Where icebergs float. Ice mountains in the ocean

Lesson - game for 6th grade
Goals: develop attention, thinking, help to understand more easily educational material, teach to find relationships between various geographical objects and processes, captivate the subject
Equipment: outline cards, envelopes with charades, puzzles, letters “droplets-travelers”
Progress of the game
Lesson - the game consists of 6 competitions.
1 competition "Mute card"
The teacher distributes outline maps to each team, on which 20 objects are indicated by numbers. Participants in the game need to sign as much as possible in 2 minutes more titles marked geographical objects. You are not allowed to use the atlas when completing the assignment. The correct answer is worth 3 points.
^ 2nd competition "Geographical Associations"
The teacher reads assignments and associations to each team in turn. In this case, teams need to guess the word using the proposed logical series and explain the course of their reasoning. The correct answer is worth 2 points.
Quests:

1. 
   Wave, earthquake, speed, danger, disaster. (Tsunami)
2. 
   River, sea, evaporation, clouds, precipitation. (World water cycle)
3. 
   Wind, water, bottle, letter, Gulf Stream. (Currents)
4. 
   Rocks, rapids, water, spectacle, roar. (Waterfall)
5. 
   Ocean, ice, mountain, Titanic, danger. (Iceberg)
6. 
   Chalk, shell, sea, sediment, bottom. ( Rocks organic origin)

3rd competition “The Journey of the Invisible Droplet”
Each team is given a “traveling droplet” letter. After reading it, you need to mark on contour map all described in a nutshell geographical features. A correct task is worth 5 points.

I am a little invisible drop. One day I rained on the surface himself deep lake peace . I got out of this lake by the only one the river flowing from it and got into the largest of the Russian rivers flowing into Arctic Ocean . I evaporated from the surface of the ocean and, together with my sister droplets, formed a cloud. This cloud was carried by the wind, and it rained on the Russian Plain. Rainwater leaked into groundwater. Groundwater hit V big river flowing into the sea-lake . From this sea-lake I again evaporated, fell into a cloud, and the wind carried this cloud far to the shores big river, starting from the confluence of the Biya and Katun rivers.

It would take a long time to talk about all my travels, but after that I still managed to visit the waters the saltiest sea in the world, swim along most long river Africa , fall from a height world's tallest waterfall and take a swim in the most deep river on the planet.
The contour map should indicate: Lake Baikal, Angara River, Yenisei River, Volga River, Ob River, Dead Sea, Nile River, Angel Falls, Amazon River.

^ Competition 4 “Geographical charades”
There are 4 envelopes on the table with charades written in them. Representatives from teams must choose 2 envelopes and correctly guess the geographical charade. The correct answer is worth 1 point.

Here's an easy charade for you:

You need to add “N” to the note.

The note no longer sings

And it flows like a river. (Don)
The first is flying water,

You will always meet me in a Russian bathhouse.

And secondly, there are brands of cars

From the Russian, guys of the fleet.

Yet together - the capital of France,

This is the city that fashionistas dream about. (Steam + “Izh” = Paris)
The first one can be made from snow,

A piece of dirt could also be one.

Well, the second thing is passing the ball,

This is an important task in football.

Whole people take them on hikes,

After all, without him they will not find the way. (Com + Pass = Compass)
With “H” - I walk in the sky

And I foretell a storm for you.

With "L" - I am a city on the river

Not far from Moscow.

My gingerbread and samovar

Everyone knows: both old and young (Cloud - Tula)
^ Competition 5 "STO"
You need to guess the words that are geographical concepts, titles and names that contain the numeral 100.

STO __ - cardinal direction (East)
__ STO __ - the beginning of the river (Source)
STO __ __ __ __ - the main city of the country (Capital)
__ __ __ __ __ __ __ STO __ - city of Russia, port on the Pacific Ocean (Vladivostok)
__ __ __ STO __ __ __ - the name of the navigator who discovered America (Christopher Columbus)

^ Competition 6 “Geographical puzzles”

You need to figure it out as best you can more puzzles in 5 minutes. The correct answer is worth 2 points.

After all competitions are completed, the number of points earned is calculated and the winner is announced.

Iceberg (German: Eisberg, "ice mountain")- a huge ice floe that has broken off from the edges of a glacier and is drifting in the ocean or sea.
The nature of icebergs was first correctly explained by the Russian scientist Mikhail Lomonosov.

How does an iceberg form?

Under the influence of gravity, large ice floes, or icebergs, break off from the edges of the glacier. The wind and current carry them to warmer waters.
The “factories” of icebergs are the fjord glaciers of Greenland and the ice shelves of Antarctica.

Icebergs formed from continental ice Antarctica, can rise above the water to a height of 100 meters. The largest iceberg ever measured had 322 km long And 97 km wide.

Icebergs formed from glaciers Greenland and the Arctic islands, much smaller - the largest of them rise up to 70 m above the water surface.

In just one year, about 26,000 icebergs.

For about a year 370 icebergs They pose a threat to navigation, especially in the Atlantic Ocean, as currents carry them into areas where ships move. Therefore in open ocean They are under constant surveillance special service.

Above the surface of the sea is approximately 1/10th of an iceberg, and most of them are under water.

In addition, floating in warm waters The ice mountain is usually shrouded in dense fog and it is possible to see the iceberg too late. But today, sailors are warned of danger by radars (radars), which can “see through the fog.

In 1912, in thick fog, the large passenger steamer Titanic collided with an iceberg while crossing Atlantic Ocean. The ship on which two thousand two hundred passengers were sailing to America sank.

Besides ordinary ice, formed as a result of freezing sea ​​water, in some areas of the World Ocean you can find ice mountains - icebergs. These are fragments of glaciers sliding into the sea, various shapes and sizes. Sometimes they look like pyramids, often have the shape of a cube, and in Antarctic waters You can find huge ice masses with a completely flat surface. Under the influence of sunlight and sea ​​waves The shape of icebergs changes over time. The older the iceberg, the more bizarre its shape.
Typically, sea ice is quickly destroyed as it moves from high latitudes to temperate latitudes. Icebergs are more durable. They can be found where sea ice never reaches. Scattered by the whims of winds and currents over a large area of ​​the ocean, icebergs have always posed a serious danger to navigation. In the recent past, when ships did not have radars, encountering icebergs could lead to great trouble. At night or during the day, when visibility was poor, “lookout” sailors were posted at the bow of the ship to observe the sea. But in the darkness or fog of the night, the sailors could notice the danger only a few tens or hundreds of meters away. Therefore, it was often necessary to reduce the speed of the vessel, and sometimes stop completely. However, this did not always guarantee the safety of the ship. Even after the invention of the radar, the possibility of colliding with icebergs, as we will see below, did not completely disappear. From time to time we hear about disasters caused by collisions with icebergs.
In 1912, the whole world was shocked by the news of the sinking of the huge passenger ship Titanic. At that time it was the largest steamship in the world, with a displacement of 52,300 tons, a length of 250 m, and its speed reached 25 knots (46 km/h). It could carry 3,500 passengers.
On April 11, 1912, the Titanic set out on its first voyage from the English port of Queenstown (southern Ireland) to New York, with 2,201 people on board (passengers and crew of the ship); There were 109 children among the passengers.
Competing English shipping companies fought to reduce ocean crossing times. Every day and even hour won increased the influx of passengers, accommodation and cargo. Everything was used to increase the ship's speed and provide passenger comfort. But sufficient life-saving equipment was not provided. The ship had only 16 boats, designed for 1180 people.
The Titanic was moving at full speed, regardless of the weather (poor visibility and fog), average speed at 22 knots. He did not slow down near Newfoundland, where in April there are especially many icebergs, which descend far to the south in the spring. Although there were continuous radio messages from other ships sailing in the area about encounters with icebergs, the captain of the Titanic did not take precautions and proceeded at the same speed, not listening to the advice of his assistants. He was ordered to hurry. After all, the Titanic was supposed to snatch the “blue ribbon” from the best ships of the competing company, Mauritania and Lusitania.
At 11:40 p.m. The “lookout” reported to the bridge: “There’s an iceberg ahead.” The command immediately followed to change course and stop the car, but it was too late: the Titanic full speed ran into an icy mountain. Water poured into a huge hole in the side of the ship and flooded all the compartments of the bow of the ship up to the midship frame. There was no way to pump out the water. The command followed to leave the ship and board the boats. A. Meanwhile, the bow of the Titanic quickly sank into the water, and after 2 hours 40 minutes. After the collision, the ship sank.
The encounter with a formidable iceberg was too unexpected, the speed of the ship was too high, and the means of rescue were too insufficient. Only 712 people were saved. True, the boats were designed for larger number passengers, but the desperate panic that arose on the ship and the short period during which the Titanic stayed afloat after the disaster did their job.
Years have passed. In the area where the Titanic sank in 1913, based on international agreement, a regular iceberg warning service was organized - the International Ice Patrol. Ice Patrol vessels cruised in the area where icebergs were concentrated in the area of ​​the most intense ship traffic. The patrol's area of ​​activity is the waters adjacent to Newfoundland from the northeast, east and southeast. The patrol's job is to keep track of icebergs, monitor their progress and warn approaching ships about the risk of collision.
In the 30s of our century, a radar was invented, which makes it possible, even in poor visibility, to receive on the device’s screens an image of an iceberg or an oncoming ship sailing at a considerable distance from the ship. But this still could not completely prevent collisions with icebergs, leading to disasters. As reported in our press, on January 30, 1959, 36 miles southeast of the southern tip of Greenland (Cape Farvel), the Danish motor ship Hans Hedtoft crashed and sank after colliding with an iceberg. The ship was sailing outside the Ice Patrol's coverage area.
The Hans Hedtoft, with a displacement of about 3,000 tons, was built in 1958. Like the Titanic, it made its maiden voyage. The ship was equipped with the latest radar equipment. The motor ship had a double bottom, seven transverse waterproof bulkheads, special ice fastenings and a variety of life-saving equipment (a spacious motor boat, boats and inflatable rafts). Despite this, the ship sank quite quickly and of the 95 people on board the ship (40 sailors, 55 passengers, including 19 women and 6 children), none managed to escape. From the first telegram, broadcast immediately after the collision at 17:58, 3 hours and 50 minutes passed to the last telegrams. Two minutes before the laconic last telegram - “We are going to the bottom”, the radio operator of the ship radioed: “The ship is slowly sinking. We request all vessels to immediately come to the rescue. Our coordinates are 59 degrees 05 northern latitude, 43 degrees west longitude."
It remains a mystery why the crew of the ship did not use the lifeboats. Some light is shed by the message of the German fishing vessel Johannes Kreyes, which was closest to the site of the ship accident. The captain of the Craes radioed the emergency vessel fifteen times, but none of the radiograms from the ship reported the captain's intention to lower the boats and abandon the ship. Probably the captain of the ship, Raus Rassmussen, who had been sailing in polar waters for thirty years, was sure that his ship would not sink and tried to save the ship. But in last minute something unexpected happened that accelerated the death of the ship. Most likely it turned upside down, burying the entire crew under it.
The search for the castaways, carried out for several days by ships and aircraft, was unsuccessful. But sometimes radar screens do not produce a distinct image of an iceberg that is clearly visible to the naked eye. This happens when the iceberg protrudes slightly above the water or has an inclined side facing the ship. The Hans Hedtoft, in all likelihood, collided with a small iceberg, slightly protruding above the surface of the sea, the image of which on the radar screen could easily be obscured by the display of the waves.
But a collision with an iceberg does not always lead to the death of a ship. In January 1956, the Soviet expedition ship Lena collided with an iceberg in the Davis Sea in the fog on its way to the village of Mirny (Antarctica). The ship hit the iceberg with the left rock (the bow of the port side), tilted sharply and lost speed. However, there was no damage to the hull.
In 1958-1959 In Newfoundland waters, three of our ships were damaged from encountering floating ice and icebergs in poor visibility conditions: Chernyshevsky, Radishchev and Noginsk.
Where are icebergs most often found? Icebergs can be found in Northern Arctic Ocean and its seas, in the northwestern part of the Atlantic and in southern parts Pacific, Atlantic and Indian oceans. Icebergs are especially numerous in the waters surrounding Greenland and the Antarctic continent.
Icebergs are extremely rare in the North Pacific Ocean. The main “supplier” of icebergs in this area is the Malaspina glacier in the Gulf of Alaska, which descends directly into the ocean at a latitude of 60°.
Icebergs of the Arctic Ocean are supplied by the glaciers of the islands of Spitsbergen, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya and Greenland.
The most powerful glaciers are in Greenland. That is why the largest icebergs are found in the northern hemisphere near its shores: in the Baffin Sea, Davis Strait and the Greenland Sea. Icebergs born from glaciers on other islands of the Arctic Ocean are significantly smaller in size than Greenland ones.
Occasionally, ice mountains can be found far beyond the boundaries indicated on maps. So, one day, a fragment of an ice mountain was encountered at 36° 10" N and 39° W, that is, at 650 nautical miles southeast of the Great Bank of Newfoundland and 360 miles from the usual limit of iceberg distribution.
There was a case when an iceberg was discovered 500 miles west of Ireland, that is, at a very great distance from the distribution limit of icebergs. But such cases are extremely rare.
The same was noted for the southern hemisphere. The ship "Dohra" encountered an iceberg in 1894 500 miles from the border of their distribution. The Ice Mountain was apparently in last stage destruction, since only a giant iceberg could penetrate such low latitudes (26° S and 26° W) and not melt along the way. All types of icebergs are found in Antarctica: table-shaped, pyramidal, dome-shaped (hill icebergs), broken and inclined. But the most characteristic of Antarctica are table-shaped ice mountains, which are not found at all in the Arctic.
Icebergs are varied in size. In the ocean you can also see small pieces of ice - iceberg fragments and huge ice islands.
The ice that icebergs are made of is completely fresh. Usually only 1/5 or 1/6 of the entire iceberg rises above the water, the rest is hidden under water. Sometimes an underwater projection forms near an iceberg - a ram.
On average, the height of ice mountains above sea level in the northern hemisphere is 70 m, and in the southern hemisphere it is slightly less - 40-50 m. But occasionally there are ice mountains with a height of 150-200 m and even 800 m.
The horizontal dimensions of icebergs, especially Antarctic ones, can also be quite significant. In December 1854, a huge ice mountain 90 m high was encountered in the Atlantic Ocean. It stretched 75 km in length and 11 km in width. Until April 1855, this mountain was seen by the crews of 21 ships.
One of the very large icebergs was seen in the Atlantic Ocean east of the Falkland Islands; it was 150 km long. But perhaps the largest was the iceberg encountered by the sailors of the American icebreaker Glacier in November 1956, west of Scott Island. It was 333 km long and 96 km wide.
An expedition on the diesel-electric ship "Ob" in February 1958 in the area of ​​the Ninnis glacier encountered an iceberg 80 km long. A year later, apparently, the same iceberg was observed by the whalers of the Slava.
The largest icebergs are found close to their places of origin. Most of them are destroyed by sea waves and temperature. They crumble into many small ice mountains, making swimming very difficult. However, some large icebergs that do not have deep cracks remain unbroken and are carried by winds and currents to low latitudes. Icebergs in the southern hemisphere can float across the ocean from the moment they break away from the glacier until they are completely destroyed for about 10 years. Lifespan of icebergs northern hemisphere significantly less and does not exceed 5 years. The age of Greenland icebergs is even less (no more than 2-3 years). The reasons for the shorter lifespan of northern icebergs are that they are quickly carried by the Labrador Current to low latitudes, where they melt.
Antarctic icebergs, as a rule, do not break through the cross-current ring that encircles the entire globe along the 40-45 parallel.
Icebergs never reached the equator, much less traveled from one hemisphere to the other. Therefore, the note of the Turkish newspaper, reproduced by Vechernaya Moskva on February 24, 1958, sounds absolutely fantastic. In the note “Find in an Iceberg” in the “briefly about miscellaneous” section, the newspaper wrote: “Sailors of the American fleet blew up a huge block of ice off the coast of Antarctica with dynamite. Imagine their amazement when a well-preserved corpse of a man appeared from the fissure... in a tuxedo. It was soon established that this was one of the passengers of the transatlantic steamship Titanic, which sank after colliding with an iceberg in 1912.”
Apparently, some mistake was made here, or the entire message from beginning to end is fictitious.
Of interest is the project of towing icebergs from polar regions to tropical areas where there is a shortage of water. This project was undertaken by the American scientist John Isaacs from the Scripps Oceanographic Institution in La Jola (California, USA). He proposed a plan to tow large Antarctic icebergs to the Southern California region, for which the water supply problem is vital. Isaacs believes that if you use favorable sea currents, then to implement his plan you will need only 6 powerful ocean tugs with a total capacity of 80,000 hp. With. The towing route can be chosen so that sea currents will help the iceberg move. Indeed, sometimes the Peruvian Current carries icebergs very far into low latitudes. You can select a sufficiently large and well-preserved iceberg in Antarctic waters and, using the Peruvian Current, tow it to the equator. Then, with the southern trade wind current, move somewhat away from the mainland and somewhere west of the Galapagos Islands enter the region of the equatorial countercurrent, directed from west to east. This current will help tugboats pull the iceberg towards the Isthmus of Panama. Here the equatorial current is divided into two branches - northern and southern. The northern branch of the current will carry the iceberg to its destination - the shores of California.
In warm tropical waters, the iceberg will melt rapidly, so its preservation will require special protection made of heat-insulating material about three meters thick.
Isaacs calculated that to supply fresh water Southern California for a year (which is currently spending $100,000,000) will require a very large iceberg - 20 miles (37 km long, 1/2 mile wide) and with a draft of 300 m. This form of iceberg is most convenient: the narrow part of it giant ice "brick" will have the least impact drag when towing.
The success of the operation depends on the speed of towing (according to Isaacs it will take 6 months) and the quality of protection.
According to Isaacs's assumption, the loss of the iceberg during towing in the subtropics will be to some extent compensated by the condensation of moisture from the atmosphere on the iceberg, especially while it is parked near California, which can provide an additional 25% of water.
Fresh water formed during the melting of the iceberg during its stay, being lighter, will accumulate on the surface of the ocean, therefore, a circular protection made of waterproof material should be built around the iceberg, somewhat elevated above the water, but not very deep below the surface. From this reservoir water can be continuously pumped inland.
The operation of towing an iceberg is associated with great difficulties, and Isaac's project was met with great skepticism in US scientific circles. The director of the Woodshall Oceanographic Institution, Edward Henson Smith, considers it “speculative and at the same time fantastic.”
However, attempts have been made to use icebergs for human needs of a more realistic nature. When fishing fleets operate, icebergs can serve as excellent landmarks. You can stand behind icebergs during periods of disturbance and carry out the necessary cargo operations. Participants of the Soviet Antarctic expedition in 1957-1958. Table-shaped icebergs were widely used for landing airplanes and helicopters with field scientific parties.
But still, the harm caused to humans by icebergs cannot be compared with the benefits that can be derived from them. That is why studying the life of icebergs and predicting their paths is one of the most important problems physical oceanography.

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11. Ice in the ocean.

© Vladimir Kalanov,
"Knowledge is power."

Ice is the solid phase of water, one of its aggregate states. Pure fresh water freezes at a temperature almost equal to zero (below zero by only 0.01-0.02 ° C). At the same time, water that has been purified in the laboratory to the maximum possible extent and is in a calm state can be cooled without forming ice to a temperature of minus 33°C. But the smallest piece of ice or other tiny object placed in such supercooled water will instantly cause rapid ice formation.

Normal ocean water, with a salinity of 35‰, freezes at minus 1.91°C. At a salinity of 25 ‰ (White Sea) water freezes at a temperature of minus 1.42°C, at a salinity of 20 ‰ (Black Sea) - at minus 1.07°C, and in the Sea of ​​Azov (salinity 10 ‰) surface water freezes at a temperature minus 0.53°C.

Freezing fresh water does not change its composition. The situation is different when sea water freezes. Freezing begins with the formation of thin, elongated ice crystals, which contain absolutely no salt. Gradually, when the lumps of these crystals begin to freeze, salt gets into the ice.

The salinity of sea ice, i.e. the salinity of the water formed during its melting averages about 10% salinity ocean water. Over time, this figure decreases, and multi-year ice can be almost fresh.

The volume of ice is 9 percent greater than the volume of water from which it was formed, because... V crystal lattice Ice packing of water molecules is ordered and becomes less dense. Therefore, the density of sea ice is less than the density of sea water and ranges from 0.85-0.94 g/cm 3 . That's why floating ice rise above the surface of the water by 1/7 - 1/10 of their thickness.

Strength sea ​​ice noticeably lower than freshwater, but it increases with decreasing temperature and salinity of ice. Have the greatest strength multi-year ice.

Ice 60 cm thick, which forms on freshwater bodies in the depths of winter, can withstand a load of up to 15-18 tons, if, of course, this load is not applied concentratedly, but in the form of, say, a cargo platform on a caterpillar track, the supporting surface of which is approximately 2 .5 m2.

At this point we will make a small digression, but not at all lyrical. Lake Ladoga, as is known, has only a weak connection with the oceans and ocean ice. But we want to remind you that in 1941-1942 the ice “Road of Life” was laid along this lake, which saved the lives of many tens of thousands of people. Our young readers should definitely become familiar with the heroic and dramatic history of the construction and operation of this legendary road of life.

In the oceans, ice forms in high and temperate latitudes. In the polar regions, ice remains for several years. These perennial, so-called pack ice reaches its greatest thickness in central regions Arctic Ocean - up to 5 meters. Sea ice begins to melt when its temperature exceeds minus 23°C. In the Arctic in summer, the thickness of ice due to the melting of its upper layers can decrease by 0.5-1.0 meters, but over the winter up to 3 meters of ice can freeze below. This multi-year ice is gradually carried by currents to temperate latitudes, where it melts relatively quickly. It is believed that the lifespan of Arctic ice that forms off the coast of Russia ranges from 2 to 9 years, and Antarctic ice lasts even longer. Largest sizes Ice cover in the oceans reaches at the end of winter: in the Arctic it covers an area of ​​about 11 million km 2 by April, and about 20 million km 2 in the Antarctic by September. If we talk about permanent ice cover , then it makes up 3-4 percent of the total area of ​​the World Ocean.

Ice cover may consist not only of fast ice, i.e. motionless ice frozen to the shore, but also moving drifting ice With a strong wind coinciding in direction with the sea current, drifting ice can travel a distance of up to 100 km per day.

Falling snow often creates large drifts on the ice. The snow gradually freezes, increasing the thickness of the ice cover. Sometimes hurricane-force winds break the ice, creating high hummocks. On such ice, if we talk about the Arctic, only polar bear, and even then with great difficulty.

But the ocean also contains ice that formed on land. These are the so-called icebergs - huge blocks fresh ice (German Eisberg - ice mountain). Icebergs are delivered to the ocean by continental glaciers at polar latitudes. The largest ice sheet on Earth is located in Antarctica. Its area is 13.98 million km 2, i.e. 1.5 times the area of ​​Australia. At the same time, the area of ​​the continent of Antarctica itself is estimated at 12.09 million km 2. the rest is accounted for by the ice that covers almost the entire shelf of Antarctica. Average thickness Antarctic ice is 2.2 km, and the largest is 4.7 km. The volume of ice is estimated at 26 million cubic kilometers. The enormous weight of ice pressed this continent into earth's crust. As a result, much of Antarctica's surface lies below sea level. The Antarctic glacier annually receives 2000-2200 km 3 of ice from snow and loses about the same amount to icebergs. Of course, this balance cannot be accurately calculated. Therefore, the scientific world does not yet have a clear answer to the question of whether the Antarctic glacier is increasing or decreasing.

Icebergs in the form of huge blocks, similar to mountains, slowly slide from the mainland into the sea, and then crash into the water with a roar. In Antarctica, the largest volume of ice in the form of icebergs is provided by two giant ice shelves advancing into the Ross and Weddell Seas. For example, the Ross Ice Shelf has an area exceeding 500 thousand km 2, and the ice thickness here reaches 700 meters. In the Ross Sea, this glacier approaches in the form of a huge ice barrier almost 900 km long and up to 50 meters high.

There are about 100 thousand icebergs constantly floating around Antarctica. Comprehensive monitoring, including monitoring of icebergs, is carried out by 35 people working here scientific stations from different countries. Russia has 8 scientific stations here, the USA - 3, Great Britain - 2. Ukraine, Poland, Argentina and other countries also have Antarctic scientific stations.

The international legal regime of Antarctica and other territories located south of 60° S is regulated by the Antarctic Treaty of December 1, 1959.

In the Northern Hemisphere, the main supplier of icebergs to the ocean is Greenland. It is believed that up to 15 thousand huge pieces of ice break off from the glaciers of this island every year. From here they sail into one of the busiest areas of the Atlantic Ocean.

Icebergs also break off from the glaciers of the islands of the Arctic Ocean - Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, Spitsbergen and the Canadian Arctic Archipelago.

In general, glaciers occupy 16.1 million km 2 of land, of which 14.4 million km 2 are covered by ice sheets (85.3% in Antarctica, 12.1% in Greenland). In terms of area and volume of water, glaciers occupy second place on Earth after the World Ocean, and in terms of fresh water content they surpass all rivers, lakes and groundwater, taken together.

Icebergs are table-shaped and pyramidal in shape. The table-shaped shape is characteristic of Antarctic icebergs, which are formed when they are separated from a huge mass of ice of a homogeneous structure. When glaciers move relatively quickly, the shape of the broken pieces often resembles a pyramid. As the underwater and surface parts melt unevenly, icebergs take on various, most bizarre shapes, and with loss of stability they can capsize.

Icebergs can reach enormous sizes. Especially large icebergs form from the ice shelves of Antarctica. In 1987, with the help of Earth satellites, an iceberg 153 km long and 36 km wide was discovered in the Ross Sea area.

An iceberg called B-15 broke off from the same glacier in 2000. This giant had an area of ​​more than 11,000 km 2. If an ice floe of this area were on Lake Ladoga, then it would cover 63% of the surface of this large (17.7 thousand km 2) lake.

The mass of such giants can amount to hundreds of millions and even billions of tons. But this is clean fresh water, the shortage of which has long been felt by many countries.

The heat capacity of ice melting is very high. It takes 80 calories to melt 1 gram of ice, not counting the heat it takes to warm the ice to zero degrees. It is no coincidence that projects have long arisen to tow icebergs to the shores of such coastal states as Japan, Saudi Arabia, Kuwait, UAE. Calculations show that an iceberg of “medium” size: 1 km long, 600 m wide and a total height of 300 m during the towing journey, for example, from Antarctica to Saudi Arabia, will lose no more than 20% of its volume. The initial weight of such an iceberg would be about 180 million tons (in water it is much less). If towing an iceberg of this size remains a technically difficult task, then the delivery of relatively small ice fragments with a volume of 200-300 thousand cubic meters is quite doable and is already carried out from time to time by the countries mentioned above.

Having broken off from glaciers, icebergs, picked up by currents and driven by winds, sometimes float far beyond the polar regions. Antarctic icebergs reach the southern coast of Australia, South America and even Africa. Icebergs from Greenland penetrate into the North Atlantic up to forty degrees north latitude, i.e. latitudes of New York, and sometimes further south, reaching the Azores and even Bermuda.

The cruising range of icebergs and the time of their existence in the ocean depend not only on the direction and speed of sea currents, but also on the physical properties of the icebergs themselves. Very large and deeply frozen (down to minus 60 degrees) Antarctic icebergs exist for several years, and in some cases even decades.

Greenland icebergs melt much faster, in just 2-3 years, because... they are not so large in size and their freezing temperature is no more than minus 30 degrees.

It is unnecessary to explain what danger floating ice mountains pose for shipping. More than once collisions with icebergs have led to disasters at sea. But none of these disasters can compare with the tragedy that took place at the beginning of the 20th century in the North Atlantic.

Nowadays, the danger of collision with icebergs has decreased significantly compared to the times of the Titanic. Quite reliable radar and other equipment is installed on sea vessels, in ports, and on artificial earth satellites to monitor, alert and warn about the danger of encountering icebergs. In the North Atlantic, where there are busy sea routes, a special ice patrol . It warns ship captains about the locations of large icebergs. The International Ice Patrol includes 16 countries. His ships detect icebergs, warn about the location of icebergs and the direction of their movement. The functions of the ice patrol also include the fight against icebergs, which is carried out with the help of explosions, the use of incendiary bombs, and dark colors. ice blocks, for example, by applying a layer of soot to the surface of an iceberg to speed up the melting process, etc.

However, the measures taken cannot be exhaustive. Icebergs appear in the ocean according to the laws of nature. No one can completely guarantee sea vessels against ice hazards. The ocean is large and often fraught with dangers, for which it is always necessary to prepare in advance.

© Vladimir Kalanov,
"Knowledge is power"

Our Earth is called the blue planet. And not by chance. After all, 70% earth's surface is made up of water. Water exists not only in liquid, but also in solid state (with negative temperatures). Solid water is ice, glaciers that make up the Earth's ice shell. Glaciers are perennial masses of ice formed by the accumulation and transformation of snow, which move under the influence of gravity and take the form of streams, convex sheets or floating slabs (ice shelves). Polar glaciers almost always reach the oceans and seas and actively interact with them, which is why they are called “marine”. Glaciers can invade cold, shallow seas, moving onto the continental shelf. The ice sinks into the water, which leads to the formation of ice shelves - floating slabs consisting of firn (compressed porous snow) and ice. Icebergs periodically break off from them. At contact with the sea, the movement of ice streams accelerates, their ends float up, forming floating tongues, which also become the source of a huge number of icebergs.

“Ice” in German means ice, “berg” means mountain. Icebergs are large fragments of glaciers that descend from land to the sea. They are carried far away by sea currents. And it’s amazing - sometimes the ice mountains seem to float against the current. This happens because only an eighth or ninth of the entire iceberg rises above the surface of the water, the rest is immersed deep in the water, where the current is sometimes opposite to that on the surface.

Translated into Russian, the word “iceberg” means “ice mountain”. These are truly floating mountains of ice, born from glaciers sliding into the sea. The end of the glacier hangs over the sea for some time. It is undermined by tides, sea currents, and winds. Finally it breaks off and falls into the water with a crash. Every year, ice streams form tens of cubic kilometers of ice per year. All Greenland glaciers annually throw out more than 300 km3 of ice into the ocean, ice streams and ice shelves in Antarctica - at least 2 thousand km3.

Greenland icebergs- often real ice mountains of a dome-shaped or pyramidal shape. They can rise above the water by 70 - 100 m, which is no more than 20-30% of their volume, the remaining 70-80% is hidden under water. With the East Greenland and Labrador Currents, masses of icebergs are carried up to 40-500 north latitude, in some cases even further south.

Encountering icebergs in the ocean is dangerous. After all, its underwater part is not visible. In 1912, the large passenger steamer Titanic sailed from America to Europe, collided with an iceberg in the fog and sank. But it happened that in Antarctic waters icebergs served the Yuri Dolgoruky whaling flotilla well. Severe storms prevented sailors from reloading finished products onto the refrigerator and take fuel from the tanker. And then the sailors saw two icebergs nearby. There were high waves all around, and between them there was only a slight swell. The sailors risked standing between the icebergs and, under their protection, performing the necessary overload. It seems that this is the only case when icebergs helped sailors. But icebergs are not only a majestic natural phenomenon. They can serve as a source of fresh water, which is increasingly scarce for people. Projects are already being developed to “catch” and tow icebergs to waterless areas such as Saudi Arabia and South-West Africa.

Any creation of nature is unique and inimitable. Ice Mountains in the ocean - an unforgettably beautiful and majestic picture. They have the most bizarre shapes and are amazingly colored. They look like giant crystals precious stones: bright green, dark blue, turquoise. This is how they refract sun rays in perfectly clean polar ice floes saturated with air bubbles. Because of these bubbles, which are much lighter than water, icebergs are immersed in water only five-sixths of their volume.

The true size of icebergs far exceeds imagination. In the Arctic, these mountains of ice rise above sea level by an average of 70 m, sometimes reaching a height of 190 m, and the length of some of them reaches several kilometers. A drifting station operated on such ice islands. North Pole– 6" and the first American Arctic stations in the Arctic Ocean. The flat-topped masses of Antarctic icebergs have average height the surface part is 100 m, and some of them rise above the water by 500 m and have a length of 100 km or more.

Sea currents and winds pick up icebergs and carry them from the polar seas to the ocean. IN Southern Hemisphere Large Antarctic icebergs penetrate especially far into the Atlantic Ocean, here they reach 260 south latitude, i.e. to the latitude of Rio de Janeiro, in the Pacific and Indian Oceans icebergs do not float north of 50-400 south latitude.

In the Northern Hemisphere, especially many Arctic icebergs are carried by the East Greenland and Labrador currents into the Atlantic Ocean, where they reach the latitude of England. And here, on the routes of busy transatlantic shipping, they pose a serious threat to ships. But modern ships are equipped with sophisticated instruments that warn at a great distance of the approach of any obstacle, including icebergs.

With the help of icebergs, as we have already said, it would be possible to solve the problems of supplying the arid regions of the Earth with fresh water. The famous American oceanographer and engineer John Isaacs came up with a tempting idea - to tow a large iceberg to the shores of water-stricken California, and use the water generated when the iceberg melts to irrigate dry lands. It can be assumed that the colossal mass of ice, which will melt very slowly even in the hot Californian climate, can cause increased condensation of atmospheric moisture and additional precipitation. This will lead to an increase in water reserves in the reservoir and a slight decrease in the dry climate on the coastline adjacent to the iceberg. This can be used in other arid areas as well globe, and above all in Australia.

The largest icebergs are born from the giant glaciers of Antarctica. From time to time, deep cracks form in the glacier, and it splits into separate blocks. The birth of an iceberg is a spectacular sight. A huge mass of ice falls into the water with a roar reminiscent of a monstrous explosion. Once in the water, the iceberg sets off to swim. Currents sooner or later carry it to warmer latitudes, where it is washed by warm waters and it slowly melts under the rays of the sun. But especially large icebergs manage to move far to the south if they are Arctic icebergs, or far to the north if they are Antarctic. In just one year, about 26 thousand icebergs break off from the Arctic ice cover. The largest iceberg was recorded in the Ross Sea in October 1987. It broke off from the ice shell of Antarctica. The area of ​​the giant is 153 by 36 km.

During the year, approximately 370 icebergs pose a threat to navigation. Therefore, in the open ocean, they are constantly monitored by a special service. Icebergs can reach a height of 100m above the sea surface, but most of them are under water. An ice mountain floating in warm waters is usually shrouded in dense fog - this is water vapor from warmer air condensing over its cold surface. In 1912, the large passenger steamer Titanic, which was crossing the Atlantic Ocean, collided with an iceberg in thick fog. The ship on which two thousand two hundred passengers were sailing to America sank. One and a half thousand people died. Many years later, in 1959, the Danish ship Hedtof suffered the same fate. It also sank in the North Atlantic. An iceberg is a kind of fresh water reservoir.

Even a relatively small ice mountain, 150 m thick, 2 km long and half a kilometer wide, contains almost 150 million tons of fresh water, and of very high quality. This amount of water would be enough for a whole month for such a gigantic city as Moscow, with a population of millions. In the USA, projects are being developed to transport icebergs to the multimillion-dollar city of Los Angeles, to the port cities of South America, Africa, and Australia. Of course, there are many difficulties. We need very powerful tugboats, we need to learn how to securely secure the iceberg with cables, and when delivering it to the port, make sure that it does not melt too quickly. It is important to lay out the most advantageous path for the iceberg in the ocean in order to take advantage of favorable currents and winds.

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