of the island of Newfoundland at a longitude of 60° the average annual number of icebergs is taken as 100%, then at a longitude of 58° it will be 96%, at 56° - 90%, at 54° - 60%, at 52° - 36%, at 50° - 22%, at 48° - 6% and at 46° - 1%. The number of icebergs in the Newfoundland area (48° N). . w) from year to year significantly m

decreases (from 10 in 1924 to 1351 in 1929), but on average it is 400. The largest number occurs in May, the smallest in November-December (Fig. 1.5). In other words, about 80% of icebergs cross the 48th parallel in April - July.

Figure 1.5 - Seasonal changes number of icebergs (N) south of Newfoundland

In the waters northern hemisphere From the point of view of the possibilities of ice navigation, five fundamentally different zones can be distinguished:

central part of Northern Arctic Ocean, where ice persists throughout the year;

seas of the Arctic Ocean (except for the southern part of the Barents Sea), bays and straits of the Canadian Arctic Archipelago, waters off the southeastern coast of Greenland - these areas are cleared of ice, but not annually or not completely; ice can be found here in some years in the summer ;

southeastern regions of the Barents Sea, White Sea, northern regions The Japanese, Okhotsk, Bering, Caspian seas, Davis Strait, Hudson and St. Lawrence bays - ice forms here every winter, but completely disappears in the summer;

open areas Baltic Sea, southern part the North Sea, certain waters of the Barents Sea, the northern part of the Yellow Sea, waters off the coasts of the Middle and Southern Caspian Sea, the Sea of ​​Azov and the northwestern part of the Black Sea - in these areas ice does not form annually, sometimes once every 25 - 30 winters;

waters of the North Atlantic north of the 40° parallel and west of the 45° meridian, where icebergs can be found.

In the first zone (only in certain areas), active navigation was carried out only by icebreakers. In the second zone, with the exception of the southwestern part Kara Sea, ice navigation is mainly carried out under the guidance of icebreakers in the summer. In the third zone, ice navigation takes place only in winter, and a significant part of the time without icebreaker support; in the fourth zone - only in some years and in most cases without icebreaker support. In the fifth zone, ships always sail independently, but at the same time, navigators are required to exercise extreme caution, because encounters with icebergs can result in serious disasters.

1.3 Ice of the southern hemisphere

The distribution of ice in the oceans of the southern hemisphere is fundamentally different. There is no asymmetry in the distribution of ice in the eastern and west coasts oceans. The ice of the southern hemisphere, encircling Antarctica throughout its entire length, is oriented mainly in the latitudinal direction at any time of the year with its outer edge (Fig. 1.6). This is mainly due to the presence of the Antarctic Coastal Current off the coast of Antarctica western direction, formed under the influence of eastern winds. In some areas, the Antarctic current is interrupted by a number of cyclonic circulations that develop as a result of stationary atmospheric depressions in the coastal areas of Antarctica - the Weddell, Lazarev, Riiser-Larsen, Cosmonauts, Commonwealth seas, the southwestern part of the Ross Sea, the northern part of the Amundsen Sea, the northeastern part of the sea Bellingshausen area of ​​the Balleny Islands.

Figure 1.6 - Distribution of sea ice in the southern hemisphere

The presence of cyclonic circulations has a significant impact on the formation of ice conditions in the Antarctic: it promotes the removal of ice, the formation of polynyas in some areas and the formation of ice massifs in others (Fig. 1.7).

Overall for Antarctic ice a general outflow drift is characteristic, i.e. ice drift from the coast. Drifting to the northern, warmer regions of the ocean, the ice is rapidly melting. That is why in Antarctica one can find mainly first-year and young ice; only rarely in certain areas where stable ice masses are formed can one find two-year-old and multi-year ice. The largest massifs are located in the waters of West Antarctica: the Atlantic Massif in the Weddell Sea and the Pacific Massif in the Bellingshausen and Amundsen Seas. During the summer season, these areas experience the greatest amount of ice.

Education young ice begins in West Antarctica in the second half of January, in early March - in East Antarctica. The growth of young ice occurs very intensively, and ice formation quickly spreads to the north.

Ice occupies the largest area in Antarctica in September, when the maximum width of the drifting ice belt is 1200 miles (Weddell Sea), the minimum is 300 miles (Drake Passage).

During the winter, fast ice is established in the coastal zone of Antarctica, the prevailing width of which is 15 - 25 miles, varying from 1 to 50 miles. In October-November, fast ice reaches its maximum thickness - 120-200 cm.

Cracks form on Antarctic fast ice, the width of which varies from several centimeters to several meters.

1 - ice concentration, points; 2 - fast ice; 3 – polynyas

Figure 1.7 Typical ice conditions in Antarctic waters in the summer.

Antarctic waters are dominated by ice, the horizontal extent of which does not exceed 100 m, which is explained by the impact of wind waves and swell on the ice. Extensive fields, stretching up to 10 miles, are only occasionally found in the Atlantic and Pacific massifs, the western part of the Ballen massif. The processes of ice hummocking in the Antarctic are weakly expressed, since outflow ice drift predominates here. For the same reason, the thickness of flat first-year ice by the end of winter averages about 140 cm.

The safety of ships in Antarctic waters depends on the distribution of icebergs, which form almost throughout ice continent as a result of calving of the marginal sections of the cover outlet and shelf glaciers. According to experts, the annual "production" Antarctic glaciers is 17.8 - 1017 g, i.e. approximately 4 times more than in the Arctic. The limit of the maximum distribution of icebergs to the north approximately coincides with the front of the so-called Antarctic convergence - a strip of convergence and mixing of Antarctic and subtropical water masses. The convergence boundary in the Indian Ocean sector is located at latitude 48 - 53°, Pacific Ocean- at latitude 53 - 62°, Atlantic - at latitude 47 - 58° (see Fig. 1.6).

During the cold season, ice covers more than 15% of the surface of the World Ocean. By the end of winter, the boundaries of the distribution of floating ice shift to lower latitudes, and by the end of summer - to wider latitudes.

For Atlantic oceans are characterized by sea and glacier floating ice(icebergs). In the northern part of the ocean, they are found annually in the area of ​​Greenland and south of the Newfoundland Banks. As it drifts south to 40°N. icebergs are destroyed. Sea ice is melting before reaching this parallel.

IN Quiet In the ocean, floating and glacier ice are less common than in the Atlantic. Icebergs are found here only in the Gulf of Alaska and in the southern ocean, breaking off from the glaciers of Antarctica. Fast ice is observed from December to April in the bays and bays of the eastern coast of Kamchatka. In open parts of the seas, ice drifts south.

Northern-Arctic In winter, the ocean is completely covered with ice, 2.5–3.0 m thick. Icebergs are rare here.

In the summer, intensive ice melting occurs, but it does not ensure the destruction of all the ice formed during the winter. Huge masses of ice are carried by the East Greenland Current into Atlantic Ocean. There can be up to 40,000 icebergs of varying sizes in the Baffin Sea at any one time.

The probability of encountering icebergs over 100 m in length in the coastal zone is 20%, over 300 m - 5%. In the open ocean north of 65°S. icebergs longer than 1500 m are rare.

Black the sea freezes only on the northern shores. The Dnieper-Bug estuary and the Dniester estuary freeze completely. In Crimea, ice forms only in closed bays.

Azovskoe the sea freezes along all coasts in the form of wide fast ice, the central part is free of ice or filled with drifting ice.

7. Navigation aids on ice

Navigation aids, which contain detailed information about the ice regime and conditions of a particular area of ​​the World Ocean, include:

• atlases of physical and geographical data.

  ice atlases,

  albums of ice formations on the seas.

Destinations. In the section “Hydrometeorological outline” the directions are described:

general information about ice conditions,

timing of the appearance and clearing of ice in certain areas,

main types and forms of floating ice, their thickness and direction of drift,

coastal areas where fast ice occurs,

diagrams of ice distribution boundaries.

Atlases of physical and geographical data. They present the average, minimum and maximum values ​​of the ice regime, contain monthly maps of ice distribution, on which areas of iceberg distribution can be highlighted and the probability of encountering them can be shown, etc.

Ice atlases - These are special Ice Atlases, which contain the most detailed information about the ice of any sea. It is specially designed to ensure navigation safety in winter.

Albums of ice formations on the seas . In these albums:

photographs of existing types and forms of sea ice are included,

explanations of ice terms related to the presence of ice in the sea are given,

the processes of formation and melting of sea ice are described,

diagrams of the main types and forms of ice found in the sea are included

classification and terminology of sea ice and phenomena associated with it are given.

The album contains a number of applications that help you better understand the ice conditions at sea. Such albums can be used by navigators to identify types and forms of ice and compile operational ice maps and reports.

3.5 Ice maps

Ice maps are issued by many countries: Canada, USA, Great Britain, Sweden, Russia, etc. Each country uses its own symbols to describe ice, however, international symbols have also been developed for sea ice maps.

The passability of ice depends on the properties of the ice, its concentration, design features and technical condition of the vessel. Depending on the concentration, ice permeability is assessed as follows:

Cohesion up to 4 points - ice is passable for all vessels, speed loss is less than 25%;

Broken ice and fields more than 4 points - independent navigation of vessels with conventional hulls is difficult;

Small broken ice 8 points, coarse ice 6 points - independent navigation of ships with reinforced ice hulls is difficult.

The speed of ships is significantly affected by ice compression. Compression can be taken into account in two ways:

By multiplying the technical ice speed of the vessel in compacted ice by the corresponding speed reduction factor at different compression forces;

By extrapolating the ship's speed in compact ice, assuming that each compression point corresponds to an increase in ice concentration by 2 points over 10.

The condition of the ice also affects its passability. Ice hummockiness leads to an increase in its average thickness. The destruction of ice causes a decrease in its strength characteristics and can be taken into account by reducing its thickness.

Icebergs: formation, distribution, danger and methods of protection,

prospects for use

Saint Petersburg,

1.General information………………………………………3

2. Glaciology……………………………………………………..5

3. Danger and methods of protection…………………………….....6

4. Use………………………………………………………....8

5. Literature……………………………………………………9

General information

Iceberg is an ice mountain, a large block of glacial ice floating or grounded in an ocean, sea or periglacial lake. It is formed due to the breaking off (under the influence of hydrostatic water pressure, tides, currents and wind) of the ends of glaciers descending into the water. The main centers of iceberg formation, which produce the largest number and largest specimens, are ice shelves (ice shelves - partly lying on the shelf, partly on the water) of Antarctica and the northern islands of the Canadian Arctic Archipelago, as well as the glaciers of Greenland. Depending on the density of ice and water, from 83 to 90% of the volume of icebergs is under water. Icebergs rise above the water surface by an average of 70 m (Arctic) - 100 m (Antarctic). Under the influence of uneven melting, icebergs capsize from time to time. Greenland icebergs are carried by the East Greenland and Labrador currents up to 40-50° northern latitude, V in some cases- to the south; Antarctic icebergs reach 45-60° south latitude, in 1894 they were observed even at 26° south latitude, i.e. tropical zone. The direction of iceberg drift depends mainly on ocean currents, so icebergs often move against the wind.

Antarctic icebergs rarely travel far north into the Indian Ocean and South Pacific, where major shipping lanes lie, although they have been encountered as far as 160 km south of Australia. IN South Atlantic icebergs drift with the Falkland Current from Cape Horn to Cape Good Hope. Northern part The Pacific Ocean is separated from the Arctic Ocean (except for the narrow Bering Strait) and is free of icebergs. 10-15 thousand icebergs break off from the West Greenland glaciers every year, many of them coming from East Greenland and the northeastern Arctic coast of Canada. The Labrador Current carries these icebergs south along Newfoundland, and then the Gulf Stream carries them across the Atlantic in a north-northeast direction. From April to August, icebergs are abundant along busy North Atlantic shipping lines and can be seen year-round in areas north of 43°N latitude. Sometimes in the south they were found up to the latitude of the Azores.

Sometimes floating ice mountains resemble medieval castles or watchtowers in their outlines. They are called pyramidal. There are also table-shaped icebergs - their tops look like large flat fields.

Antarctic icebergs float on huge territory cold south seas, not constrained by continental borders, sometimes rise to southern coasts Africa and Australia. The shape of these icebergs has its own characteristics: often they are so-called table-shaped icebergs - flat ice fields that rise slightly above the water. Being fragments of shelf ice, they have brackish lower layers, but their bulk is pure fresh ice. They cover the surface of the Arctic islands and the Antarctic continent and gradually slide into selected places to the ocean. Sometimes such ice cover spreads over the surface of the sea, forming so-called coastal glaciers. From them, from time to time, large table-shaped ice fields break off, which, under the influence of winds and currents, set off to wander across the oceanic expanses, becoming “sea vagabonds.”

Pyramid icebergs are born in glaciers descending from the mountains to the ocean. An unforgettable sight is the moment when a giant block breaks off from such a glacier hanging over the sea. The iceberg is born under a booming roar reminiscent of gunfire. In Greenland there is the famous Jakobshavn glacier, from which people go far away every year. sea ​​travel tens of millions cubic meters icy mountains There are many such glaciers on the shores of Novaya Zemlya, Alaska, and Spitsbergen.

The largest Antarctic iceberg is considered to be one discovered by researchers in 1964. Formed after the break of the Emery and Western ice shelves, this giant reached 175 km in length and 75 km in width, and its area was 12 thousand square meters. km. Icebergs like this one rise hundreds of meters above the water. And since approximately 6/7 of their height is hidden under water, they are carried by a subsurface current, the direction of which does not always coincide with the surface one. Therefore, icebergs often change course, which increases the risk of colliding with them.

During long-term drift, entire systems of through gullies often form in icebergs. Such icebergs are called singing icebergs: in windy weather they suddenly make fantastic sounds.

The ability to generate sounds has also been found in ice that does not have noticeable cavities. Polar ice in a tense state sounds polyphonic, like a huge organ. The nature of the sound of ice depends on the ambient temperature, but the nature of this phenomenon still remains a mystery. Even at the beginning of this century, icebergs were seen only as a threat, but now people are beginning to actively use them for various purposes. The main goal is to use these giant ice “cans” as sources of water supply.

This is especially important for the waterless coasts of the Australian and South American continents, relatively close to the Antarctic basin. Of course, long-distance transportation of icebergs is a complex and unusual matter. There are also many difficulties associated with getting icebergs to melt in the required manner. However, according to preliminary calculations, the cost of melt water from towed icebergs is still much lower than desalinated sea water. In addition, this water is immediately drinkable.

And one more thing unexpected property icebergs and perennial strata continental ice scientists discovered. It turned out that these are the ideal “memory storerooms” of our planet. Due to circulation air masses tiny particles airborne impurities are deposited everywhere on earth's surface, but practically nowhere, except for ice massifs, are they inaccessible to subsequent observation. In Antarctica, the ice has been growing for many millennia and now its thickness reaches about four and a half kilometers. Here the earthly and cosmic dust, volcanic ash, microorganisms and even the air of bygone times. All this allows us to understand the process natural processes, to know the distant past of our planet. Scientists are studying more and more deeply the “memory” of the Earth’s ice sheets, comprehending its significance for understanding the planetary phenomena of climate stability, processes of energy redistribution on Earth, etc. Although the ice monoliths do not form a continuous layer, they are beginning to be separated into a separate sphere - the glaciosphere, along with the atmosphere, hydrosphere and lithosphere. The planet's ice, constituting a tenth of its surface, is one of essential components the surrounding world.

How do icebergs melt?

They are destroyed differently in the places where they are formed and in the places where they are carried out. In areas of powerful ocean currents - the Lambardora and Gulf Stream - they have been studied most thoroughly. In the Labrador Current, in summer the water is cold, and the air above the sea is warm. Consequently, melting begins from the upper, above-water part. In the Gulf Stream, the water in the spring is much warmer than the air and the iceberg melts, first of all, from below in the underwater part. In the summer in the Gulf Stream, both the water and the air are warm and the icebergs melt quickly, like streams running from the mountains on land, large and small pieces break off, the iceberg loses its balance and turns over. It has been noticed that the height of the iceberg decreases per day, sometimes by more than 3 m; saw an iceberg that became 10 m lower in one day. Typically, an iceberg moves from the Baffin Sea to the area south of the Great Newfoundland Bank for about five months. During this time, its height is halved, and total mass-- 10 times.

When the sea is rough, icebergs are destroyed mechanical forces, mainly waves. Now the erosion is concentrated not in the surface or underwater part of the ice mountain, but in the part closest to the surface of the water. This is where the saddle shapes of icebergs and ice floes come from.

Moving to more warm waters, the iceberg melts from below, as a result of which its center of gravity moves above the center to which the buoyant action of water is applied. Such an iceberg loses its balance and capsizes noisily.

When the sea is calm and there is no wind, the iceberg with its melted lower part begins to sway, which is a sign of an impending capsize. When the iceberg is in a state unstable equilibrium, even the operation of the machinery of a nearby ship can give an impetus to capsize.

Melting icebergs on the southern border northern seas causes a slight decrease in water salinity. In the same area, during the melting process, icebergs drop the parts of moraines they have captured, and sometimes quite large pieces of rocks, to the bottom of the seas.

In the middle lane Soviet Union There are traces of similar iceberg activity dating back to the period when the territory of our country was the bottom of the sea. Similarly, the removal of rounded pebbles to the bottom of the Arctic basin occurs. Freezing to the ice near the coast, the pebbles, along with the ice floes, are subsequently carried into the ocean and sink to its bottom after the ice melts.

Glaciology

Glaciology (from Latin glacies - ice) is the science of the ways of ice formation, its evolution and diversity. About the forms of ice on the earth's surface (glaciers, snow cover, ice caves, etc.), underground ice, floating ice (icebergs), their structure, composition, physical properties, origin and development, geological and geomorphological activity, geographical distribution.

The task of Glaciology (in this sense of the word) includes the study of the conditions and characteristics of the origin, existence and development of glaciers, the study of their composition, structure and physical properties, geological and geomorphological activity and various aspects interactions with the geographic environment. Glaciology is closely related to physics and mechanics and widely uses their methods along with the methods of geological and geographical sciences, to the cycle of which it belongs.

Glaciology as a science about glaciers was started by the Swiss naturalist O. Saussure with his essay “Journey to the Alps” (1779-96). In the 19th century A general range of ice problems emerged, but there was a lack of systematic materials on glaciers, research methods were primitive, and knowledge about the physics of ice was insufficient. Therefore, the first stage of the development of glaciology was predominantly descriptive and was characterized by the accumulation of information mainly about the forms of glaciation in temperate countries. Many patterns of mountain glaciation did not always reasonably apply to all other types of glaciers.

The works of L. Agassiz, D. Forbes, J. Tyndall, F. Forel, S. Finsterwalder, A. Geim, R. Klebelsberg, H. Reid and others abroad and the research of N. A. Bush were of great importance for the development of glaciology , V.I. Lipsky, V.F. Oshanin, K.I. Podozersky, V.V. Sapozhnikov, B.A. Fedchenko, P.A. Kropotkin and others in Russia, where the study of glaciers was carried out from the 2nd half of the 19th century mainly on the initiative of the Russian Geographical Society (the so-called Glacier Commission was created here under the leadership of I.V. Mushketov). The practical significance of Glaciology is due to the wide distribution of glaciers on Earth (about 11% of the land) and the fact that large number fresh water(27-29 million km3) is contained in glaciers. The study of glaciation allows for more rational use water resources rivers originating in glaciers, prevent disasters associated with the life of glaciers (mudflows, floods, etc.), take into account economically suitable areas released due to fluctuations of glaciers, etc.

Created special institutions to study ice and glaciers in the USSR, Switzerland, USA, Canada, Italy, France, Great Britain, Japan, Argentina, etc. In 1894, the International Glacier Commission was organized (now the Snow and Ice Commission of the Association for Scientific Hydrology International Union geodesy and geophysics).

Danger and methods of protection

Iceberg literally means “ice mountain”. And this is no exaggeration. Ice giants tens and even hundreds of kilometers long are found in the oceans. In 1927, the Norwegians met a giant whose length reached one hundred and seventy kilometers.

Icebergs are very dangerous. After all, even a modern ocean liner is a toy compared to such a huge floating block of ice. True, now sailors already have the opportunity to avoid a collision: modern navigation instruments, in particular radars, allow them to see in any meteorological conditions. But the history of navigation knows more than one tragedy associated with collisions with icebergs. So, a few years ago, a disaster occurred with the Danish steamer Hans Hedtoft, killing ninety-five people. At the same time, in Newfoundland waters, off the coast of America, they were damaged by floating blocks of ice. soviet ships"Chernyshevsky", "Radishchev" and "Noginsk".

In 1854, sailors more than once encountered a table-shaped iceberg one hundred twenty kilometers long and ninety meters high. It was calculated that its volume reached five hundred cubic kilometers. Over the course of ten years, twenty-one ships reported the progress of this giant towards the equator. And in 1904, the Zenit ship encountered a pyramidal iceberg four hundred and fifty meters high near the Falkland Islands.

Dangerous ice mountains wander the seas and oceans for many months and years. It is believed that their age can reach ten years, unless, of course, currents carry the iceberg into warm waters. Gradually, wind and fog, waves and warm air destroy the iceberg - it melts, shrinks, and breaks into pieces. But individual fragments of ice mountains, or rather, no longer fragments, but rounded ice floes smoothed by waves weighing several tons - sailors call them “nuts” - become even more dangerous than large mountains of ice. An iceberg is clearly visible on the radar screen, but such a “nut” goes unnoticed and therefore can cause a disaster.

In 1954, on one of the stormy nights, the whaling ship Slava-5 collided with such a “nut” and received a hole. Only the courage of the crew saved the ship from destruction.

In clear weather, thanks to their shiny surface, icebergs are visible from afar. At night, breakers form a warning sign white line around their base. In fog they are poorly distinguishable at a distance of over 90 m, and before the invention of radar they were detected using a ship's siren, the sound of which was reflected from their surface. The sinking of the first-class liner Titanic in 1912 was the result of negligence, and this was the reason for the very strict safety regulations that still apply to navigation. On the moonless night of April 14-15, the ship continued to move at a speed of 22 knots, despite receiving radio warnings about the presence of floating ice in the area. It hit the iceberg 40 seconds after it was spotted and sank 2 hours 40 minutes later, claiming 1,513 lives.

According to Lord Mersey's report, the ship was lost as a result of a collision with an iceberg, and this happened because the ship was traveling at an unacceptably high speed under the circumstances. That's it. And then - numerous conclusions.

“..Never again will people send their ships into ice fields without heeding warnings, relying only on the strength of several thousand tons of riveted steel sheets. Since that memorable night, transatlantic liners will take ice warnings seriously and try to avoid dangerous places or walk at a moderate pace. No one will believe in “unsinkable” ships anymore.

And icebergs will no longer float unattended across the seas. After the sinking of the Titanic, the American and British governments organized an international ice patrol, and today the ships coast guard They keep an eye out for wandering icebergs that drift towards the sea routes. As an extra precaution for winter sea ​​routes shift to the south.

And there are no longer any liners on which radio watches are kept for less than a day. Every passenger ship is required to have a 24-hour radio watch. No more people would die because some Cyril Evans, ten miles away, finished his watch and went to bed.

Many icebergs settle on shallows and gradually melt, but during periods of solar activity North Atlantic literally filled with these icy floating mountains, often shrouded in dense fog. To prevent ships from colliding with icebergs, the Atlantic has been operating since 1914. special service– International Ice Patrol. It is armed with echo sounders and sonars capable of identifying the underwater outlines of icebergs. Special analyzers that signal a sudden drop in salinity and temperature giants. To make icebergs more visible from a distance, they are fired at with shells filled with bright luminous paints. Any ship located in dangerous waters can receive the necessary information and images of the ocean ice cover using satellites.

Usage

In the 60s in special scientific journals The first works appeared on the use of Antarctic icebergs as a source of fresh water. The articles discussed different sides this task related to technical problems transporting ice mountains across the ocean and processing ice into water. The general public learned about the possibilities of using Antarctic icebergs for water supply much later, in the 70s, when this problem began to be discussed in the pages of the mass media. One of the results of a wide discussion of ideas for transporting icebergs was the emergence of a certain company that undertook to develop for a small principality located on deserted shore, a tethered iceberg delivery project. Hundreds of thousands of dollars were received for the development of the project, and then the company disappeared. This was the first “practical” application of the completely feasible idea of ​​​​transporting icebergs to thirst zones - desert and semi-desert regions of the Earth.

The idea of ​​transporting icebergs continued to develop. In 1974, a seminar on this problem was held in the USA: In 1977, an international symposium on the problem of iceberg transportation was held in the state of Iowa. Saudi Prince Mohammed al-Faisal, head of the Salt Water Desalination Corporation in Saudi Arabia, wrote an article devoted to this problem. An International Iceberg Transportation Company has been created, financed from private sources in Saudi Arabia, in which famous glaciologists are involved. The company, together with the International Glaciological Society, organized a new international symposium on the use of icebergs in 1980, which showed that many technical issues of transportation are being solved at the most modern level, and a number of developments are already protected by patents.

At the beginning of the 20th century, there was a project to transport small icebergs produced by Alaskan glaciers to the shores of California. And in the second half of the 20th century, this project was revived on the basis of Antarctic icebergs, the transportation of which to thirst zones is more rational, since they are located in areas located closer to these zones, and their size is significantly larger than the size of icebergs in the northern hemisphere. In principle, many transportation issues have been resolved, and technical details are now being worked out. However, the planned experimental transportation of the iceberg to the shores of Australia has not yet been carried out. And yet, ice from Greenland and Antarctica is exported and sold in the form of cubes for cocktails with the advertising slogan “the purest ice on Earth.”

Since desalination sea ​​water requires large energy costs and is very expensive, then even if we take into account that transporting icebergs is also not cheap, an iceberg is still much more profitable as a source of fresh water than desalination of sea water.

Interesting fact:

In 1942, the idea of ​​creating an aircraft carrier from a floating iceberg arose in England. Such an aircraft carrier, in principle, should be cheap. Due to the fact that it is a solid block of ice, it is not afraid of torpedoes and bombs. Through the joint efforts of England and Canada, such an ice ship with a displacement of 2 million tons was built. It had the shape of a parallelepiped with a wall thickness of 9 m and rose 15 m above the water. In its upper part there was a runway measuring 600x500 m2. 16 refrigeration units were installed on the ship, which maintained the wall temperature at about -15°C. Thanks to the work of 20 thousand strong motors, the iceberg could move at a speed of 7 knots per hour. All superstructures on it were erected from a mixture of ice and sawdust: this material is 4 times stronger than ice, is malleable and has approximately the same explosion resistance as concrete.

Literature:

1) Arabadzhi V.I. Riddles of simple water. M., Knowledge, 1973, 95 p.

2) Kalesnik S.V. Essays on glaciology. M., 1963

3) Losev K.s. “Antarctic Ice Sheet” M., Nauka, 1982.

4) Losev K.s. “Land of Eternal Winter” L., Hydrometeorological Publishing House, 1986.

5) Kotlyakov V.m. “Snow and ice in the nature of the Earth” M., 1986.

Introduction

Ice cover is an important physical and geographical feature of the polar regions of the World Ocean. Significant spatiotemporal variability polar ice determines the need to study them as an integral part of the general climate system of our planet and as the main natural factor, influencing human activity in terms of studying and mastering natural resources polar regions.

The Southern Ocean is a vast physical and geographical region of the World Ocean with an independent water circulation system, characteristic structure water masses, a system of zonal arrangement of frontal zones, the presence of drifting sea ice and icebergs.

Main structural formations, making up the ice cover of the Southern Ocean, are drifting ice, icebergs, fast ice and polynyas, which are characterized by geographical location and size, as well as spatiotemporal variability of their main parameters and elements.

The purpose of this work was to obtain quantitative estimates education large icebergs and the relationship between air temperature in the Southern Hemisphere and the number of large icebergs and water reserves in them, as well as the contribution to the heat balance of the characteristics of the heat of ice melting.

Icebergs

Since in this work the object under study is an iceberg, we will consider the main definitions of this area.

An iceberg is a large monolithic block fresh ice floating in the sea or aground at the time of observation. It can rise above the water level by more than 70-100 m and reach a length of 100 km or more. About 70-90% of the iceberg's volume is usually under water. As a rule, icebergs form from outlet and cover glaciers or shelf ice.

Icebergs from outlet glaciers are table-shaped with a slightly convex upper surface that is dissected various types with irregularities and cracks, these icebergs are characteristic of the Southern Ocean.

Icebergs from cover glaciers are distinguished by the fact that they top surface It's almost never level. It is slightly inclined, like a pitched roof. Their sizes, compared to other types of icebergs in the Southern Ocean, are the smallest.

Icebergs on ice shelves usually have significant horizontal dimensions(tens and even hundreds of kilometers). Their height is on average 35-50 m. They have a flat horizontal surface, almost strictly vertical and smooth side walls.

Distribution and dimensions

The current northern limit of iceberg distribution in the Southern Hemisphere is stable and close to the position of the Antarctic convergence zone. The northernmost position of the iceberg (50 m high, 4000 m long and 700 m wide), in the current century from documented sources, was noted on December 27, 1982 at 49°30 S and 40°20 W. In addition, over the past 10 years, icebergs longer than 1500 m have become much more common north of 65° S. Total quantity There were 316 such icebergs during this period.

The probability of occurrence of icebergs with a height of 100-150 m is less than 50%, and a length of over 3000 m in the coastal zone is no more than 5% (see Appendix, Figure 1). Giant icebergs are a rare phenomenon. Average length for icebergs located between the coast and 65° S, it is 1090 m; to the north it decreases by almost 2.5 times and amounts to 430 m. Changes in the height of the surface part of icebergs, depending on latitude, are very insignificant. So, in the coastal zone south of 65° S, average height icebergs is 50 m, and to the north - 48 m. The average ratio of the width of an iceberg to their length is almost constant and equal to 0.6. The ratio of the surface part of icebergs to the underwater part varies more significantly and depends on the shape of the icebergs, and on average is 0.6 - 0.7.

The distribution density of icebergs or their number per 1000 km. (see Appendix, Figure 2), corresponds to the basic patterns of atmospheric circulation, surface waters and ice, their distribution, as well as geographical location main areas of the glacial coast of Antarctica that produce icebergs.

The average lifespan of icebergs in Antarctic waters is about 2 years (with a volume of iceberg runoff into the ocean of 2.2 thousand km/year and a total volume of 4.7 thousand km3 in the ocean).

Where can glaciers form?

Glaciers can form in mountains above the snow line. Glaciers can also form on continents and islands in polar latitudes.

What proportion of the hydrosphere is glaciers?

Glaciers account for 1.8%.

What work do glaciers do on the Earth's surface?

Glaciers perform erosive work, leaving scratches, hollows and carrying with them huge masses of debris. When melting, glaciers perform accumulative work, leaving ridges, hills, and filling plains.

Find and show on the map areas covered by glaciers.

Antarctica, Greenland, islands of the Arctic Ocean, Tibet, Himalayas.

Using Figure 146, determine the limit of the maximum distribution of icebergs.

The limit of maximum distribution of icebergs reaches 520 S latitude. In the Northern Hemisphere, off the coast of North America, floating ice reaches 440 N latitude.

Name the continents where permafrost is common.

Permafrost is found on all continents except Australia. It has become widespread in Antarctica, Eurasia, North America.

Questions and tasks

1. How are glaciers formed?

Glaciers originate in polar regions and in the mountains, where the air temperature is low all year round. More snow falls here in winter than melts in summer. As more and more snow accumulates, it gradually becomes denser and turns into ice.

2. How do cover glaciers differ from mountain glaciers? What are the most glaciers on Earth?

Ice sheets that completely hide land areas with mountains and plains located on them are called cover glaciers. Mountain glaciers form only on the tops and slopes of mountains. There are more cover glaciers.

3. Why are glaciers consisting of solid, are they moving?

Ice is a hard but plastic substance. Therefore, glaciers move slowly - “flow”. The lower layers of ice move under the pressure of the upper ones. The movement occurs from the center of the glaciers to their marginal parts.

4. By physical map around the world, give examples of islands and coastal areas that may be flooded when all the glaciers melt.

In North America, the entire Atlantic coast of the United States, including Florida and the Gulf Coast, will be submerged. Most of California will also be under water. IN Latin America will flood the Argentine capital Buenos Aires, as well as coastal Uruguay and Paraguay. Many areas of Europe will also be destroyed. The British Isles will disappear. The Netherlands and most of Denmark will be under water.

5. Show the largest sheet glaciers on a physical map.

The largest sheet glaciers are located on Antarctica, Greenland, Spitsbergen, Severnaya Zemlya, Canadian Arctic Archipelago.

6. What is permafrost?

Permafrost is rocks cemented by frozen water.

7. Why are water pipes not buried beyond the Arctic Circle, but buildings are built on stilts - supports driven deep into the ground?

Permafrost sometimes thaws, rocks “float” and at the same time the foundations of buildings, pipelines, iron and highways. Therefore, burying pipes and conventional foundations in permafrost conditions are not safe.

8. Is there permafrost in the area where you live? How does it affect economic activity?

Permafrost has great influence on human economic activity. It creates significant obstacles to excavation work, construction and operation of various buildings, etc. Heated buildings erected on permafrost settle over time due to the thawing of the soil underneath them, cracks appear in them, and sometimes they collapse. Permafrost also complicates water supply in populated areas and on railways. This required development special methods construction in permafrost conditions rocks. Permafrost contributes to swamping of agricultural lands, as a result of which additional reclamation work is necessary, i.e., removing excess moisture from the fields. From positive factors two can be distinguished: the creation of natural refrigerators for storing perishable foods and the saving of fastening material in mines and mines.