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Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970's by a research group from the British Antarctic Survey (BAS) who were monitoring the atmosphere above Antarctica from a research station .The Halley Research Station BAS research stations in the Antarctic
Rumor has it that when the first measurements were taken in 1985, the drop in ozone levels in the stratosphere were so dramatic that at first the scientists thought their instruments were defective. Replacement instruments were built and flown out. It wasn't until they confirmed the earlier measurements, several months later, that the ozone depletion observed was accepted as genuine.
Evidence that human activities affect the ozone layer has been building up over the last 20 years, ever since scientists first suggested that the release of chlorofluorocarbons (CFCs) into the atmosphere could reduce the amount of ozone over our heads.
The breakdown products (chlorine compounds) of these gases were detected in the stratosphere. When the ozone hole was detected, it was soon linked to this increase in these chlorine compounds. The loss of ozone was not limited to the Antarctic. Around the same time the first firm evidence was produced that there had been an ozone decrease over the heavily populated northern mid-latitudes (30-60N). However, unlike the sudden and near total loss of ozone over Antarctica at certain altitudes, the loss of ozone in mid-latitudes is much less and much slower. Only a few percentage per year.
What Is Ozone And How Is It Formed?
Ozone (O3 : 3 oxygen atoms) occurs naturally in the atmosphere. The earth's atmosphere is composed of several layers. We live in the "Troposphere" where most of the weather occurs; such as rain, snow and clouds. Above the troposphere is the "Stratosphere"; an important region in which effects such as the Ozone Hole and Global Warming originate. Supersonic jet airliners such as Concorde fly in the lower stratosphere whereas subsonic commercial airliners are usually in the troposphere. The narrow region between these two parts of the atmosphere is called the "Tropopause".
Ozone forms a layer in the stratosphere, thinnest in the tropics (around the equator) and denser towards the poles. The amount of ozone above a point on the earth's surface is measured in Dobson units (DU) - typically ~260 DU near the tropics and higher elsewhere, Though there are large seasonal fluctuations, It is created when ultraviolet radiation (sunl
Terminology mentioned in this term paper
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BAS, British Antarctic Survey, DU,
Locations talked about in this research material
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Halley Research Station,
Keywords talked about in this research paper
ozone, ozone hole, stratosphere, ozone layer, the stratosphere, research stations, chlorine compounds, ozone depletion, global warming, Antarctica, atomic oxygen, nitrogen oxides, troposphere, British Antarctic Survey, Halley Research Station, total loss, chlorofluorocarbons, greenhouse effect, air conditioners, health hazard, ground level, skin cancer, general public, industrial product, chemicals, airliners, tropics, measurements, molecules, radiation, mid latitudes, instruments, CFCs, altitudes, Supersonic, ultra violet, by product, ironic, fluctuations, instability, smog, bromine, Concorde, stratospheric, aerosols, halogen, gases, solvents, ultraviolet, harmful,