什么是“炸弹旋风”？

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When it comes to weather, it is hard to sound more frightening than to call a storm a "bomb cyclone."
谈到天气，很难听到什么比“炸弹旋风”更可怕的了。

But that is how weather experts are describing a huge winter storm that is hitting the U.S. East Coast this week.
但是气象专家正以此形容本周正在冲击美国东海岸的一场冬季大风暴。

From the northern state of Maine to Georgia in the south, the storm has brought high winds and heavy snow. Schools and government offices have closed because of the weather and thousands of flights have been cancelled.
从北部的缅因州到南部的乔治亚州，这场风暴带来了狂风和暴雪。学校和政府部门因为天气原因关门，还有数千趟航班被取消。

But as fearsome as the storm is, it probably will not be as "explosive" as the name sounds.
但是虽然风暴很可怕，它可能却没有这个名字听上去那么“具有爆炸性”。

Weather experts, or meteorologists, have used the term "bomb" for storms for many years. The word has a clear definition for weather experts, says University of Oklahoma meteorology professor Jason Furtado.
气象学家多年来一直把“炸弹旋风”这个术语用于表示风暴。俄克拉荷马大学气象学教授Jason Furtado表示，对气象学家来说，这个词有着明确定义。

After "bomb cyclone" appeared in a Washington Post story this week, the weather term became popular, or "blew up," on social media. It became a top trending topic. The same thing happened four years ago with the phrase "polar vortex" -- another long-used weather term that was not well known to the public.
在本周《华盛顿邮报》的一则新闻中出现“炸弹旋风”之后，这个气象术语在社交媒体上流行开来，成为了一个热门话题。同样的情况发生在4年前，当时是“基地漩涡”这个词语，这是另一个不为公众熟知的长期使用的气象术语。

The technical term is "Bombogenesis." Bomb cyclone is a shorter way of saying it, which is better for social media, says meteorologist Ryan Maue. He helped popularize "polar vortex" in 2014.
气象学家Ryan Maue表示，专业术语是“Bombogenesis”，炸弹旋风是它的简称，当然这个简称更适合社交媒体。他在2014年帮助“基地漩涡”这个术语得到了普及。

Although "bomb cyclone" sounds bad, Maue notes, nothing will actually explode.
虽然“炸弹旋风”听上去不是什么好事，但是Maue指出，没有什么会真的爆炸。

Storm strength is measured by central pressure. The lower the pressure, the stronger it is. A storm is considered a "bomb" when the pressure drops quickly -- at least 24 mililbars in 24 hours.
暴风强度是通过中心气压来衡量的。中心压力越低，风暴越强。当一场风暴的中心气压迅速下降 -- 在24小时内至少下降24毫巴（百帕），它就被认为是“炸弹旋风”。

This week's storm in the United States is expected to strengthen at two times that rate, says Bob Oravec. He is the lead forecaster at the National Weather Service's Weather Prediction Center.
Bob Oravec表示，美国本周的风暴预计以该速度的两倍增强。Oravec是美国国家气象局天气预报中心的首席预报员。

Around the world, about 40 to 50 bomb cyclones develop each year. However, most are over the open ocean and few people notice them.
全球每年大约会爆发四五十个“炸弹旋风”。然而，其中大多数位于公海之上，很少有人会注意到它们。

"We use the term bomb," Furtado said. "We (weather experts) know what it means, but I do think it gets a little hyped up."
Furtado表示：“我们使用‘炸弹旋风’这个术语，我们气象专家懂它的意思，但我确实认为它有点夸张。”