World Weather, Climate, and Society Projects |
Mawson Station, Antarctica Alex Broughman, Kara Evanko, Emily Greene History The Antarctic Circle was first breached by James Cook, of Great Britain, in 1773. He was forced north of Antarctica twice due to ice, which lead him to underestimate the value of the continent. As a result, many governments stopped funding Antarctic expeditions. He did, however, note the number of whales and seals that inhabited the waters. Hunters flocked to the Antarctic Circle, where they killed millions of seals, driving them to near extinction on many of the islands. It was actually these hunters who would map the Antarctic coast as they searched for new hunting grounds. It was bad weather, including strong winds that pushed hunters further south, into new hunting grounds, resulting in more charted islands. In 1820, the British government sent an expedition, which landed on Livingston Island. Not only were they first group to actually see the continent, they also were the first to take scientific specimen from the region. Not until 1821, did anyone land on Antarctica. In 1895, the Sixth International Geographic Congress, called for scientists from numerous countries for further Antarctic exploration. In 1899, the first group managed to winter-over on the inhospitable continent. Throughout the first two decades of the twentieth century, there were many Antarctic expeditions, including one that finally reached the South Pole. Some encountered disastrous situations; their boats getting caught in the ice, or explorers falling into crevasses. At the same time, new whaling technologies prompted an influx of whalers. In 1935, one of these whalers brought his wife, who was the first woman to land on Antarctica. During the World Wars and inter-war period, whalers were the predominant explorers in the Antarctic, as governments were busy elsewhere. Byrd via his continental flights in the 1920’s was the first person to prove that Antarctica was a single landmass. The 1930’s brought a surge in government claims to Antarctic land. Major scientific interest revived following World War II. The first birth was given on the continent in 1978, because Argentina sent the mother to give birth on Antarctica. There are also sight-seeing tours over the continent. The British, Australian, New Zealand, Russians, Argentineans and Americans established stations in the Antarctic1. History of Mawson Station In 1929 and 1931, Mawson was a member of the British, Australian and New Zealand Antarctic Research Expeditions (BANZARE). These expeditions were huge successes both scientifically and territorially, as Mawson claimed 42% of Antarctic for the British (transferred in 1935 to the Australians). At the same time that Mawson and BANZARE were mapping the inland of Mac Robertson Land, Norwegian whalers were charting the coast and naming other facets of the region including the Framnes Mountains. Mawson became a proponent of permanent Australian presence on the continent and in 1947, this was accomplished with the Australian National Antarctic Research Expeditions (ANARE) being dispatched to the Heard and Macquarie Islands. In 1953, American aerial photographs we re Nowadays, Mawson plays host to numerous scientific programs. These include biology programs studying the diets and breeding patterns of Weddell seals, Emperor penguins, and Adelie penguins. There is also a geomagnetic observatory which records seismic events. Perhaps one of the most important studies is one which records the winds and temperatures 95-250km above the station. This allows for comparisons, which help to research the global climate change. Water that is released from the Antarctic ice-sheet in the summer collects in caverns and then the waste heat is used by the station’s power generators. Life at Mawson is comfortable; there are individual living quarters, three meals a day served in the mess hall, and the huts are maintained at 18 C. Ho we ver, sho we rs are limited to three minutes each. Supply ships usually come two or three times a year. The staff ho we ver, arrives by helicopter2. 1 “Antarctic History.” http://www.antarcticaonline.com/antarctica/history/history.htm Climate There are three climatic regions in Antarctica. The interior of the continent is extremely cold with little snowfall. Antarctica ’s climate is characterized by low temperatures, high wind velocities, and frequent blizzards. The interior of Antarctica is the coldest place on earth due to its high altitude and continual darkness in winter. Although the coldest temperature ever recorded anywhere on earth, -128.6 degrees F, was recorded here, temperatures usually range from approximately 0 to -70 degrees F. The continent is buffeted by strong winds; calm periods are rare and typically last only a few hours. The winds flow downwards from the interior toward the coast and are driven largely by gravity as air cools and becomes denser over the pole. These winds are known as “katabatic winds” and when they reach the coast, they produce a west-flowing ocean current known as the East Wind Drift, which is caused by the rotation of the Earth. Turbulent winds of high velocities, frequent snowstorms, and volatile coastal weather are three of the most notable features of the Antarctic climate. The most powerful cooling factor of Antarctica ’s climate is its wind chill. It is the major obstacle researchers and explorers face in attempting Antarctic expeditions. Fierce winds are common in most coastal regions, especially East Antarctica, where cold and denser air flows down the steep slopes off the interior highlands. Turbulent winds here can reach up to 155 miles per hour. Winds on the polar plateau are usually light, with velocities usually ranging from 9 to 17 milers per hour. (See download link for climate data above.) Due to its low temperature, Antarctica lacks a substantial water-vapor atmospheric layer that would absorb and radiate solar waves. This causes Antarctica ’s surface to lose a tremendous amount of heat energy to space. Antarctica ’s outgoing solar radiation greatly exceeds its incoming. This loss results in intense surface cooling, and gives rise to the temperature inversions common to Antarctica. Temperature increases from the surface upward to about 1,000 feet. About 90 percent of the radiation loss is replaced by atmospheric heat from lower latitudes, and the remainder by latent heat of water-vapor condensation. The atmospheric water-vapor comes from ice-free regions of the southern oceans and is transported through the troposphere into Antarctica. Most of this water precipitates as snow along the continental margin; Rainfall is practically unheard of. Despite the huge volume of water stored as ice, Antarctica is considered one of the world’s greatest deserts. The average precipitation is only about two inches in the interior and ten inches in the exterior. As easy as it is to forget about such a cold and uninhabitable place, researchers are using Antarctica to help uncover the climatic history of our planet and to understand more about current environmental problems. Low-frequency radio waves (whistlers) in Antarctica ’s upper atmosphere, caused by lightening at opposite points in the Northern Hemisphere, are received by Antarctica, and provide valuable information about the magnetosphere. This and other research on the continent has vastly contributed to scientific understanding of the ionosphere, geomagnetism, and solar cosmic radiation. Antarctic ice glaciers are possibly providing documentation of the global warming, which is currently a major environmental concern. Current research in Antarctica has focused on the “ozone hole” centered over East Antarctica, in which a loss of stratospheric ozone is occurring every spring and is increasing exposure to damaging ultraviolet light. The ozone hole is caused by the effects of pollutants, such as nitrogen oxides and halogens, in the atmosphere that are destroying stratospheric ozone. During the Antarctic winter, strong winds blowing around the continent create a “polar vortex” that isolates the air over Antarctica from the rest of the world. This polar vortex then forms special clouds, called “Polar Stratospheric Clouds,” that have the effect of concentrating the pollutants that break down the ozone. Ozone depletion occurs mainly during the first few weeks after the end of the Antarctic winter darkness because a lot of these ozone-depleting chemical reactions need sunlight. When spring arrives, the ozone levels begin to severely deplete around the Antarctic continent causing this “ozone hole,” and unfortunately, the high sunshine and long days make this effect even worse. These pictures show the extent of the ozone thinning. Dark blue colors correspond to the thinnest ozone, while light blue, green, and yellow indicate progressively thicker ozone.
Weather Summer Winter Another factor that keeps Antarctica very cold in the winter is the lack of moisture. As the world’s largest desert, Antarctica has an annual rainfall of less than 2” and an average humidity of less than.03%. That means that very little heat that is radiated or reflected from the surface is not absorbed by moisture in the air. In addition, Antarctica grows to about twice its size during the winter as the surrounding seawater freezes. Because of this, heat transfer from the relatively warm surrounding ocean is reduced significantly. Because of Mawson’s location on the coast, this phenomenon has much less impact there than it does on the huge inland plateau. Most of Antarctica undergoes what is known as a “coreless winter,” in which surface temperatures remain relatively the same from the beginning of winter to the end. Evident in the chart, average temperatures at Mawson stay within a roughly five degree range from April to September. This is due primarily to the fact that most heat at this time comes not from sunlight, but from surface radiation, which establishes equilibrium and remains roughly constant throughout the winter. This does not occur in the Arctic, where surface characteristics change much more with the seasons. Note that in the South Pole chart, the coreless winter is much more exaggerated. This is caused by the much smaller absorbency of solar radiation there as opposed to the rocky area of Mawson, which is able to absorb much more energy than ice or snow. Still, however, Mawson does experience a less extreme version of a coreless winter. Fall and Spring Recently Conclusion
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Antarctica was discovered in 1773 and lacks an indigenous human population. Researchers and explorers from numerous countries have a constant presence, while battling the coldest, windiest and most treacherous climate on Earth. Recently, Mawson Station has been beset by blizzards and slow, springtime warming. Currently, two of the most prominent environmental concerns, global warming and ozone depletion, involve Antarctica. In examining Antarctica ’s history, climate, and weather, we have discovered a continent often dismissed as desolate and boring to be one of the most fascinating places on Earth. 
At this time the seal population was desecrated, and some hunters in search of new hunting grounds stumbled onto the frozen continent. Even though there was a lull in seal hunting, many of these sealers remained active as they became scientists; these people can be accredited with taking the first Antarctic fossils, charting lands, and in Wendall’s case estimating the minimum seal population that would have been needed for population management that would have permitted further hunting. As more the interest in the continent turned scientific, the race to find the magnetic South Pole intensified. And with this race came new charted territory and in the 1850’s new discoveries of seals. 
Recently, emphasis has been placed on examining the ice layers. Climatic history can be examined dating back to half a million years ago. At that time, the world was dustier and windier and it snowed more frequently. Researching the past climates, scientists can discover if there have been major climatic changes, shedding light onto the global warming debate. CO2 trapped in ice allows scientists to determine past climates and thus compare it to the present climate in order to examine the issue of global warming.
Mawson station is the oldest establishment within the Antarctic Circle. Mawson, Antarctica was bequeathed its name for one of Australia ’s greatest scientific, Antarctic, explorers. Douglas Mawson moved to Australia from Great Britain when he was just two. He taught geology and studied glacial activity. In 1907, he participated as chief physicist on one of Ernst Shackleton’s expeditions. In the following years he climbed Mt. Erebus and was the first to cross the magnetic South Pole. In 1911, Mawson organized his own expedition which can be credited for the first wireless signals from Antarctica to the world. He established two stations, one on the Commonwealth Bay and the other on the Shackleton Ice Shelf.
used to decide the ideal location for an over-wintering station. In 1954, they established their first station on the continent in Mac Robertson Land- it was fittingly named Mawson. This first group erected living quarters, works hut, the engine shed, two store huts and a carpenter’s shop- these facilities expanded to over 50 in 1966. In 1956, Mawson became home to the first aircraft hangar and later Antarctica ’s premier cosmic ray observatory was built out of the rocks of Mawson’s foundation.
The coastal areas have milder temperatures (comparatively speaking) and much higher precipitation rates (though still in the desert range). The Antarctic Peninsula region has a warmer and wetter climate and above-freezing temperatures are common. There are many factors that determine Antarctica ’s climate, but the most significant one is the geometry of the relationship between the Earth and the Sun. The 23.5 degree axial tilt of the Earth to its annual plane of orbit around the Sun results in long winter nights and long summer days. The amount of solar radiation (heat) that Antarctica receives depends on the incident angle of the Sun’s rays. This angle decreases inversely with latitude to reach a minimum at the geographic poles. The high elevation and reflective snow intensify its polar climate. Antarctica is a continent surrounded by ocean and during Antarctic winters, the freezing of the surrounding sea moves the oceanic heat source to nearly 1,800 miles from the central polar plateau. 
The harsh climate also causes a few exciting visual effects; the dust-free air makes it possible to see for tens of miles, and since distances are often deceptive, mirages are very common. This picture shows an ice mirage. Also, blowing snow or low clouds cause a scattering of light that can result in whiteout conditions, in which the horizon is eliminated by the sky, visually blending it with the snow-covered surface of the land. 
On the other hand, the clear atmosphere is a poor absorber and emitter of infrared energy. Thus, clear winter days in Antarctica are generally the coldest because the surface is emitting more energy than it is absorbing, and cloudy days are the warmest because clouds can emit more energy toward the surface than the surface is emitting toward space. Because of Antarctica ’s reliance on infrared energy for heat, it is the site of a phenomenon called “temperature inversion,” in which the surface temperature is often significantly cooler than the temperature of the air high above the surface. This is different from most other parts of the world, where the temperature of the lower atmosphere steadily decreases with altitude. This phenomenon occurs because the surface is giving off infrared energy and cooling, and it cools the air closest to it more efficiently than the air higher up, and in Antarctica this is unmitigated by any significant warming by sunlight. 
We’ll never again think of Antarctica as a boring ice cap, home only to penguins. The continent has a rich history of exploration and is currently making history furthering scientific understanding. Although we never plan to personally visit, this project has expanded our global knowledge to include an important and unique territory that is often overlooked.