颶風(fēng)移動速度越來越慢，這意味著更多的破壞

颶風(fēng)移動速度越來越慢，這意味著更多的破壞

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

颶風(fēng)在陸地和水面上的移動速度越來越慢，這對其路徑上的社區(qū)來說是個壞消息。

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.

根據(jù)周三發(fā)表在《自然》雜志上的一項研究，在過去的70年里，全球的熱帶氣旋已經(jīng)減緩了10%，在世界某些地區(qū)，這種變化甚至更為顯著。

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

這意味著風(fēng)暴會持續(xù)更多的時間，用風(fēng)襲擊建筑物，并帶來更多的降雨。

"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.

研究報告的作者、國家海洋和大氣管理局的熱帶氣旋專家詹姆斯·科辛說：“陸地上的減速是真正會影響人們的因素。”他指出，颶風(fēng)哈維對休斯頓的影響是一個例子，說明較慢的風(fēng)暴對城市意味著什么。

"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，去年的颶風(fēng)哈維是一個真正的異常值，”他解釋道降雨量很大，幾乎完全是因為它移動得太慢了。”

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月登陸后，“哈維”給德克薩斯州東南部帶來了一周多的降雨。休斯頓地區(qū)部分地區(qū)的降雨量高達(dá)60英寸。暴風(fēng)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，由于全球氣候變化，像哈維這樣移動緩慢的熱帶風(fēng)暴正變得越來越常見。氣候變化導(dǎo)致兩極變暖，進(jìn)而影響大氣壓力。兩極和熱帶地區(qū)之間的氣壓差越來越小，這導(dǎo)致了這兩個地區(qū)之間的大氣流變緩。

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.

風(fēng)暴就像河流中的小船一樣，乘著這些氣流前進(jìn)。“攜帶熱帶氣旋的風(fēng)本身在變慢，因此熱帶氣旋也在變慢，”科辛解釋說。

"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.

“這篇論文非常及時，”勞倫斯伯克利國家實驗室的氣候科學(xué)家克里斯提娜·帕崔克拉說，她沒有參與這項研究。她說，研究颶風(fēng)的人們傳統(tǒng)上關(guān)注的是風(fēng)暴頻率和風(fēng)速，但是降雨是這個謎題中越來越重要的一塊。

"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."

她說:“這對區(qū)域降雨總量非常重要。”“意思是，如果熱帶氣旋移動得更慢，它們可能會留下更多的降雨。”

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.

美國國家大氣研究中心的科學(xué)家上月發(fā)表的另一項研究，分析了最近的22場颶風(fēng)，得出了類似的結(jié)果，預(yù)測未來的風(fēng)暴將旋轉(zhuǎn)得更快，側(cè)翼移動得更慢，并帶來更多降雨。

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.

一場風(fēng)暴即使減緩10%，也會帶來兩倍于以往風(fēng)暴可能帶來的降雨，因為更溫暖的空氣和更溫暖的水意味著風(fēng)暴攜帶了比過去更多的水蒸氣。

And Kossin says slower storms are dangerous for other reasons.

科辛說，風(fēng)暴變慢的危險還有其他原因。