This visualization shows the total ozone concentrations for the Earth from January 1, 2000 through December 31, 2003, as measured by theTOMS instrument on the Earth Probe satellite. Low ozone (less than 200 Dobson units) is depicted as regions of dark blue, with high ozone (greater that 330 Dobson units) depicted as yellow and red. The most visible and dynamic feature of the ozone distribution is the ozone hole that forms over Antarctica during September of each year. The amount of ozone in the stratosphere over Antarctica is reduced during this period due to unique atmospheric conditions which chemically reduce the amount of ozone in the region and prevent that ozone from mixing with the higher ozone concentrations just outside the hole. Ozone blocks harmful ultraviolet 'B' rays, and loss of statospheric ozone has been linked to skin cancer in humans and other adverse biological effects in plants and animals. This visualization explicitly shows the TOM ozone data coverage and does not interpolate data into regions of the Earth that the instrument did not observe. Since TOMS measures ozone by observing the characteristics of sunlight reflected from the Earth's surface, no measurements are available for the poles during the polar winter, i.e., around January for the North Pole and July for the South Pole. Also, there is an unobserved region between successive satellite orbits around the equator. Finally, the instrument has periods where technical issues make measurement impossible for a matter of hours or days. This visualization shows that the dynamics of the ozone layer remain visible despite these measurement issues.
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