Perhaps there is no place in the world more mysterious than Antarctica. The vast expanses of ice could tell a lot about what the Earth was like millions of years ago. But nature is in no hurry to reveal its secrets, and man comes back here again and again, fighting the cold and the blizzard.
Antarctica is the ice heart of Antarctica: on an area of 13 million 661 thousand km 2 there are 30 million km 3 of ice! The geographic South Pole, the Pole of Cold (- 89.2 ° C - the lowest temperature), the Pole of Inaccessibility, conquered by the Soviet expedition in 1958, the South Geomagnetic Pole pass through the mainland.
The mainland does not belong to any of the countries. In Antarctica, you cannot develop minerals or carry out industrial work - only scientific activities are allowed, therefore, in addition to seals and penguins, scientists from different countries inhabit the mainland. Only well-trained people, strong in spirit and body, live and work here. The reason for this is the extreme conditions and the harsh climate.
Features of the climate of Antarctica
The warmest time on the mainland is from November to February - spring and summer in the Southern Hemisphere. On the coast, the air can warm up to 0 ° С, and near the cold pole, the temperature rises to -30 ° С.
Summer in Antarctica is so sunny that in no case should you forget about sunglasses - you can seriously damage your eyes. And you can't do without lipstick either - lips instantly crack without it, and it's impossible to eat or speak. Why, then, is it so cold and the glaciers are not melting? Almost 90% of solar energy is reflected from ice and snow cover, and if we consider that the continent receives solar heat mainly in summer, it turns out that during the year Antarctica loses more heat than it gains.
The lowest temperature is from March to October, autumn and winter in Antarctica, when the thermometer drops to -75 ° C. This is the period of the strongest storms, planes do not arrive on the mainland, and polar explorers are cut off from the rest of the world for a long 8 months.
Polar day and polar night in the Southern Hemisphere
Photo of the aurora near McMurdo Station, July 15, 2012
In Antarctica, as well as in the Northern Hemisphere, there is a polar night and a polar day, which last around the clock. If we rely only on astronomical calculations, then on December 22, the day of the summer solstice in the Southern Hemisphere, the sun at midnight should only half hide behind the horizon, and then rise again. And on June 22, on the day of the winter solstice, only half appear on the horizon at noon, and then disappear. But there is astronomical refraction - an optical phenomenon associated with the refraction of light rays. Thanks to refraction, we see the stars before they appear above the horizon, and for some time after they have set. Therefore, the usual change of day and night occurs only in spring and autumn. The polar night reigns in winter, and the polar day in summer.
Antarctica nature
A kind of visiting card of Antarctica is the penguin. Several species of these funny birds live here: on the continental coast - emperor, royal, gentoo penguin, Adélie penguin. And on the Antarctic and subantarctic islands, crested, arctic, macaroni penguins live.
There are other birds: petrels (Antarctic, snow, silver-gray), skuas,
Antarctica is a habitat for several species of seals: Weddell seal, Ross seal, crabeater seal, southern elephant seal, leopard seal, Kerguelen fur seal.
Whales live here: blue whale, flat-faced bottlenose, sperm whale, killer whales, sei whale, southern minke.
It's hard to imagine, but even here, on the icy continent, there is vegetation. Lichens, grasses and cloves, whose height does not exceed 1 cm, and some types of moss, hide in the crevices of the rocks.
Polar stations in Antarctica
The photo shows a view of the McMurdo station in Antarctica, November 2011
Most of the stations are located in the coastal zone of the continent, and only three of them are inland. These are the American Amundsen-Scott base, the Franco-Italian Concordia and the Russian Vostok base.
An interesting story is connected with the opening of Vostok. When in the early 50s at a meeting in Paris, the issues of the development of Antarctica were being resolved, our delegation was tasked with proving by all means that the Soviet Union had enough resources to maintain the operation of the station at the South Geographic Pole itself. But due to delays with passports and visas, our delegate was late for the beginning of the meeting, and this place had already been promised to the Americans. We got the South Geomagnetic Pole and the Pole of Inaccessibility. In 1957, the Vostok scientific station was founded at the South Geomagnetic Pole. And 50 years later, scientists managed to get a sample of the water from an underground lake, located, as it turned out, right under the station! Fifth by volume of fresh water, hidden under ice at a depth of almost 4,000 m, Lake Vostok sheds light on the origin of the Earth and life on Earth. This is incredible luck!
Photo shows a spring sunset near Palmer Arctic Station, March 31, 2011
In total, there are 5 Russian bases in Antarctica, operating all year round: Bellingshausen, Mirny, Vostok, Progress, Novolazarevskaya. Scientists study the atmosphere, weather, ice, movement of the earth's crust. All bases offer the most comfortable conditions: in addition to everything necessary for work, there are rest rooms, a gym, billiards, and a library. IP-telephony and Internet access have been established, broadcasting of 1 channel is broadcast.
The closest neighbors of the scientists from the Novolazarevskaya base are specialists from India. The name of their base - "Maitri" - means "friendship" and best describes the relationship between polar explorers. By the way, a warm, friendly atmosphere has always been here. Even during the Cold War, scientists carried out joint research, used the best practices of each other.
In the photo of the satellite communications dish at the McMurdo station in Antarctica
In addition to traditional holidays, the bases celebrate the beginning and end of each expedition. At the gala dinner, a symbolic transfer of the key from the station takes place. Despite a quick meeting with relatives, scientists leaving the station involuntarily envy those who stay for the winter - Antarctica does not let go. Cold, stormy, but so beautiful.
The climatic conditions of Antarctica are harsh due to the polar location of the continent. Rarely does the air temperature rise above 0 degrees Celsius on the continent. Antarctica is completely covered by thick glaciers. The mainland is under the influence of cold air masses, namely, the westerly winds. In general, the continent's climatic conditions are arid and harsh.
Antarctic climate zone
Almost the entire territory of the continent is located in the Antarctic climatic zone. The thickness of the ice cover exceeds 4500 thousand meters, in connection with which Antarctica is considered the highest continent of the Earth. More than 90% of solar radiation is reflected from the ice surface, so the mainland practically does not warm up. There is practically no precipitation, and there are no more than 250 mm of precipitation per year. The average daytime temperature is -32 degrees, and the nighttime is -64. The temperature minimum is fixed at -89 degrees. Strong winds move over the mainland with high speeds, increasing on the coast.
Subantarctic climate
The climate of the subantarctic type is typical for the northern part of the continent. Tendencies of softening of weather conditions are noticeable here. There is twice as much precipitation here, but it does not exceed the annual rate of 500 mm. In summer, the air temperature rises slightly above 0 degrees. In this area, the ice is slightly less and the relief turns into rocky terrain, covered with lichens and mosses. But the influence of the continental arctic climate is significant. Therefore, there are strong winds and frosts. Such weather conditions are absolutely not suitable for human life.
Antarctic oases
On the coast of the Arctic Ocean, different from continental weather conditions have formed. These areas are called Antarctic oases. The average summer temperature is +4 degrees Celsius. Parts of the mainland are not covered with ice here. In general, the number of such oases does not exceed 0.3% of the total area of the continent. Here you can find Antarctic lakes and lagoons with high salt levels. One of the first open Antarctic oases was the Dry Valleys.
Antarctica has unique climatic conditions as it is located at the South Pole of the Earth. There are two climatic zones - Antarctic and Subantarctic, which are distinguished by the most severe weather conditions, in which there is practically no vegetation, but some species of animals and birds live.
The material contains information about the climatic zones in which the mainland lies. Tells about the history of the development of the continent. Explains the reason for climate change.
Antarctica is an extremely harsh continent of the globe by climatic standards. Almost the entire continental surface lies in the range where the air temperature does not rise above zero degrees. This is due to the presence of the Antarctic Plate at the South Pole.
Antarctica hasn't always been like this. During the Mesozoic period, when Pangea was still at the split stage, the planet's climate was humid and warmer.
Rice. 1. Pangea.
Millions of years later, mainland lands fell into the subpolar region of the earth's surface. This caused the glaciation of Antarctica and marked the beginning of a cold snap throughout the planet. This is clearly expressed in the territories of the Southern Hemisphere.
Then there were other changes on a planetary scale.
Cold currents began to form around Antarctica under the influence of westerly winds. These processes were expressed in a general cooling throughout the planet, glaciation of the polar regions, the emergence of vast desert regions. The climate acquired more severe features, and at the same time became arid.
In what climatic zones is the territory of Antarctica located?
Two climatic zones pass through Antarctica:
- Antarctic;
- subantactic.
At times, the area of the northern part of the Antarctic Peninsula is referred to as the temperate zone.
Rice. 2. Climatic zones of Antarctica.
The Antarctic belt dominates almost all continental zones. The ice shell that covers this area is up to 4500 thousand meters thick. Thanks to this, Antarctica is the highest continent on the planet. Ice on the mainland serves as a climate-forming component. The ice crust reflects up to 90% of the sun's rays. This factor prevents the Sun from warming up the surface of the continent. The climate is extremely harsh in the continental regions of Antarctica. There is almost never rainfall.
In certain places, the total rainfall is less than 50 mm. per calendar year. In the main zone of the belt, this figure is less than 250-100 mm.
The temperature amplitude in the interior of the continent during the polar night can drop to minus 64 ° C. In summer, when the sun does not set, the temperature is close to minus 32 ° C. The pole of inaccessibility of the planet passes here.
Rice. 3. Icy deserts.
At the Vostok polar station, an extremely low temperature of minus 89 ° C was noted.
The subantarctic belt runs along the northern part of the peninsula. The natural conditions in this area are somewhat milder. The amount of precipitation reaches over 500 mm. in year. In summer, temperatures rise above 0 ° C. The ice crust in these areas is much thinner and in places turns into bare rocks, which are covered with mosses and lichens.
What have we learned?
We found out what factors influenced abrupt climate changes over millions of years. We learned about the critical temperature values. We studied the climatic zones of Antarctica and remembered that there are only two of them - arctic and subarctic.
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One of the reasons for the harsh climate of Antarctica is its height (the highest continent on the planet). As you know, with height, the air temperature near the Earth's surface drops by an average of 0.6 ° C for every 100 m of rise. In this regard, Antarctica should be colder than any continent by 6-7 ° C. However, the primary cause of glaciation is not height, but the geographic position of the circumpolar sixth continent: the farther from the equator to the pole, the less solar heat a unit of the Earth's surface receives due to the greater inclination of the sun's rays. An additional reason for the cooling is the land around the pole, not the ocean. The soil absorbs 70% of the solar radiation, and the ocean more than 90%. The snow-ice surface of Antarctica absorbs only 10 - 20% of solar radiation; It reflects 90% of the sun's rays into space like a giant mirror.
A very cold layer of air is formed over the glacial surface of Antarctica, in which the temperature does not fall with height, but increases, i.e., there is a temperature inversion (unlike all other continents of the Earth). Heavy cold air from the central regions of the mainland spreads in all directions along the slopes of the ice sheet, forming a drain wind. The loss of air over the center of the continent is replenished by the influx of new air masses from the higher layers of the atmosphere. Air masses from adjacent latitudes enter the high layers. Downward circulation is created, a typical anticyclonic process, which is accompanied by drying out of the air. The absence of cloud cover contributes to the further cooling of the continent. The 10% of the solar energy that the surface of Antarctica absorbs is also mainly spent in space. Like any body heated above absolute zero, snow radiates heat in the form of infrared waves. Since there are no clouds over the central regions of Antarctica, this long wavelength radiation freely escapes into space.
By the nature of the climate in Antarctica, the following are distinguished: the inland high-mountainous region, the glacial slope and the coastal zone. The glacial plateau is characterized by extreme frosts, a polar anticyclone, a predominance of clear weather, a small amount of precipitation falling all year round in the form of snow (30-50 mm / year). The center of the continent is located here - the Pole of relative inaccessibility. The circumpolar zone of the glacial slopes, along which the paths of the glacial runoff diverge fan-likely from the high-mountainous massifs, has a width of 700-800 km. Average monthly temperatures in the zone range from 50 ° C in winter to 30 ° C in summer. Low temperatures are combined with constant winds blowing from high mountain ranges and blizzards. Precipitation in the form of snow falls 100-250 mm / year. The narrow coastal zone receives up to 700 mm of precipitation mainly in the form of snow. In winter, average monthly temperatures range from 8 to -35 ° С, in summer from 0 to + 2 ° С. The usual wind speed is 50-60 m / s.
The climate of any place on earth, like climate of Antarctica, is formed under the influence of three main factors: solar radiation, atmospheric circulation and geographic conditions of the place itself... Mainland Antarctica.
Mainland Antarctica
It is known that where the earth receives a lot of solar heat, as, for example, at the equator, it is always hot; where air currents bring moist sea air, damp; it is cold and snowy at the top of the high mountain, and eternal summer stands at its foot. But on Earth there are places and even a whole continent where in summer almost as much solar heat falls on its surface as in the subtropics. However, not only grapes do not ripen here, but even grass does not grow. The land is covered with a thick layer of snow and ice that does not melt even in summer. This is mainland Antarctica... On a clear summer day on the coast, each square centimeter of the surface receives about 0.5 calories of solar heat in one minute. The sum of incoming heat in one summer month is almost 20 thousand calories (20 large calories). This is one and a half, even two times more than at the same latitudes of the northern hemisphere, and only slightly less than what the cotton fields near Tashkent get. If all this heat was spent here on melting, then in one summer its power would decrease by ten meters, that is, in 10-15 years in the region Mirny(located on the coast of Antarctica) the ice would completely melt.
Glacier on the coast of Antarctica. Inland, for example at a station Pionerskaya, even more solar heat comes to the surface of the snow in summer, but the snow does not melt. Eternal frost and blizzard reign here. Why is this happening? Where does all this huge amount of solar energy go? After all, according to the law of conservation of energy, it should not disappear anywhere! .. Antarctic climate mystery
It was the main mystery of the climate of Antarctica. To solve it, the members of the first Soviet Antarctic expedition, which was based at Mirny and Pionerskaya stations, throughout the year continuously monitored the arrival and consumption of solar heat, that is, they kept a kind of "bookkeeping" of solar radiation. Most of this work was performed by special recorders - "electromechanical" bookkeepers of the Sun ". They continuously recorded how much heat comes from the sun, how much it is reflected and emitted by the snow-ice surface of Antarctica, and, finally, what is the radiation balance.Antarctica Climate Research
results Antarctic climate research exceeded all expectations. It turned out that about 80-82% of the sun's rays falling on it are reflected from the snow-ice surface of Antarctica, like from a mirror, in winter and summer. This huge amount of solar energy goes back almost completely back into space.
Snow-icy climate of Antarctica. Well, where are the remaining 18-20% of the sun's rays falling on the earth? They are absorbed by the earth's surface and converted into heat. But even this, already assimilated heat, the surface of Antarctica cannot save. Almost half of it (more than 10% of the total radiation) is lost by thermal radiation, and only the remaining 8-10, and even 5% on Pionerskaya is spent by Antarctica for its needs. But it happens in summer(from November to February). In winter(from March to October) the surface of Antarctica receives practically no solar heat at all. And the radiation of heat from its surface occurs continuously. Heat loss every month due to radiation in winter is 2-3 large calories. Calculations show that due to radiation, the surface of Antarctica would be cooled by about 5-6 ° per hour. However, this does not happen. Only once, while exploring the climate of Antarctica, the participants of the first expedition, which arrived in Antarctica in January 1956, witnessed such a sharp drop in temperature. It was August 20, in the middle of the most severe winter month. The sewage wind usually beginning in the evening (the wind flowing down from the snowy peaks of the mainland) suddenly died down. It quickly became clear, and the temperature dropped by 10 ° within an hour and a half, reaching -40.4 °. This was the lowest temperature in Mirny. Then the wind blew and again it became warmer on the southernmost land. Influence of air circulation on the climate of Antarctica
So the movement air circulation saves the surface of Antarctica from continuous cooling. The influence of atmospheric circulation on the formation of the Antarctic climate is extraordinarily great. In Mirny, for example, there was not a single winter month, so that the air temperature with the arrival of the sea air mass would not rise to -3 -6 °. So, for example, from April 29 to April 30 of the study year, during the day the temperature increased from -25 to -8 °. Such warming spread even to Pionerskaya, where over the same day the temperature increased from -50 ° to -30 °. Warm periods in Antarctica in winter sometimes last for a week or more. In this case, heat transfer from the air to the underlying surface occurs not only by air vortices, but also by thermal radiation of the atmosphere. The surface of Antarctica, instead of radiating heat, begins to receive it from the atmosphere, the radiation balance becomes positive and the temperature begins to rise rapidly. Due to the circulation of the atmosphere, not only heat is brought to the shores of Antarctica, but also cold. This happens when the air moves not from the sea, but from the depths of Antarctica, flowing down the slope of the Antarctic plateau.
The cold off the coast of Antarctica is not a hindrance to hunting penguins. As water, after a heavy rain that fell on the side of a mountain, flows down to the foot, rapidly accelerating its movement under the influence of gravity, so cooled, denser air descends along the long slope of the Antarctic glacial plateau. It moves faster and faster every minute, often reaching the strength of a hurricane near the coast. However, unlike the flow of water, the air flowing down the slope is continuously heated (for every 100 m of height by 1 °), so the temperature from which it comes to the coast, although low, is much higher than that which would be here if there would be no wind. This is confirmed by data from remote stations. So, for example, on a clear day on August 12, when a storm was raging in Mirny, 13 km from it on the fast ice (this is the name of the ice above the water surface, firmly adhered to the mainland ice), where the influence of the sewage wind was not affected, there was calm and temperature air was 11 ° lower than in Mirny. The sewage wind in Antarctica is a "cold" hair dryer. The air moving from the central regions of Antarctica, as with an ordinary hair dryer, heats up and, moving away from the saturation point, becomes drier. However, due to relatively low altitudes and very low initial temperatures, it cannot get very hot, therefore it comes to the coast not warm, but cold. For example, such a case: the air moves from the Pionerskaya station to Mirny. The difference in altitude between these stations is about 3 km. If the air temperature on Pionerskaya was -50 °, then it will come to Mirny with a temperature of -20 °, that is, it is still very cold. The circulation of the atmosphere over Antarctica is completely peculiar.... In coastal areas, and far inland, the whole year winds blow from almost one sector (from the northeast to the southeast), but depending on whether they blow closer to the eastern edge of the sector or to southerly, the weather changes very sharply. The eastern winds are associated with the movement of the cyclone and carry heat, and the southeastern winds - with the outflow of cold inland air and carry cold. Influence of terrain on the climate of Antarctica
On the climate of Antarctica affects and terrain influence... Here, in the same area, a severe storm with a blizzard and calm weather can be observed at the same time, although there are no big differences in the relief at all. This is how the expedition members describe the trip to Mirny.In early August, we had to go to the inspection at one of the remote stations, 4 km from Mirny, and, like Mirny, which was located not far from the coast. The weather was clear, a weak southeast wind (5 m / sec) was blowing. Having left for the transmitting radio station, we saw ahead of us, as it were, a veil of fog, which thickened and rose as we approached the sea. A few minutes later, the all-terrain vehicle drove into a strip of snow. Thousands of small streams moved along the ice surface, merging into separate streams. The further we moved, the more dense the streams became, as if nestling one against the other, until they merged into a huge milky white river. And now we are crossing the "river" ford. The level of the blizzard is getting higher, soon it closes the tracks of the all-terrain vehicle, and then the windshield. You have to go blind. In order not to go astray, we climb onto the cockpit. The station is not visible, only the State flag fluttering on the mast is visible. When we approached the station and got out of the car, it was impossible to walk, our feet slipped on the ice polished by blizzards, and the wind instantly knocked us down. A storm was raging here. The wind speed was three times stronger than in Mirny. And at the station, located on the fast ice, at that time it was completely quiet. People who were not on duty went skiing. Chicks have begun to hatch in the neighboring emperor penguin colony.The influence of the terrain especially affects the temperature regime.... Striking, for example, are the unusually low temperatures at Pionerskaya station (69 ° 44 "S), located at an altitude of about 3 km. The average annual air temperature at this station is below 38 °. It is interesting that at approximately the same latitude, but in the northern hemisphere of Kola station (near Murmansk, 68 ° 53 "N,), the average annual air temperature is -5 °. At Pionerskaya station, the highest temperature was -13 °, and at Kola station + 32 °. There are many such examples.
The climate of Antarctica depends on the thinness of the air
Severity climate of Antarctica, especially in inland areas, is also exacerbated by rarefaction of air caused by significant heights above sea level.
The severity of the climate of Antarctica. At the Pionerskaya station, for example, the air pressure is one and a half times lower than at Mirny. With this pressure, any quick movement disrupts the breathing rhythm, a person quickly gets tired even from a small physical activity. Stripping before going to bed, sitting on a bunk, and then climbing into a sleeping bag caused the same heartbeat as after a long and fast run. It is especially difficult in such conditions to perform hard physical work. There was such a case on the expedition. Immediately after arriving at Pionerskaya, it was necessary to dig a room in the dense snow for the production of hydrogen, necessary for the release of pilot balloons and radiosondes. It was possible to dig a room with a bulldozer, but how to make a roof? There was nothing at hand, except for a few fragile rods and two or three drill pipes. Putting them as a ceiling, they began to cover the room with a tarpaulin. The roof was flimsy, but it held on. We started to equip the gas generator. Finished work at 2 o'clock in the morning (it was a round-the-clock spring day). After a little rest, we decided to start producing hydrogen. Imagine the chagrin when, having come to the gas generator, they saw that on the roof a blizzard had blown a huge sastrug. The slabs caved in. It was dangerous to climb into the room. Soon, all this mass of snow collapsed, filling up all the equipment. The snow had to be thrown out manually, as the bulldozer could break the devices. Here the low pressure also affected. Throwing each shovel of snow to a height of 2-2.5 m caused shortness of breath. After making several throws, people fell off their feet. And then there was a continuous blizzard, nullifying the results of all works. To make reliable floors, it was necessary to disassemble the flooring of the only tractor sleds at the station. But the sleigh was far away. The tractor was not working. The boards had to be ripped from the sled and dragged around. We walked slowly, carrying two boards. Here, throwing the boards aside, the radio operator Ushakov fell into the snow. He was carrying three boards and his breath caught in his throat. Throwing off the boards, each of us, even Zotov, who squeezed more than 90 kg on a dynamometer with one hand, stopped exhausted or lay down in the snow under a thorny blizzard. But what a joy it was when, a few days later, for the first time in the history of science, a radiosonde rose deep in Antarctica. A regular study of the high layers of the atmosphere inside the ice kingdom began in order to study more thoroughly the climate of Antarctica.These turned out to be the main regularities of the formation of the Antarctic climate, these are the main reasons for its severity. But the influence of the atmosphere on the climate of Antarctica was not the only mystery, and was not limited to climate issues. Before the eyes of the researchers, such phenomena arose that even the eminent scientists of the world could not answer. Many of these phenomena have never even been observed before. For instance: “Disappearance of the stratosphere”, snow tornadoes (blood clots); colored halos and false suns, a winter rainbow curved in the opposite direction; haze over the snow, snow haze (fog); ice cloud near the ground; colored drift, snowy fountains-geysers, summer clouds in the depths of Antarctica, whitening effect, sparks flying from hands, a neon lamp that lights up from the touch of a finger, and much more. Each of these phenomena is observed at a certain time of the year, therefore, in order to unravel them, one must at least mentally imagine these conditions.
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