题型:阅读理解 题类:常考题 难易度:普通
外研版(2019)高中英语必修1 Unit 4 Friends Forever单元测试
Tropical cyclones (热带气旋), including hurricanes and typhoons, are now moving at a slower speed than they did decades ago, new research shows.
While having a cyclone travel with less speed may seem like a good thing, it's actually just the opposite. Wind speeds within the storm remain high, but the whole system itself moves slower, allowing punishing rains to stay longer over communities. "Nothing, good comes out of a slowing storm," says James Kossin, author of the paper. "It can increase the amount of time that buildings suffered from strong wind. And it increases rainfall."
In his paper, Kossin showed that from 1949 to 2016, tropical cyclones across the globe slowed their movement by 10 percent on average. In some regions (地区), the speed of those storms slowed even more as they hit land. In the western North Pacific, the decrease was much more manifest ― almost a third. That means a storm that may already hold more moisture (水分) will have time to drop more of it in each spot.
Kossin's work was based on details of almost 70 years' worth of storms, but he didn't try to determine what was causing the slowdown. Still, the change is exactly what he and other cyclone experts said, which would be expected from climate change. With the polar regions warming fester than other parts of the globe, that is changing the pressure and reducing the winds that push these storms.
Christina Patricola, a scientist, called Kossin9s work important and new and said she found it reliable. "I was not surprised by his findings," she says. "But I was surprised by the speed of the slowdown."
Kossin hopes that scientists will begin building models that show which places are likely to face the most risk. Given that storms in some regions are moving towards polar regions and already increasing in intensity (强度), cyclones causing unusually powerful rain may threaten places not normally in their paths. Scientists must take action to make those places suffer less from the disasters.
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