Ozone Hole Causes Mixed Antarctic Message

Recent conflicting reports about whether Antarctica is warming or cooling can now at last be explained – it is all the fault of the ozone hole.

Changing wind patterns triggered by the ozone hole are causing some areas to warm while others cool, says a new study by David Thompson of Colorado State University in America.

The temperature changes are so great that they are swamping the gradual warming trend caused by the greenhouse effect. Thompson says that the ozone hole has become “the largest and most significant” cause of climate change on the ice continent.

The climate around Antarctica is dominated by strong westerly winds that swirl around a giant vortex of cold air that forms over the continent for much of the year. This polar vortex stretches from the ground into the stratosphere.

In the past 20 years, pollution has destroyed much of the ozone layer over Antarctica. That in turn has cooled the stratosphere by as much as 10℃. The cooling does not extent to ground level, but it has had the effect of strengthening the polar vortex and the westerly winds. This in turn, says Thompson, has caused the big changes in weather patterns at ground level that have alarmed climate scientists.

British scientists working in the Antarctic peninsular have reported that region warming by 2 or 3℃ in recent decades – several times faster than the average global warming trend. Meanwhile other parts of the continent, such as the Ross Sea region in the east, have become cooler.

Category: Environment
Source: Adapted from New Scientist, 3/5/2002                       
Word count: 259 words

臭氧洞对南极产生各种影响

    最近有关南极洲是在变暖还是在变冷的各种相互矛盾的报导，现在终于可以得到解释了—这全是臭氧洞惹的祸。
    美国科罗拉多州立大学(Colorado State University)戴维•汤普森(David Thompson)的一项新研究指出，臭氧洞引起的风型的变化正在使一些地区变暖，而使另一些地区变冷。
    这些温度的变化是如此之大，以至于由温室效应引起的逐渐变暖趋势都被其掩盖了。汤普森指出臭氧洞已经成为冰雪大陆天气变化“最大、最重要”的原因了。
    南极洲的天气被强烈的西风所主宰。这股西风围绕着一巨大的冷空气旋涡打旋。在一年中的很长时间，南极大陆上方都会产生这种暖空气旋涡。这一极地旋涡从地面一直延展到大气平流层。
在过去20年中，污染已经破坏了南极洲上空面积的臭氧层。这种破坏的结果使得大气平流层的温度下降了多达10摄氏度。这种降温并没有延伸到地面层，但是它有加强极地旋涡和西风的效果。汤普森说，这种效果转而引起了地面层天气型态的重大变化，这一点已经引起了气象学家的警觉。
在南极半岛工作的英国科学家们已经报告，该地区温度在近几十年来已经上升了2至3摄氏度。这样的变暖速度比全球平均变暖趋势要快好几倍。而与此同时，南极大陆其它一些地区，如东部的罗斯海(the Rose Sea)，则已经变得更冷。