美国有线新闻 CNN 飓风"艾达"登陆美国路易斯安那州（在线收听）

Yesterday, a major hurricane made landfall in the U.S. state of Louisiana.

昨天，一场大飓风在美国路易斯安那州登陆。

Landfall is when a hurricane's eye, it's center, is halfway over a coast and the eye of Hurricane Ida arrived in Port Fourchon Sunday afternoon.

登陆指飓风眼也就是飓风中心的一半已移动到海岸上，飓风“艾达”的飓风眼于周日下午抵达富尔雄港。

When it hit, the storm's sustained wind speeds were 150 miles per hour, that made Ida an extremely dangerous Category 4 hurricane.

“艾达”来袭时，持续风速为每小时150英里，这使“艾达”成为极其危险的4级飓风。

As it approached, Louisiana Governor John Bel Edwards said the storm could be a big challenge for his state,

路易斯安那州州长约翰·贝尔·爱德华兹在“艾近”临近时表示，这场风暴对他的州来说可能是一个巨大挑战，

and a New Orleans Homeland Security Official told people to stock up on enough food and water for at least three days.

新奥尔良国土安全局的一名官员告诉人们，要储备足够至少三天使用的食物和水。

Some Louisianans were ordered to leave their homes. Schools were closed in that state and parts of neighboring Mississippi.

部分路易斯安那州居民被勒令离开家园。该州和邻近的密西西比州部分地区的学校已经关闭。

Hundreds of thousands lost power.

数十万人断电。

Airlines cancelled all flights at Louis Armstrong-New Orleans International Airport, and a lot of officials were concerned about the city of New Orleans.

航空公司取消了路易·阿姆斯特朗新奥尔良国际机场的所有航班，许多官员对新奥尔良市感到担忧。

It's 50 miles north of where Hurricane Ida made landfall, and that occurred 16 years to the day after Hurricane Katrina hit this region.

新奥尔良市 位于飓风“艾达”登陆地以北50英里处，16年前曾遭飓风“卡特里娜”袭击。

It caused catastrophic failure in the levees that protected the city from flooding, contributing to the deaths of 1,500 people.

“卡特里娜”导致保护城市免受洪水侵袭的防洪堤遭遇灾难性破坏，造成1500人死亡。

A city official said New Orleans was better protected than it was when Katrina hit, but that flooding there was still possible.

一名市政府官员表示，新奥尔良的保护措施比“卡特里娜”袭击时更好，但该市仍有可能发生洪水。

And as Hurricane Ida blew in, that city in addition to some other areas of Louisiana temporarily suspended their emergency response services

飓风“艾达”来袭时，该市以及路易斯安那州的一些其他地区暂停了应急响应服务，

because it was too dangerous for rescuers to go out in the hurricane.

因为救援人员在飓风中外出过于危险。

Ida wasn't even classified as a tropical storm until last Thursday, it strengthened quickly because of a process called rapid intensification.

直到上周四，“艾达”才被归类为热带风暴，由于一个被称为“快速增强”的过程，该飓风迅速加强。

Rapid intensification is just like it sounds. A storm, a tropical storm, cyclone, typhoon hurricane, that rapidly intensifies.

“快速增强”（简称RI）就像听起来一样。指风暴、热带风暴、气旋、台风的威力迅速增强。

Now the definition is 35 miles per hour or greater in 24 hours. Now take Maria, Maria went from a Category 1 to a Category 5 in 15 hours.

现在“快速增强”的定义是风暴时速在24小时内增加35英里及以上。以“玛丽亚”为例，“玛丽亚”在15小时内从一级飓风升级为五级飓风。

For true RI, or rapid intensification, you need a couple things, 86 degrees Fahrenheit water or greater and no shear,

真正的“快速增强”需要几个条件，温度在86华氏度及以上的水，没有风切变，

and so of course, the water down in the tropics is very warm but what about this shear thing.

当然，热带的水是非常温暖的，但切变呢？

We hear about it in tornadic thunderstorms.

我们在龙卷风雷雨中听过这个词。

Those storms want a lot of shear. Wind going in different directions and different speeds with height.

龙卷风雷雨需要大量的风切变。风切变指，风吹向不同的方向，风速随高度而变化。

A hurricane wants no shear. No wind direction change, no wind speed change with height.

飓风不需要风切变。风向不变，风速也不随高度变化。

It want to be the only thing out there making its own wind, not getting blown apart.

它想成为唯一一个能形成飓风的东西，而不是被吹得四分五裂。

So why is rapid intensification important, well you can go to bed one night expecting a tropical storm and have a Category 2 on your doorstep the next morning.

那为何快速增强很重要？因为，你可能今晚睡觉时以为那是热带风暴，而第二天早上来到你家门口的已经是二级风暴了。