飓风移动速度越来越慢，这意味着更多的破坏

飓风移动速度越来越慢，这意味着更多的破坏

Hurricanes are moving more slowly over both land and water, and that's bad news for communities in their path.

飓风在陆地和水面上的移动速度越来越慢，这对其路径上的社区来说是个坏消息。

In the past 70 years, tropical cyclones around the world have slowed down 10 percent, and in some regions of the world, the change has been even more significant, according to a study published Wednesday in the journal Nature.

根据周三发表在《自然》杂志上的一项研究，在过去的70年里，全球的热带气旋已经减缓了10%，在世界某些地区，这种变化甚至更为显著。

That means storms are spending more time hanging out, battering buildings with wind and dropping more rain.

这意味着风暴会持续更多的时间，用风袭击建筑物，并带来更多的降雨。

"The slowdown over land is what's really going to affect people," says James Kossin, the author of the study and a tropical cyclone specialist at the National Oceanic and Atmospheric Administration. He points to Hurricane Harvey's effect on Houston as an example of what slower storms can mean for cities.

研究报告的作者、国家海洋和大气管理局的热带气旋专家詹姆斯·科辛说：“陆地上的减速是真正会影响人们的因素。”他指出，飓风哈维对休斯顿的影响是一个例子，说明较慢的风暴对城市意味着什么。

"Hurricane Harvey last year was a real outlier in terms of the amount of rain it dropped," he explains. "And the amount of rain it dropped was due, almost entirely, to the fact that it moved so slowly."

“就降雨量而言，去年的飓风哈维是一个真正的异常值，”他解释道降雨量很大，几乎完全是因为它移动得太慢了。”

Harvey dumped rain on Southeast Texas for more than a week after it made landfall in August 2017. As much as 60 inches fell on some parts of the Houston area. At least 93 people died as a result of the storm.

在2017年8月登陆后，“哈维”给德克萨斯州东南部带来了一周多的降雨。休斯顿地区部分地区的降雨量高达60英寸。暴风雨造成至少93人死亡。

The new research suggests slow-moving tropical storms such as Harvey are becoming more common because of global climate change. Climate change is causing the poles to become warmer, which in turn affects the atmospheric pressure. There is less and less difference in pressure between the poles and the tropics, and that causes the big currents of wind between the two areas to slow down.

新的研究表明，由于全球气候变化，像哈维这样移动缓慢的热带风暴正变得越来越常见。气候变化导致两极变暖，进而影响大气压力。两极和热带地区之间的气压差越来越小，这导致了这两个地区之间的大气流变缓。

Storms ride on those currents of wind, like a boat in a stream. "The wind itself that carries the tropical cyclone within it is slowing down, and therefore the tropical cyclones are slowing down," Kossin explains.

风暴就像河流中的小船一样，乘着这些气流前进。“携带热带气旋的风本身在变慢，因此热带气旋也在变慢，”科辛解释说。

"This paper is very timely," says Christina Patricola, a climate scientist at Lawrence Berkeley National Laboratory who was not involved in the research. She says people who study hurricanes have traditionally focused on storm frequency and wind speed — but that rainfall is an increasingly important piece of the puzzle.

“这篇论文非常及时，”劳伦斯伯克利国家实验室的气候科学家克里斯提娜·帕崔克拉说，她没有参与这项研究。她说，研究飓风的人们传统上关注的是风暴频率和风速，但是降雨是这个谜题中越来越重要的一块。

"This is really important for regional totals for rainfall," she says. "The implication here is that if tropical cyclones are moving more slowly they have the potential to leave more rainfall."

她说:“这对区域降雨总量非常重要。”“意思是，如果热带气旋移动得更慢，它们可能会留下更多的降雨。”

Another study, published last month by scientists at the National Center for Atmospheric Research, analyzed 22 recent hurricanes and found similar results, predicting that the storms of the future will spin more quickly, move sideways more slowly and bring more rain.

美国国家大气研究中心的科学家上月发表的另一项研究，分析了最近的22场飓风，得出了类似的结果，预测未来的风暴将旋转得更快，侧翼移动得更慢，并带来更多降雨。

A storm slowing down even 10 percent can lead to twice as much rain as previous storms might have brought to a particular area, because warmer air and warmer water mean storms are carrying more water vapor than they used to.

一场风暴即使减缓10%，也会带来两倍于以往风暴可能带来的降雨，因为更温暖的空气和更温暖的水意味着风暴携带了比过去更多的水蒸气。

And Kossin says slower storms are dangerous for other reasons.

科辛说，风暴变慢的危险还有其他原因。