Dawn of a new ozone hole
provided by NASA | |
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Each year around this time, the ozone hole begins to open as light from the springtime Sun triggers the chemistry of ozone destruction. It's an annual event. The hole widens in mid-August, then contracts again in December - a cycle shaped by south polar weather. Last year's ozone hole was a record-setter: it grew to be three times larger in area than the entire land mass of the United States. The hole was so far-reaching it exposed towns in southern Chile and Argentina to elevated levels of ultraviolet sunlight. This year's hole has been opening since mid-August, and it appears to be another big one. “Right now it's too early in the season to say anything definitive about how [the 2001] hole will come out. But we can say that it will be a big ozone hole, like it has been the last few years,” says Paul Newman, an atmospheric physicist at NASA's Goddard Space Flight Center. “It will certainly exceed 25 million square kilometers in size,” he says. In comparison, the North American continent is about 21.5 million square kilometers. |
For current pictures and info, see: science.nasa.gov/headlines/y2001/ast17sep_1.htm?list15423 | |
n a few days, spring is replacing winter across our planet's southern hemisphere. At the South Pole itself the Sun will peek above the horizon for the first time in months. And while the returning Sun will surely be a welcome sight in that frozen land, with it comes a less popular springtime event: the return of the ozone hole.