拉尼娜现象

And so they tend to get strong and last long during a la Nina situation.

拉尼娜现象使飓风容易增强并持续长久。

It is followed by a cooling period, known as La Nina.

在其过后迎来了一个降温过程，就是我们所知的拉尼娜现象。

La Ninas and El Ninos happen about every three to five years.

大概每隔三至五年就会发生拉尼娜现象和厄尔尼诺现象。

This year´s la Nina started building late last summer and was mature by January, Arndt said.

阿尔·恩特说，今年的拉尼娜现象从去年夏末开始形成，在一月成熟。

Please read the following article and find out what role El Ni?o and La Ni?a play.

请阅读以下文章，看一看厄尔尼诺和拉尼娜现象所起的作用。