Ice- mineral with chemical formula H 2 O, represents water in a crystalline state.
Chemical composition of ice: H - 11.2%, O - 88.8%. Sometimes it contains gaseous and solid mechanical impurities.
In nature, ice is represented mainly by one of several crystalline modifications, stable in the temperature range from 0 to 80°C, with a melting point of 0°C. There are 10 known crystalline modifications of ice and amorphous ice. The most studied is ice of the 1st modification - the only modification found in nature. Ice is found in nature in the form of ice itself (continental, floating, underground, etc.), as well as in the form of snow, frost, etc.
See also:
STRUCTURE
The crystal structure of ice is similar to the structure: each H 2 0 molecule is surrounded by the four molecules closest to it, located at equal distances from it, equal to 2.76Α and located at the vertices of a regular tetrahedron. Due to the low coordination number, the ice structure is openwork, which affects its density (0.917). Ice has a hexagonal spatial lattice and is formed by freezing water at 0°C and atmospheric pressure. The lattice of all crystalline modifications of ice has a tetrahedral structure. Parameters of an ice unit cell (at t 0°C): a=0.45446 nm, c=0.73670 nm (c is double the distance between adjacent main planes). When the temperature drops, they change very little. H 2 0 molecules in the ice lattice are connected to each other by hydrogen bonds. The mobility of hydrogen atoms in the ice lattice is much higher than the mobility of oxygen atoms, due to which the molecules change their neighbors. In the presence of significant vibrational and rotational movements of molecules in the ice lattice, translational jumps of molecules from the site of their spatial connection occur, disrupting further order and forming dislocations. This explains the manifestation of specific rheological properties in ice, which characterize the relationship between irreversible deformations (flow) of ice and the stresses that caused them (plasticity, viscosity, yield strength, creep, etc.). Due to these circumstances, glaciers flow similarly to highly viscous liquids, and thus natural ice actively participates in the water cycle on Earth. Ice crystals are relatively large in size (transverse size from fractions of a millimeter to several tens of centimeters). They are characterized by anisotropy of the viscosity coefficient, the value of which can vary by several orders of magnitude. Crystals are capable of reorientation under the influence of loads, which affects their metamorphization and the flow rate of glaciers.
PROPERTIES
Ice is colorless. In large clusters it takes on a bluish tint. Glass shine. Transparent. Has no cleavage. Hardness 1.5. Fragile. Optically positive, refractive index very low (n = 1.310, nm = 1.309). There are 14 known modifications of ice in nature. True, everything except the familiar ice, which crystallizes in the hexagonal system and is designated as ice I, is formed under exotic conditions - at very low temperatures (about -110150 0C) and high pressures, when the angles of hydrogen bonds in the water molecule change and systems are formed, different from hexagonal. Such conditions resemble those in space and do not occur on Earth. For example, at temperatures below –110 °C, water vapor precipitates on a metal plate in the form of octahedra and cubes several nanometers in size - this is the so-called cubic ice. If the temperature is slightly above –110 °C and the vapor concentration is very low, a layer of extremely dense amorphous ice forms on the plate.
MORPHOLOGY
Ice is a very common mineral in nature. There are several types of ice in the earth's crust: river, lake, sea, ground, firn and glacier. More often it forms aggregate clusters of fine-crystalline grains. Crystalline ice formations are also known that arise by sublimation, that is, directly from the vapor state. In these cases, the ice appears as skeletal crystals (snowflakes) and aggregates of skeletal and dendritic growth (cave ice, hoarfrost, hoarfrost, and patterns on glass). Large well-cut crystals are found, but very rarely. N. N. Stulov described ice crystals in the northeastern part of Russia, found at a depth of 55-60 m from the surface, having an isometric and columnar appearance, and the length of the largest crystal was 60 cm, and the diameter of its base was 15 cm. From simple forms on ice crystals, only the faces of the hexagonal prism (1120), hexagonal bipyramid (1121) and pinacoid (0001) were identified.
Ice stalactites, colloquially called “icicles,” are familiar to everyone. With temperature differences of about 0° in the autumn-winter seasons, they grow everywhere on the surface of the Earth with the slow freezing (crystallization) of flowing and dripping water. They are also common in ice caves.
Ice banks are strips of ice cover made of ice that crystallizes at the water-air boundary along the edges of reservoirs and bordering the edges of puddles, the banks of rivers, lakes, ponds, reservoirs, etc. with the rest of the water space not freezing. When they completely grow together, a continuous ice cover is formed on the surface of the reservoir.
Ice also forms parallel columnar aggregates in the form of fibrous veins in porous soils, and ice antholites on their surface.
ORIGIN
Ice forms mainly in water basins when the air temperature drops. At the same time, an ice porridge composed of ice needles appears on the surface of the water. From below, long ice crystals grow on it, whose sixth-order symmetry axes are located perpendicular to the surface of the crust. The relationships between ice crystals under different formation conditions are shown in Fig. Ice is common wherever there is moisture and where the temperature drops below 0° C. In some areas, ground ice thaws only to a shallow depth, below which permafrost begins. These are the so-called permafrost areas; In areas of permafrost distribution in the upper layers of the earth's crust, so-called underground ice is found, among which modern and fossil underground ice are distinguished. At least 10% of the Earth's total land area is covered by glaciers; the monolithic ice rock that composes them is called glacial ice. Glacial ice is formed primarily from the accumulation of snow as a result of its compaction and transformation. The ice sheet covers about 75% of Greenland and almost all of Antarctica; the largest thickness of glaciers (4330 m) is located near the Byrd station (Antarctica). In central Greenland the ice thickness reaches 3200 m.
Ice deposits are well known. In areas with cold, long winters and short summers, as well as in high mountainous regions, ice caves with stalactites and stalagmites are formed, among which the most interesting are Kungurskaya in the Perm region of the Urals, as well as the Dobshine cave in Slovakia.
When sea water freezes, sea ice is formed. The characteristic properties of sea ice are salinity and porosity, which determine the range of its density from 0.85 to 0.94 g/cm 3 . Because of such low density, ice floes rise above the surface of the water by 1/7-1/10 of their thickness. Sea ice begins to melt at temperatures above -2.3°C; it is more elastic and more difficult to break into pieces than freshwater ice.
APPLICATION
In the late 1980s, the Argonne laboratory developed a technology for making ice slurry that can flow freely through pipes of various diameters without collecting in ice build-ups, sticking together, or clogging cooling systems. The salty water suspension consisted of many very small round-shaped ice crystals. Thanks to this, the mobility of water is maintained and, at the same time, from the point of view of thermal engineering, it represents ice, which is 5-7 times more effective than simple cold water in cooling systems of buildings. In addition, such mixtures are promising for medicine. Experiments on animals have shown that microcrystals of the ice mixture pass perfectly into fairly small blood vessels and do not damage cells. “Icy Blood” extends the time during which the victim can be saved. Let's say, in case of cardiac arrest, this time lengthens, according to conservative estimates, from 10-15 to 30-45 minutes.
The use of ice as a structural material is widespread in the polar regions for the construction of dwellings - igloos. Ice is part of the Pikerit material proposed by D. Pike, from which it was proposed to make the world's largest aircraft carrier.
Ice - H 2 O
CLASSIFICATION
| Strunz (8th edition) | 4/A.01-10 |
| Nickel-Strunz (10th edition) | 4.AA.05 |
| Dana (8th edition) | 4.1.2.1 |
| Hey's CIM Ref. | 7.1.1 |
The objects of study of glaciology are snow cover, glaciers, ice covering rivers, lakes and seas, underground ice, etc. Glaciology studies the regime and dynamics of their development, interaction with the environment, and their role in the evolution of the Earth.
Snow and ice form the Earth's glaciosphere, which significantly influences the latitudinal zonation of natural processes and global circulation. The glaciosphere, which is very variable and in the past, at some stages of earth's history, disappeared completely. Its existence depends on the geographical latitude and altitude above sea level. The lower limit of the frost level of the atmosphere (in which water exists in the solid phase) in the Arctic is close to sea level, and in the south of Russia, in the Caucasus, at an altitude of 2400–3800 m. Vast ice masses at the poles cause large climatic contrasts and activate circulation atmosphere.
In the northern and high-mountainous regions, as a result of the accumulation and transformation of solids with their positive long-term balance, glaciers are formed. Under the influence of gravity, the ice mass undergoes visco-plastic deformation and takes the form of a flow. The areas of recharge (accumulation) and discharge (ablation) are separated by the glacier's recharge boundary. Perennial snow and ice exist within a fairly narrow range of conditions determined by climate and topography. Despite the diversity of climate, in every mountainous country in the temperate zone, the glaciated region occupies a strictly defined climatic zone, where the average annual temperature is 2–5°C.
There are two main groups of glaciers: mountain glaciers, the shape and movement of which are determined mainly by the relief and slope of the bed, and cover glaciers, in which the ice is so thick that it covers all the irregularities of the subglacial relief. Ice sheets are complex formations consisting of ice sheets, domes, ice streams, outlet glaciers and shelves. Ice covers are common on the islands - Novaya Zemlya, . Most of the territory of Eurasia lies in the path of cyclones coming from the northern part. Only glaciers and islands receive snow supply from Pacific cyclones.
The most common type of mountain glaciers are valley glaciers. They are divided into simple valley and complex valley (or dendritic), consisting of several glacial streams. In the mountains of Northern Russia and Siberia, cirque, cirque-valley and hanging glaciers are also common. Glacier regions in the European part of Russia include the Polar Urals and the northern part of the Greater Caucasus. In Siberia, these are the Altai Mountains, the Orulgan ridge, the Suntar-Khayata ridge, and the Koryak Highlands. There are glaciers on Taimyr and, and they are adjacent to volcanoes. Most of the glacial regions of Russia belong to the subpolar (subarctic) climate zone, and in the Caucasus and Altai - to the temperate one.
The total ice reserves on Earth today reach 25.8 million km3 (in water equivalent), which is two-thirds of the fresh water on our planet. Approximately 0.01% of this amount is renewed every year: 3.5 thousand km3 is annual accumulation-ablation, including iceberg calving, 20 thousand km3 is seasonal snow reserves, less than 0.5 thousand km3 is ice. Approximately 0.5 million km3 is covered by underground permafrost ice. The total ice reserves in Russia are more than 15,000 km3, of which only 183 km3 are on the mainland.
Glaciers are common in almost all mountainous regions of the country; they are found in all climatic zones: arctic, subarctic, temperate. The largest mountain glaciation is located at (992 km2), followed by the size of modern glaciation in the Altai Mountains (910 km2) and the Kamchatka Peninsula (874 km2). The smallest glaciers in area are the Urals and. The glaciated area in the Polar Urals is 28 km2, and in the Khibiny Mountains, on the Kola Peninsula, there are only four small glaciers with a total area of 0.1 km2.
The study of natural ice is necessary to solve problems associated with climate change and river flow, with hydropower, the study of fluctuations in the level of the World Ocean, irrigation of arid lands, combating natural disasters in the mountains, with the development of transport and the construction of various structures in polar and high-mountain regions.
As humanity's demand for fresh water grows, resources are becoming more prominent. This concept includes not only the snow and ice itself, their centuries-old reserves, but also the water from their melting.
In Russia, due to its geographical location, the main component of annual nival-glacial resources is snow reserves. Every year, snow covers the expanses of Russia for many months. Its maximum thickness varies from 25 cm in the south of the East European Plain to 1 m or more in Kamchatka, the Kola Peninsula and the north of Central Siberia. In the central regions, the snow thickness reaches half a meter. Stable snow cover, i.e., lying during the winter for at least two months, occupies the entire territory of Russia, except for the lower reaches of the Volga and Don rivers and the foothills of the North Caucasus.
One of the foundations of Russian agriculture, it is needed not only as a moisture storage device, but also as a reliable fur coat, covering the fields from the harsh winter. It represents the most important element, factor and indicator of climate change, since it depends simultaneously on precipitation and air temperature and, therefore, on the general nature of climate change. Snow cover affects the energy and water balance of the earth's surface, the flora and fauna of Russian open spaces.
Snow cover forms a specific link in the global moisture cycle - the exchange of water between the oceans occurs through the snow layer, in which moisture is retained for several months. All of Eurasia receives 75% of its snow from Atlantic moisture, 20% from Pacific moisture and 5% from . The ratio of the return flow of melt water is completely different. A significant part of the moisture goes into and only a little returns to the Atlantic.
Snow reserves on the territory of the Russian Federation in the middle and at the end of the twentieth century amounted to 2.3 thousand km3, and throughout Eurasia - 4.4 thousand km3. Thus, Russia's snow reserves account for more than half of the snow reserves of the Eurasian continent.
Fluctuations in annual snow reserves are generally relatively small and were not directly related to annual snow reserves during the study period. Global snow cover decreased during the warming period, but snow reserves in Eurasia did not decrease due to increased winter precipitation. The maximum snow reserves occurred in the early 80s of the last century. A comparison of average long-term data relating to the middle of the century, when a period of relative cooling was observed, and to the end of the century, when a period of climate warming began, which continues to this day, showed that despite the climate changes of recent years, snow reserves for most of the territory of Northern Eurasia remain relatively stable from year to year, but they are intensively redistributed over the area: volumes increase in the north and decrease in the south in years with relatively warm winters, and increase very significantly in the south in years with cold winters.
In modern conditions, there is no threat of a sharp decrease in snow reserves throughout the entire territory with corresponding consequences for the permafrost regime and the accumulation of moisture in the soil. But in some regions, catastrophic events are possible. Excessive accumulation and rapid melting of snow affects the dynamics of glaciers, as shown by the events of 2002 in the Genaldon River gorge in the Caucasus.
Nature is the greatest and most skillful of creators, revealing to us unprecedented beauty and grandeur in all her creations. For us, her masterpieces are truly a real miracle and nature has enough resources for creativity, be it stone, water or ice.
The Blue River is located on the Petermann Glacier (in the northwestern part of Greenland, east of Nares Strait), which is the largest in the entire northern hemisphere. It was discovered by three scientists who were conducting research on global climate change.
After its discovery, it began to attract a large number of tourists with its splendor, especially kayakers and kayakers who raft along it. An unusual river with crystal clear water is considered a symbol of a dying world and global warming, since due to the rapid melting of glaciers it becomes larger and larger every year.
Svalbard, meaning "cold coast", is an archipelago in the Arctic that makes up the northernmost part of Norway and Europe. This place is located approximately 650 kilometers north of continental Europe, halfway between mainland Norway and the North Pole. Despite its proximity to the North Pole, Svalbard is relatively warm thanks to the heating effect of the Gulf Stream, which makes it habitable.
In fact, Svalbard is the northernmost permanently inhabited area on the planet. The islands of Svalbard cover a total area of 62,050 square kilometers, almost 60% of which is covered by glaciers that extend directly into the sea. The giant Broswellbryn Glacier, located on Nordaustlandet - the second largest island in the archipelago, stretches for as much as 200 kilometers. The twenty-meter edges of this huge glacier are crossed by many waterfalls, which can only be noticed in the warmer seasons of the year.
This glacier cave is the result of ice melting when rain and meltwater on the surface of the glacier are directed into streams that enter the glacier through cracks. The flow of water gradually breaks through the hole, making its way to lower areas and forming long crystal caves. Fine sediments in the water give the stream a dirty color, while the top of the cave appears dark blue.
Due to the rapid movement of the glacier over the uneven terrain, approximately 1 meter per day, the ice cave becomes a deep vertical crevice at its end. This allows daylight to enter the cave from both ends.
Ice caves are located in unstable areas and can collapse at any time. They are only safe to enter in winter, when low temperatures harden the ice. Despite this, the constant sound of crunching ice in the cave can be heard. This is not because everything is about to collapse, but because the cave is moving along with the glacier itself. Every time the glacier moves a millimeter, extremely loud sounds can be heard.
The Briksdalsbreen glacier or Briksdail is one of the most accessible and best known branches of the Jostedalsbreen glacier in Norway. It is picturesquely located among the waterfalls and high peaks of the National Park of the same name. Its length is about 65 kilometers, its width reaches 6-7 kilometers, and the thickness of the ice in certain areas is 400 meters.
The tongue of the glacier, which has 18 shades of blue, descends into the Brixdale Valley from a height of 1,200 meters. The glacier is constantly in motion and ends in a small glacial lake, which is located 346 meters above sea level. The bright blue color of the ice is due to its special crystal structure and age of more than 10 thousand years. Glacial melt water is cloudy, like jelly. This is due to the presence of limestone in it.
Bearsday Canyon, carved by meltwater, is 45 meters deep. This photo was taken in 2008. Lines on the walls along the edge of Greenland's Ice Canyon show the stratigraphic layers of ice and snow that have formed over the years. The black layer at the base of the channel is cryoconite, a powdery, blown dust that is deposited and deposited on snow, glaciers or ice sheets.
Arctic glacier Elephant's Foot
The Elephant Foot Glacier is located on the Crown Prince Christian Land peninsula and is not connected to the main Greenland ice sheet. Multi-ton ice broke through the mountain and spilled into the sea in an almost symmetrical shape. It is not difficult to understand where this glacier got its name. This unique glacier clearly stands out among the surrounding landscape and is clearly visible from above.
This unique frozen wave is located in Antarctica. It was discovered by American scientist Tony Travoillon in 2007. These photos don't actually show the giant wave, somehow frozen in the process. The formation contains blue ice, which is strong evidence that it was not created instantly from a wave.
Blue ice is created by compressing trapped air bubbles. Ice appears blue because when light passes through the layers, blue light is reflected back and red light is absorbed. Thus, the dark blue color suggests that the ice formed slowly over time rather than instantly. Subsequent thawing and refreezing over many seasons gave the formation a smooth, wave-like surface.
Colored icebergs form when large chunks of ice break off an ice shelf and end up in the sea. When caught by the waves and carried away by the wind, icebergs can be painted with amazing bands of color in a variety of shapes and structures.
The color of an iceberg directly depends on its age. The newly calved ice mass contains a large amount of air in the upper layers, so it has a dull white color. Due to the replacement of air with droplets and water, the iceberg changes its color to white with a blue tint. When the water is rich in algae, the stripe may be colored green or another shade. Also, don’t be surprised by the pale pink iceberg.
Striped icebergs with multiple stripes of color, including yellow and brown, are quite common in the cold waters of Antarctica. Most often, icebergs have blue and green stripes, but they can also be brown.
Hundreds of ice towers can be seen at the top of Mount Erebus, which is 3,800 meters high. The permanently active volcano may be the only place in Antarctica where fire and ice meet, mix and create something unique. The towers can reach 20 meters in height and appear almost alive, releasing plumes of steam into the southern polar sky. Some of the volcanic steam freezes, depositing on the inside of the towers, expanding and expanding them.
Fang is a waterfall located near Vail, Colorado. A huge column of ice forms from this waterfall only during exceptionally cold winters, when the frost creates an ice column that grows up to 50 meters in height. Frozen Fang Falls has a base that reaches 8 meters in width.
Penitentes are amazing ice spikes formed naturally on the plains of the Andes at an altitude of over 4,000 meters above sea level. They are shaped like thin blades oriented towards the sun and reach heights ranging from a few centimeters to 5 meters, giving the impression of an icy forest. They slowly form as the ice melts in the morning sunlight.
People living in the Andes attribute this phenomenon to strong winds, which, in fact, are only part of the process. Research into this natural phenomenon is being conducted by several groups of scientists both in natural and laboratory conditions, but the final mechanism of the nucleation of penitentes crystals and their growth has not yet been established. Experiments show that the processes of cyclic thawing and freezing of water under conditions of low temperatures, as well as certain values of solar radiation, play a significant role in it.
Site materials used:
EAT. SINGER
Chief Specialist
Institute of Geography of the Russian Academy of Sciences,
Honorary polar explorer
The science of ice - glaciology (from the Latin glacies - ice and Greek logos - study) - originated at the end of the 18th century. in the Alpine mountains. It is in the Alps that people have lived near glaciers since time immemorial. However, only in the second half of the 19th century. researchers became seriously interested in glaciers. Nowadays, in addition to glaciers, glaciology studies solid sediments, snow cover, underground, sea, lake and river ice, aufeis, and it has begun to be perceived more broadly - as the science of all types of natural ice existing on the surface of the Earth, in the atmosphere, hydrosphere and lithosphere. Over the past two decades, scientists have viewed glaciology as the science of natural systems whose properties and dynamics are determined by ice.
Historically, glaciology grew out of hydrology and geology and was considered a part of hydrology until the mid-20th century. Nowadays, glaciology has become an independent branch of knowledge, lying at the intersection of geography, hydrology, geology and geophysics. Together with permafrost science (otherwise known as geocryology), which studies permafrost, glaciology is part of the science of the cryosphere - cryology. The Greek root "kryo" means cold, frost, ice. Currently, methods of physical, mathematical, geophysical, geological and other sciences are widely used in glaciology.
The essence of modern glaciology consists of problems caused by understanding the place and significance of snow and ice in the fate of the Earth. Ice is one of the most common rocks on our planet. They occupy more than 1/10 of the land area of the globe. Natural ice significantly influences the formation of climate, fluctuations in the level of the World Ocean, river flow and its forecast, hydropower, natural disasters in the mountains, the development of transport, construction, organization of recreation and tourism in polar and high-mountain regions.
On the surface of the Earth, snow cover, glaciers, underground ice are formed annually or constantly exist... They occupy an area from a fraction of a percent in the tropics to 100% in the polar regions, where they especially significantly influence the climate and the surrounding nature.
The purest and driest snow covering glaciers reflects up to 90% of the sun's rays. Thus, more than 70 million km 2 of snow surface receive much less heat than areas without snow. This is why snow greatly cools the Earth. In addition, snow has another amazing property: it intensely emits thermal energy. Thanks to this, the snow cools even more, and the vast expanses of the globe covered by it become a source of global cooling.
Snow and ice form a kind of earthly sphere - the glaciosphere. It is distinguished by the presence of water in the solid phase, slow mass transfer (complete replacement of ice in glaciers occurs as a result of the circulation of matter on average in about ten thousand years, and in Central Antarctica - in hundreds of thousands of years), high reflectivity, a special mechanism of influence on land and the earth's crust. The glaciosphere is an integral and independent part of the planetary system “atmosphere - ocean - land - glaciation”. Unlike land, seas, inland waters and the atmosphere, the snow-ice sphere in the past completely disappeared at some stages of the Earth's history.
Ancient glaciations were caused by a cooling of the Earth's climate, which has undergone repeated changes throughout its history. Warm times, which contributed to the development of life, were followed by periods of severe cold weather, and then huge ice sheets occupied vast areas of the planet. Throughout geological history, glaciations have occurred every 200-300 million years. The average air temperature on Earth during glacial eras was 6-7 °C lower than during warm eras. 25 million years ago, during the Paleogene period, the climate was more homogeneous. In the subsequent Neogene period, a general cooling occurred. Over the past millennia, large glacial formations have been preserved only in the polar regions of the Earth. The Antarctic ice sheet is believed to have existed for more than 20 million years. About two million years ago, ice sheets also appeared in the Northern Hemisphere. They changed greatly in size, and sometimes disappeared altogether. The last major glacial advance occurred 18-20 thousand years ago. The total area of glaciation at that time was at least four times greater than today. Among the reasons causing changes in glaciation over tens of millions of years, Academician V.M. Kotlyakov puts the transformation of the outlines of continents and the distribution of ocean currents, caused by continental drift, in the first place. The modern era is part of the Ice Age.
If for a person far from glaciology, the concept of “last year’s snow” usually means something that no longer exists, incredible, or simply an empty or funny phenomenon, then any glaciologist and even a geography student knows that if it weren’t for last year’s snows, there would not have been and the glaciers themselves.
Every year, trillions of tons of snow fall from the atmosphere onto the surface of our planet. Every year in the Northern Hemisphere, snow cover covers a huge area of almost 80 million km2, and in the Southern Hemisphere it covers half as much.
Snow is born in clouds where the relative humidity reaches 100%. The higher the air temperature at which countless varieties of snowflakes are born, the larger their sizes. The smallest snowflakes occur at low air temperatures. At temperatures close to zero degrees, large flakes are usually observed, which are formed as a result of the freezing of individual small snowflakes.
But atmospheric crystals were deposited on the earth's surface and formed a snow cover on it. Its density and structure are significantly affected by air temperature and wind. Higher temperatures cause snow particles to stick together and create a very compact mass. A strong wind can lift and transport snow in the ground layer from one place to another, turning it into tiny fragments that are already deprived of beautiful openwork rays. The stronger the wind, the more snow it will remove from the surface, the more densely it will pack it.
But snow particles cannot travel indefinitely: they will press tightly together and freeze into a solid snowdrift or eventually evaporate. Over the course of several hours, the storm wind creates very dense ridges - sastrugi, which a person’s foot cannot push through.
Winter is passing. The sun rises higher and higher above the horizon. Its spring rays try to melt the snow that has accumulated during the cold season. However, snow begins to melt only when warm air can heat it to zero temperature. Since a very large amount of heat is spent on melting, the air in snow-covered regions of the Earth warms up much more slowly and its temperature continues to remain relatively low for a long time. In the Antarctic and Arctic, as well as on the high mountains of the temperate zone of the planet, the meager summer melting is usually not enough to melt all the seasonal snow in a short time. With the onset of another winter, a new layer is deposited on the remnant of last year’s snow, and after another
year - another. This is how huge masses of perennial snow - firn - are gradually accumulated and compressed. Ice forms from its layers over time. Having reached a certain thickness, it begins to move extremely slowly down the slope. Once in a warmer zone, the mass of ice “unloads” - melts. This is a rough diagram of the origin of a glacier. Explanatory glaciological dictionary under the word glacier understands a mass of ice formed primarily from solid atmospheric precipitation, undergoing visco-plastic flow under the influence of gravity and taking the form of a stream, stream system, dome or floating slab. There are mountain glaciers and cover glaciers.
A glacier exists in conditions where more solid atmospheric precipitation accumulates above the snow line than will melt, evaporate, or be consumed in any other way. There are two regions on glaciers: the region of feeding (or accumulation) and the region of discharge (or ablation). Ablation, in addition to melting, also includes evaporation, wind blowing, ice collapse and iceberg calving. Glaciers move from the supply area to the discharge area. The height of the snow line can vary over a very wide range - from sea level (in the Antarctic and Arctic) to a height of 6000-6500 meters (in the Tibetan Plateau). At the same time, in the very north of the Ural Range and in some other areas of the globe there are glaciers that are located below the climatic snow line.
The sizes of glaciers can be very different - from fractions of a square
kilometers (as, for example, in the north of the Urals) to millions of square kilometers (in Antarctica). Thanks to their movement, glaciers carry out significant geological activities: they destroy underlying rocks, transport and deposit them. All this causes significant changes in relief and surface height. Glaciers change the local climate in a direction favorable to their development. Ice “lives” inside glaciers for an unusually long time. The same particle of it can exist for hundreds and thousands of years. Eventually it will melt or evaporate.
Glaciers are one of the most important components of the Earth's geographic envelope. They cover about 11% of the globe's area (16.1 million km2). The volume of ice contained in glaciers is approximately 30 million km 3 . If it were possible to spread it in an even layer over the surface of the globe, the thickness of the ice would be approximately 60 m. In this case, the average air temperature on the surface of the Earth would become much lower than it is now, and life on the planet would cease. Fortunately, such a prospect does not threaten us today. If we nevertheless imagine instantaneous global warming, which is absolutely incredible in our days, which would entail the simultaneous rapid melting of all the Earth’s glaciers, then the level of the World Ocean would rise by approximately 60 m.
As a result, densely populated coastal plains and major seaports and cities would be under water over an area of 15 million km 2. During past geological epochs, sea level fluctuations were much greater, and ice sheets formed and then melted. The largest fluctuations of glaciers led to alternation of glacial and ice-free periods. The average thickness of modern glaciers is about 1700 m, and the maximum measured exceeds 4000 m (in Antarctica). It is due to this icy continent, as well as Greenland, that the average thickness of modern glaciers is so high.
Nowadays, glaciers are distributed very unevenly due to different climatic conditions and topography of the earth's surface. About 97% of the total area of glaciers and 99% of their volume are concentrated in two colossal sheets of Antarctica and Greenland. Without these natural refrigerators, the earth's climate would be much more uniform and warmer from the equator to the poles. There would not be such a variety of natural conditions as we have now. The existence of vast ice caps in the Antarctic and Arctic increases the temperature contrast between the Earth's high and low latitudes, resulting in more vigorous circulation of the planet's atmosphere. Antarctica and Greenland play in our time one of the main roles in shaping the climate of the entire globe. Therefore, both largest areas of modern glaciation are sometimes figuratively called the main conductors of the Earth's climate.
Glaciers are sensitive indicators of climate change. By their fluctuations, scientists judge its evolution. Glaciers perform gigantic geological work. For example, as a result of the enormous load of large ice sheets, the earth's crust bends to a depth of hundreds of meters, and when this load is removed, it rises. The widespread reduction of glaciers over the past 100-150 years is consistent with global warming (about 0.6 °C over the same period). The former sizes of glaciers can be reconstructed by the position of their moraines - shafts of rock fragments deposited during glacial advances. By determining the time of formation of moraines, it is possible to determine the time of past glacial movements.
Glaciers are the most important water resources on the planet. Ice is a monomineral rock that is a special, solid phase of water.
The purest water in the world is carefully stored in the richest ice reserves on the planet. Its amount is equal to the flow of all the world's rivers over the past 650-700 years. The mass of glaciers is 20 thousand times greater than the mass of river waters.
Humanity still does not know enough about solid water storage facilities. In order to study them at the Institute of Geography of the USSR Academy of Sciences in the 60-70s under the guidance of prof. V.M. Kotlyakov, a huge amount of work was done to create a multi-volume series of a unique glaciological work - “Catalog of Glaciers of the USSR”. It provides systematized information about all glaciers of the USSR, indicating the main characteristics of their size, shape, position and regime, as well as the state of knowledge.
In addition to significantly influencing the climate, glaciers affect the lives and economic activities of people living in their vicinity. Man is forced to reckon with the unbridled nature of glaciers. At times they awaken and pose a formidable danger. Enormous accumulations of snow and ice in the mountains often give rise to such natural phenomena as mudflows - mudflows, avalanches, sudden movements and collapses of the terminal sections of glaciers, dams of rivers and lakes, floods and freshets.
Everyone is hearing about the recent catastrophic movement of the Kolka glacier in North Ossetia.
Pulsating glaciers exist in many areas of the Earth. A large number of them have been identified in North and South America, Iceland, the Alps, the Himalayas, Karakorum, New Zealand, Spitsbergen, the Pamirs, and the Tien Shan. On the territory of Russia they are found in the mountains of the Caucasus, Altai, and Kamchatka. A significant number of pulsating glaciers end up moving in the coastal waters of the Arctic and Antarctic. Fluctuations in polar ice caps serve as a reliable natural indicator of global climate change. It is impossible to fight icy “pulsars”. It is much more important to learn how to correctly predict their movement.
Numerous observatories and scientific stations have been created in various regions of the globe, where, in the most difficult natural and climatic conditions, researchers conduct observations on glaciers, study their characteristics and habits. The proximity to glaciers is fraught with both benefits and dangers. On the one hand, they supply people and their households with drinking and technical water, and on the other, they create additional troubles and simply a threat, since they can be sources of disasters. Therefore, today glaciological research is of direct national economic importance, and qualified advice from glaciological scientists is already required when solving important problems related to the development of hydropower, mining and construction in the mountains and polar regions. Thus, in addition to the purely scientific, glaciology has recently acquired great practical significance, which will increase in the future. The role of glaciology is constantly growing, since more and more new areas with long-lasting snow and ice cover and a harsh climate are involved in social production. In Russia, this is the northern coast of the country, washed over a vast distance by the Arctic Ocean, the endless expanses of Siberia, the highlands of the Caucasus, Altai, Sayan, Yakutia, and the Far East.
Systematic study of glaciers began relatively recently. It began to develop especially intensively in the late 50s. July 1, 1957 went down in world history as the beginning of a grandiose scientific event - the International Geophysical Year (abbreviated IGY). Thousands of scientists from 67 countries of the Old and New Worlds then joined forces to carry out comprehensive studies of global geophysical processes during the period of maximum solar activity under a single program. For the first time, glaciology became one of the main branches of the study of the Earth. Over 100 glacier stations operated during the IGY from the North to the South Pole. Thanks to this, our knowledge of modern glaciation of the globe has expanded significantly. After the completion of the IGY, glaciological science received universal recognition among other planetary sciences.
The time has come when glaciologists from different countries began comprehensive research on the enormous ice sheets of Antarctica and Greenland, on the polar archipelagos and islands, and in the highlands of the Earth. The glaciation of the Antarctic and Arctic, unlike the glaciation of temperate latitudes, directly interacts with the ocean. The flow of ice into the ocean remains the most unexplored process and one of the most important from the point of view of glaciology of global and regional changes in climate and natural environment in the Arctic.
Today, glaciology has accumulated a huge amount of factual material about the natural ice of the Earth. For many years, under the leadership of Academician V.M. Kotlyakov at the Institute of Geography of the USSR Academy of Sciences (now the Russian Academy of Sciences) painstaking work was carried out to create a unique Atlas of snow and ice resources of the world; in 1997 it was published, and in 2002 it was awarded the State Prize of the Russian Federation. This unique collection of numerous maps reflects the state of snow-glacier objects and phenomena for the period of the 60-70s of the 20th century. All of them are necessary for comparison with their subsequent changes under the influence of both natural and anthropogenic factors. The atlas makes it possible to qualitatively, and in some cases quantitatively, assess the significance of snow and ice phenomena at all levels - from the river basin to the “atmosphere - ocean - land - glaciation” system, and to calculate the reserves of snow and ice as an important part of water resources. Modern scientific knowledge about the formation, distribution and regime of snow and ice on Earth, presented in the Atlas, opens up broad prospects for the development of glaciological and related branches of science about our planet and contributes to the further development of many territories of the globe. The extensive glaciological materials accumulated over the past decades allow glaciologists to come closer to solving a number of pressing theoretical issues in glaciation.
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In everyday life, the verb “to fly over” is used much less often than “to overwinter.” Glaciologists use it very widely. Patches of snow on the slopes that existed before the formation of snow cover are called flights(not flights!). - Here and further approx. ed.
See: K.S. Lazarevich. Snow line//Geography, No. 18/2000, p. 3.
For more details see: E.M. Singer. Miniature glaciers of the Urals // Ibid., p. 4.
See: N.I. Osokin. Glacial disaster in North Ossetia // Geography, No. 43/2002,
With. 3-7.
Municipal educational autonomous institution
"Lyceum No. 6" named after Z. G. Serazetdinova
Lesson summary on geography 8th grade on the topic:
"NATURAL ICE"
Author of the methodological development
Geography teacher
first qualification category
Inozemtseva Elena Alexandrovna
Orenburg, 2014
Goals:
person.
people, the ability to listen to the opinions of others.
Lesson type: combined.
Equipment: 1. Atlas maps for class 89 ed. "Cartography",
2. Multimedia presentation “Natural ice and the great glaciation”
Russia."
3. Textbook by E. M. Domogatskikh, N. I. Alekseevsky, N. N. Klyuev,
Moscow, “Russian Word” 2014
Lesson time distribution:
1.
2.
3.
4.
5.
6.
Organizational moment – 1–2 min.
Updating basic knowledge – 5 min.
Goal setting, motivation – 2 min.
Primary assimilation of the material – 25 min.
Consolidation – 78 min.
Analysis, reflection – 2 min.
I.
Organizing time
During the classes
Greetings. The teacher offers to determine readiness for the lesson, creates
positive attitude.
II.
Updating basic knowledge testing knowledge on the topic “Lakes and swamps”
Russia"
What is a lake? Give examples
What types of origin of lakes are distinguished? Examples
What types of lakes are distinguished by salinity? How to recognize them on the map? Lead
example
Name the world record holders and explain the reason for their record-breaking.
III. Goal setting, motivation
U: I would like the topic of today’s lesson to start with this riddle:
It's cold and shiny
If you hit it, it will immediately crunch.
It takes its kin from the water,
Well, of course it is... (ice)
So, what do you think the lesson will be about today? Slide No. 1
T: The objectives of our lesson today will be the following:
Introduce the types of natural ice, find out the meaning of the concept “perennial
permafrost", analyze the distribution of permafrost in the territory
Russia, to find out the impact of permafrost on economic activity
person.
Develop skills in working with maps, analyzing the information received,
be able to obtain information from various sources.
To instill in students feelings of patriotism and respect for others
people, the ability to listen to the opinions of others. Slide No. 2
IV. Primary assimilation of material
Russia is a country located entirely in the northern hemisphere. It means that
in our country the air temperature drops below zero for long periods
months. There are areas of our country where the temperature remains negative throughout
whole year. This is the reason for the existence of various natural ices. Slide
№3
There are two types of natural ice: surface and underground
In winter, water in the top layer of soil freezes and turns into solid
monolith. Ice can freeze rivers and lakes for a certain season (at negative
temperatures), which allows us to talk about seasonal ice (i.e. they exist only in
cold season and in the spring there will be nothing left of them). but there are ices that are not
melt throughout the year. Such ice is called multi-year ice. Possible in regular
in life we often hear the expression “eternal snow”, but from a scientific point of view it is correct
say "perennial". Since nothing is eternal in our lives, it would be strange
hear the phrase “The eternal snows have melted.”
Since the earth's crust is composed of rocks, frozen rocks
many years form another phenomenon - permafrost (the upper layer of the earth's
crust, which has year-round negative temperatures). Ice plays a role in soil
“cement” and tightly holds soil particles together. In areas of sharply continental
climate, where there are very low temperatures and thin snow cover that does not protect
salary cooling results in soil freezing (during a short summer, only
top layer of soil), the bottom layer of soil always remains frozen. T remains
preserved permafrost even thousands of years after the destruction of the great
glacier. Slide No. 4
U: In Russia, the total area of permafrost = 65% of the entire territory of Russia. (This
almost 11 million km2).
Based on the scale of permafrost distribution, its types are distinguished:
A) Solid
B) Island
B) Intermittent distribution zone Slide No. 5
Task No. 1 Fill out the table in your notebook with subjects of the Russian Federation and natural complexes, where
each type of permafrost is traced (using Fig. 95, page 156 in the textbook, atlas
map “Federal structure” and physical map of Russia) Slide No. 6,7
U: Let's try to understand how permafrost affects a person's health?
(students give their answers) Slide No. 8
U: Do you remember that with altitude the temperature decreases and the altitude above which
it does not rise above zero is called the snow line. In different parts of the west.